Category: Tea

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Coffee review Coffee Roasters Observations Science history slow Tea

HR Higgins, Duke Street

Interior of HR Higgins cafe
The view of H.R. Higgins (Coffee-man) from Duke Street. The Royal Warrant can be seen on the side of the wall.

Established over 80 years ago, HR Higgins in Mayfair’s Duke Street is somewhat of an institution. From the pavement, you can look into the cafe space in the basement below while the shop upstairs offers coffee beans and tea for retail. During the (earlier) mornings, coffee is also prepared for take-away at the entrance to the shop on the ground floor while the cafe downstairs is closed.

The first time I came here, it was only to buy beans. That time I tried the Rwandan Women’s cooperative coffee and was impressed by the scales used to weigh out my 250g: a proper mechanical scale set complete with weights. The second time I tried it, again I only had time to purchase beans but I determined that the next time I would definitely try the cafe downstairs because if there was so much physics to appreciate upstairs with the scales and the decor, how much more would there be downstairs. And so, I arrived one morning at 8.30am having checked the opening hours and the cafe downstairs was… closed. It turns out that although the shop is open, and although take-away coffee is served from the front of the shop, the cafe only opens much later at 10am (on weekdays).

Inside an empty cafe.
Inside an empty cafe, downstairs at Higgins. The clock on the wall is a throw back to the ’70s while the mosaic tiling on the floor is particularly mesmerising. What strikes you?

However, what was an initial disappointment turned into a great opportunity as I was able to have a proper look around, completely on my own, while the man upstairs prepared my V60. Having no intention of actually ‘taking-away’ the take-away, when I came back upstairs (and had another look at the scales and tins of coffee at the back of the store) I went outside to the “H.R.Higgins” bench to sit and enjoy my coffee and the surroundings. There were a few pastries that were also available for take-away but this time I just took my coffee and sat down.

The coffee was really good. I had been given a choice of two coffees for the V60 and went for the Honduran as it was recommended as being particularly good for the V60 brew method. It was packed with flavour notes and character as it cooled while I sat on the bench. The bench offered a view of city life. The busy cafe next-door to my left; the old sign “Duke Street, W”* on the wall opposite; the imposing “Brown Hart Gardens” which is above an early 2oth century electrical substation just to my right and of course, the cafe itself in the basement visible behind me. The bench was also a good spot for people watching. Many people, with many characters, walked past (or got their coffee in Higgins and then walked past). I thought perhaps that I even saw George Osborne** wandering by but decided to let my mind wander to think about the physics instead.

Of course there was a lot to ponder. The nature of scales and the definition of the kilogram had been an obvious starting point but the reflection of the cafe name in the window opposite me provided further directions of thought. The patterns of the tiling in the cafe could provide several avenues of thinking while the history involved with the establishment of this establishment would have prompted a significant diversion. Finally, the antique bike standing next to the bench took me on the thought-journey that occupied the rest of the time I spent on the bench and enabled me to keep my phone left solely for taking photographs.

An old bike with flowers where a delivery box used to be.
The H.R. Higgins bike. Complete with Brookes saddle and flowers for luggage, this bike gave plenty to ponder while enjoying a coffee.

Now used as a flower pot holder, this old bike looked as if it had been adapted from a delivery bicycle of a fair few years ago. The brakes were immediately attention grabbing. We have become used to the wires used to operate the brakes on modern bikes but these used firm metal rods to transfer the action on the brake levers on the handle bars down to the wheels. And then the wheels themselves had rubber tyres. Again, this is somewhat obvious and very familiar except the first bikes had iron wheels because rubber tyres had to be invented.

There is a potential diversion here to the story of rubber, which could almost be a cafe-chemistry review but we won’t go that way today. Nonetheless, it is worth pondering that rubber tyres are, just like coffee, a product with a varied history of globalisation, trade and colonisation. What enabled the bicycle wheel to evolve from cast iron to pneumatic tyres was the chemistry involved in the ‘vulcanization’ process invented by Goodyear that meant that the rubber no longer suffered from getting too soft at higher temperatures and too hard at lower temperatures. Anyway, that’s a digression.

Returning to the bicycle, a lot of physics is involved in cycling. Is it actually clear how any of us can balance on a bicycle? A short answer, and the one that is often off-handedly given, is that we can cycle because of “conservation of angular momentum”, but it turns out that it is a little more tricky than just that. A few years ago, a chemist decided to test the ideas put forward to explain how we balanced on a bicycle by building so-called “un-ridable” bicycles and found that he could actually ride some of them, thereby showing that some of our ideas on bicycle riding needed a little ‘tweaking’. The basic ideas of conservation of angular momentum were correct, but like many things, if you actually want to understand it, you need to go a bit deeper (and do a couple of experiments!).

As we move beyond the basic physics so we move to the technology of cycling and the improvements that are being made to competitive cycles (and their riders) to make them more aerodynamic. We have moved a long way from brakes using rods and delivery cycles. And yet, sometimes there are advantages to the old ways. Just as the scales at H.R. Higgins still work perfectly well with the balance and weights system, so new delivery bicycles are re-appearing in London, swapping polluting vans for cleaner-greener delivery vehicles. Just these ones no longer have metal rods for brakes and they perhaps have a pedal-assist electric motor.

Have you enjoyed a coffee at H.R. Higgins (or somewhere similar)? What did you notice that enabled you to put your mobile phone down and really think about your surroundings? Do let me know in the comments section here or via social media.

H. R. Higgins is at 79 Duke Street, Mayfair, W1K 5AS

*The single “W” on the sign (rather than the post code of the area “W1”) shows that the sign has been there since before the first World War when the London post code system was refined from the merely “W” to the W1, W2 etc. that we use now.

**George Osborne was the Chancellor of the Exchequer (finance minister for the UK government) from 2010 to 2016.

Categories
Home experiments Observations slow Tea

Time for tea?

Matcha, tea in Japan, frothy tea
A Matcha tea in Japan. A lot to contemplate here.

A recent article in Caffeine magazine caught my attention. Emilie Holmes of Good and Proper Tea was writing about the joys of appreciating loose leaf tea. While tea is a little diversion from coffee, January is traditionally a time to look forward as well as back and maybe, BeanThinking should occasionally cross over to the tea side. It was one line in particular of that article that puzzled me. Writing about the ‘naturally “slow” nature of the tea ritual’, Holmes observed that while brewing loose leaf tea you would be able to see “the leaves in a glass pot emit wisps of colour as they infuse…”

It was great to read someone who clearly had spent time carefully observing their tea. And yet that sentence prompted a series of questions in my mind. It was not that I doubted the observation, indeed, thinking back to teas I have made and enjoyed, I realise that I have seen these wisps before. It was more a question of why would it happen, why would the brewing tea emit lines of colour from the leaves? These lines must be telling us something.

diffusion, convection, tea brewing
A tea bag in hot water. The lines of tea are difficult to see in the photo, you’ll just have to do your own experiments, but, streaming from the bottom of the bag, you can see wisps of darker tea-water.

We need to think about how tea brews. A first mechanism would be through turbulence. Hot water poured onto a bed of tea leaves would stir them up and the resulting movement within the pot would mix the leaves with the water leading to a properly brewed cup of tea. This is very much the lazy tea brewers bag-and-cup method (which I can share). It would lead to a brewed tea, but it could not lead to a situation in which you could sit back and see wisps of colour. That requires calm and the quiet moments of a pot of tea brewing while you can enjoy the process.

A second mechanism would be through diffusion. Ultimately the same mechanism as the principle behind how LEDs work, diffusion is where the soluble parts of the tea leaves would travel, through the process of a random walk, throughout the water of the pot. This is a very slow process and we would expect that the concentration of colour would be most intense around the leaves and then fade out gradually with distance from the leaves. We would not expect ‘wisps’ nor lines of tea, that suggests something else.

It suggests the third mechanism of the tea brewing: a mix of diffusion and then convection within the hot water of the pot. The lines of tea are indicating that within the cup, regions of the hot water are at slightly different temperatures. Owing to the hot water being in contact with cooler air surrounding it, the surface of the water is cooling down and sinking, leading to a convective motion within the water inside. As the water moves it carries the diffused tea with it into new areas of the water, a movement of hot water to cooler water and back again. The tea is carried in a line because the convection patterns are occurring in small cells within the tea pot, small regions where hot tea is moving towards cooler tea which is warmed and itself moves. The convection does not happen as if the hot water is one big mass but a series of smaller ‘cells’. We see similar cells on the surface of the Sun. The lines are telling us of the movement in the tea pot and the amount and speed of their movement reveals more about how hot the water is relative to the air outside the pot.

diffusion only
A tea bag in cold water: This time, there are no wisps of tea as the drink brews. Instead, there is a slow diffusion of tea infused water from the bag outwards.

Testing this idea I required tea bags. My tea pots are opaque and so would not help me to appreciate this detail of brewing a cup of tea and so it was back to the bag-in-cup method. However, in order to avoid turbulence, I poured the water (hot or cool) into the mug before adding the tea bag. It was not the best way to make a tea, apologies to tea lovers, but it was a tea that I do not enjoy anyway, so it was good to use it up. Sure enough, when the tea bag was put into the hot water, within a very short time, wisps of coloured water formed lines curling underneath the bag. Why did they flow down? Was it because the tea in the bag was slightly cooler than the hot water and so, as the tea diffused out of the leaves it moved with convection downwards because of gravity and the fact that cooler water is denser? A tea bag in cool water however behaved differently. The water in the cup had been taken from the tap and then left in the cup for a couple of hours so that the water was definitely at the same temperature as the room. This time, the tea bag first floated and then sank to the bottom of the cup. There was no obvious infusion of the tea-coloured water into the plain water but slowly the region around the bottom of the tea cup at the bag turned browner with the tea. As time went on, this region expanded to give a tea layer and a water layer.

The wispy lines of tea only happened when using hot water. Which suggests a further experiment. How do these wisps change when brewing for black teas as opposed to green teas (which use a lower brewing water temperature)?

After about five minutes the tea brewed in hot water (left) was fairly evenly distributed throughout the cup whereas the tea brewed in cold water (right) showed a distinct layering between concentrated tea at the bottom of the cup and plain water above that layer.

One last observation with these tea bags in the hot water. Some of the tea floated within the bag, some sank, as time went on, more tea leaves fell towards the bottom of the bag (which was itself floating). What was happening there? Maybe if you experiment with your tea, you can let me know in the comments below, on Twitter or on Facebook. There are definite advantages to slowing down and brewing a proper cup of tea.

Categories
Coffee cup science Coffee review Science history Tea

Schrodinger’s Katsute (100), Angel

Katsute 100, tea in Islington
It was a sunny day when we visited Katsute100 in Angel, Islington

When Bean Thinking started, it was always going to be about coffee and yet, Katsute 100 is definitely a tea place. Not only that, but the idea was to see how the physics that we use to describe our universe is mirrored by the physics of the coffee and in a cafe, the physics of the every-day. On the other hand, the whole point of Schrodinger’s cat is to demonstrate how aspects of quantum mechanics are absolutely unlike our everyday experience: a cat both (and neither) dead and alive? And yet, without giving too much away, today’s cafe-physics review is absolutely this – a review of a tea house that features the famous thought experiment. How far Bean Thinking has moved!

Katsute 100 is a welcoming, and peaceful, Japanese tea place in Angel. With a full tea menu and some really great desserts, it is definitely a good place to spend half an hour, maybe more, watching the coming and going and exploring the tea. And there is certainly a lot of tea to explore, different tasting notes revealing themselves as the tea cools, the carefully placed tea pot and tray adding to the experience.

The shop itself is fairly narrow, decorated in sympathy with the Georgian age of the shop itself and with a view into a garden at the back. Japanese tea making equipment is displayed (and for sale) on the various wooden cabinets around the shop. My tea had been buttery (exactly as it had been described in the tasting notes) and the Ichigo Daifuku I had had with it was a fascinating exploration of texture. There were some Japanese art works on the wall and it was then that I saw my first one: a cat. Not a real one of course but one of several decorative cats that are, almost hiding, around the shop. The word “Katsute” has nothing to do with cats apparently meaning “once”, but nonetheless, a few cats do pop up here and there. And even where cats don’t pop up, there are drawers in the wooden cupboards that seem much like boxes, is there a cat there in the box? Is it dead, alive, both, neither? What does this even mean? And is it connected to Katsute, “once”, after all?

note the pouring slits on the teapot
Tea pot, tea cup and ichigo daifuku at Katsute 100

Looking carefully at my teapot, three grooves were carved into the spout allowing the tea to flow out. Each stream of complex flow interferes with the neighbouring stream to present an aesthetic of flowing liquid to match the sound and flavour of the tea. And of course it is reminiscent of an experiment that is key to the unfamiliarity of quantum physics: the double slit experiment.

When light (of a single wavelength, such as from a laser) is shone at a sheet with two holes in it, the light that has travelled through shows interference fringes and patterns. Indeed, it is one of the experiments that went to establishing the theory that light was a wave (and not, as Newton among others had thought, a stream of particles). The situation is quite different if you tried to pass particles through two slits, imagine a sieve with two holes and a stream of coffee beans travelling towards it, we’d expect each bean to go through one hole or the other, not both. In classical physics that’s what we would expect too and yet, when sub-atomic particles (such as electrons) were aimed at two slits and made to travel through them they interfered with each other, as if they were not particles but waves. But other experiments had shown conclusively that they were also particles and indeed, when each individually hit the detector it did so as a single spot, as a particle. Particles and waves? What was going on?

cupboards in Katsute 100
A lot of sake and a fair number of drawers. But what is behind each drawer and why is one missing?

In fact it was a result that had been predicted: Louis de Broglie had shown, theoretically in 1923, that all particles should have wave-like properties and simultaneously, that all waves should have particle-like properties. We should expect that under certain circumstances, light, electrons, neutrons etc, even atoms, should behave as particles and under certain other circumstances (such as the double slit experiment) as waves. But there was an important catch. The electron travelling through a double slit will behave as if it is a wave, passing through both slits and interfering with itself to produce the characteristic “diffraction pattern” of a wave but only if we do not try to look at it to see which slit it really passed through. If we try to detect which slit the particle has travelled through, we can indeed find that some of the electrons travel through one slit and some through the other but when we look at the resulting interference pattern it is gone! What we are left with is the (classically expected) pattern of two particles going through two slits exactly as if they had been very small coffee beans. (You can see a video of Jim Al-Khalili explaining this peculiar result here).

What is going on? To a certain extent, this question is part of the reason that quantum mechanics can seem so strange. We can’t really ask what is going on, or rather, if we ask, we cannot expect to get an answer! We can describe what happens and we can make predictions based on the mathematics that we use to describe the processes. Our technology and our understanding of physics has developed hugely because we can describe how things will behave. But we will stumble if we try to understand what is really going on behind these processes. As Feynman said in lectures he gave to physics undergraduates:

“We cannot make the mystery go away by ‘explaining’ how it works. We will just tell you how it works. In telling you how it works we will have told you about the basic peculiarities of all quantum mechanics.”§

And so things remain enigmatic. Questions that appear to show paradoxes such as the problem of Schrodinger’s cat* continue to puzzle and intrigue us. Is the cat dead or alive? Can the cat be both? Is the cat an observer and what role does the observer have in physical measurements? What does this imply for the fabric of reality? And is there a connection back to the name of this cafe, “once”?

You perhaps should not expect to find any answers in Katsute 100, but pondering these things with a good cup of tea may help advance your understanding. It will certainly help advance your mood if you are in need of some peaceful, thoughtful, time out.

Katsute 100 is at 100 Islington High St, N1 8EG

§ Feynman Lectures on Physics Volume III, 1965

*The story of Schrodinger’s cat is that a cat is placed in a box together with a small amount of radioactive source material. The box is then closed and we cannot see inside. The amount of radioactive material is such that in one hour it has a 50:50 chance of decay. If the material decays radioactively, it triggers the release of a vial of poisonous gas which would kill the cat. Our mathematical models of quantum mechanics suggest that, until it is measured, the radioactive material is in a ‘superposition of states’: it has both decayed and not decayed; the cat is both dead and alive. Only when we open the box after an hour and thereby measure the state of the radioactive material does the cat, at that point, ‘collapse’ into a state that is either dead or alive.

Categories
Coffee review Observations slow Tea

Rosie and Joe, St Giles churchyard

Coffee in a Wake Cup at Rosie & Joe in St Giles. The space rewards those who notice.

There is a long history of hospitality on the site of St Giles in the Fields stretching back far earlier than the Notes coffee barrow. But Rosie & Joe is a lovely iteration to that tradition. There’s a definite focus on tea at Rosie & Joe but the coffee is roasted by Square Mile and prepared on a La Marzocco machine. There is also a good selection of food to nibble on (as well as more food stalls nearby on weekday lunchtimes). And although it is a cart, there are a few seats and tables dotted around so it is easy to sit back and enjoy your coffee while the world races by.

St Giles High St is a very busy road and yet, sitting in the churchyard of St Giles is strangely peaceful. Despite the traffic and the occasional siren, it is one of those rare places in London that you can find the stillness to listen. A beautiful place to enjoy a coffee from an independent stall in fact! And if you have your own cup with you, there is even 10p off your coffee. The coffee was smooth and sweet, fruity but definitely a sweet and full bodied type of fruity cup. But why was it so peaceful? Was it merely that it was a lovely (but breezy) spring morning when I tried Rosie & Joe? Or was it that it is a small bit of nature in a built up environment? Both of these helped but I think it is also the way that the place rewards those who notice by offering more each time you look.
The ghost sign hidden behind the tree just outside the churchyard.

There’s the, perhaps slightly grim, history suggested by the fact that the ‘garden’ is significantly raised above the level of the pavement in parts. There’s the brickwork and stone walls of the church itself of course. The ‘ghost sign’ on a nearby building that is revealed to the coffee drinker by the fact that the tree between us and it has not yet got its summer leaves. And then the nod to the history of the site hinted at by the coffee cart itself: Since Matilda, wife of Henry I founded St Giles’ leprosy hospital on the site, a “cup of charity” was given to condemned prisoners as they made their way past St Giles on their way to their execution at Tyburn*. Very different now, but the tradition of refreshment for the traveller is continued.

But then a fire engine’s siren reminds you that you are in a cosmos, a universe filled with beautiful physics. You know whether the fire engine is approaching or has passed away from you from how the pitch of the sound changes as it goes past. The Doppler shift meaning that sound waves travelling towards you have a shorter wavelength (higher frequency, higher pitch) than those travelling away (longer wavelength, lower frequency, lower pitch). And part of the beauty of physics is that it is so universal; what works for sound also works for light. If an object emitting light is moving away from us, the light appears to have a longer wavelength (lower frequency, it is red-shifted) than if the same object were stationary or moving towards us where it would appear as if it emitted light with a shorter wavelength (higher frequency, blue shifted).

signboard at Rosie and Joe
Doesn’t a right imply a duty? There’s a lot that could be said about #supportindependent
So, similarly, if we were to look at the surface of a rotating planet and saw how the light reflected off that planet’s surface, the side of the planet that was rotating towards us would look ever so slightly bluer than the side rotating away from us which would look slightly redder. And if the planet’s surface was like Venus and obscured by clouds (rather like the ghost sign at Rosie & Joe will be obscured by leaves in a couple of months time) we could use the reflection of radio waves from the surface rather than visible light to see the same red-shift/blue-shift in the radio waves as the planet rotates**. In this way we could determine the direction of rotation of the planet and how fast it was rotating just as we get an indication of the speed of the fire engine from listening to the sound of the siren.

The siren takes us from a consideration of inner stillness to a recognition of the scale of the universe. Which is rather apt for a cafe in a churchyard, where the architecture of a church is often designed to be read symbolically, from the person to their place in the grand scheme of things***. One great thing about this particular cafe though was how much there was to see that cannot be included in this cafe-physics review for reasons of space. The location truly rewards those who pay attention to what they notice here. I can only recommend that you take some time out, take your re-usable cup and go to find some time to enjoy your coffee (or tea) in this quiet space in central London.

*The London Encyclopaedia, 3rd Edition, Weinreb et al., 2008

**Astronomy, the evolving universe, 6th Edition, Zeilik, 1991

***How to read a church, Taylor, 2003

Rosie and Joe can be found in St Giles in the Fields churchyard, Monday-Friday.

Categories
Coffee review General Observations slow Sustainability/environmental Tea

To stay or to go at Cafe from Crisis

coffee commercial St volcano
Cafe from Crisis on Commercial Street, E1. Notice the arches…

It was not what I had expected. Entering the door of the Cafe from Crisis, you go up a ramp with a bench running alongside it before the counter looms in front of you with a large café space opening up to your right (previously partially obscured from your view by the wall for the ramp). Perhaps it is fitting that my expectations were wrong. Many of us have ideas about the homeless (why they are homeless, what homelessness is etc) that may not match fully with the reality. And this café is, after all, in the head office of Crisis, a UK national charity working with the homeless and homelessness.

The coffee is roasted by Volcano and there are a large number of food options (including vegan and veggie) and cakes at the counter. A selection of keep cups are also arranged in a rack on the left of the counter, should you not have one yet. We ordered an Americano and tea (to stay) and took our numbered wooden spoon to the table so that they could find us. Although it was late lunchtime and busy, the drinks arrived fairly quickly with the coffee in a (Crisis themed?) red cup. Apparently serving coffee in red cups make us perceive the coffee as warmer than if it is served in a blue cup. Whether this is true or not, the warm brew was very welcome on this cold January day. The café is situated on a street corner which means that it has many windows, each topped with a shallow arch. The building looks fairly modern from the outside, but the arches were reminiscent of the way that older buildings can be dated by the window style, along with other features. The Cure played in the background which entertained my tea drinking companion but made me wonder about the ideas of Pythagoras on the psychological impacts of different sorts of music (and whether it affected the ability to find thought connections in a café).

plant in a coffee cup
It turns out there are many things to notice in this photo. From the bricks to the self-defence tactics of plants. But what about the nature of the home of the plant?

As we sat, enjoyed our drinks and looked around, we noticed that some plants had found a home in coffee cups placed on the tables around. Small plants in plastic pots (a nod to the anthropocene as pointed out by @lifelearner47 on twitter) were dotted around the café. Did they move from an espresso to a long black cup as they grew larger? Perhaps it was the spiky plant in one of the pots, but my mind immediately jumped to hermit crabs and their search for a new shell each time they grew a bit bigger. Marine hermit crabs  have been shown to be happy in any old discarded shell. Normally these are the ex-homes of gastropods that have, well, “moved on” would be a euphemism, but marine based hermit crabs have been known to make their shells out of all sorts of things including our plastic litter. Land based hermit crabs however are far more demanding and only move into shells that have been specially remodelled by earlier generations of hermit crabs for their own use. This means that land based hermit crabs have to develop a social awareness of other hermit crabs when they want to swap shells.

Apparently the interaction goes something like this: A group of hermit crabs come together in a small-ish area and begin to scope each other out. The loose collection becomes a cluster as the crabs explore whether one of the larger crabs can be evicted from its shell. As the process of eviction is about to occur, the remaining crabs (which can number quite a few, 10 or more) literally ‘line up’ in order of shell size so that, when the largest is evicted, each crab can move up to the next sized shell leaving the smallest, most undesirable shell on the seashore and the poor evicted crab, shell-less.

Several questions arise but one is, do the crabs make decisions, “to stay or to go” based on how advanced the eviction process is? So, say a crab wanders into an area with an unusually large number of crabs in it (perhaps 4) but the crabs are all lined up in a queue ready to swap into each others shells. Do the crabs coming into the area stick around for a long time or do they head off somewhere else? Or, conversely, what if they enter an area where there are more than the usual number of ‘colleagues’, but they are all scattered about, not yet ready to evict the largest crab. What would our incoming crab do then?

coffee red cup Crisis
What would you learn if you noticed the connections your mind was forming while enjoying a coffee?

These questions were addressed by a group working with the terrestrial hermit crabs of Costa Rica. By defining five cells on the beach, each with a different arrangement of (empty but inaccessible) shells that the incoming hermit crab may want, the researchers found that the incoming hermits were making some strikingly sensible decisions. When the crab came into a region of scattered shells (that the incomer mistook for fellow crabs owing to a trick with a combination of loctite glue and partially burying the empty shells that the researchers used to fool the incomers), the incomer tended to stick around, waiting for an opportunity to swap a shell. If the incomer came but saw that the queue of shells had already formed, it still stayed a bit longer in the region relative to a control area devoid of shells, but it did tend to leave it after some time, perhaps to look for new shells elsewhere. The researchers concluded that when the crab came into an area and thought it had a pretty good chance of inserting itself into a good queue position, it would stay in the area waiting for the eviction to occur and the shell swapping process to start. However when the crab came into an area where the queue had already formed, it was unlikely to be able to get a good position in the queue and so would investigate the situation for a bit before wandering off elsewhere in the search of a new shell in a different area.

Does this have any relevance to a café trying to do a bit to address the problems of homelessness and the homeless in our city and country? I will leave that to each reader to ponder. However, it was a great opportunity to learn something new about our world, which only happened because I stopped to notice something in a café and then wondered how hermit crabs get their homes. It’s always good to slow down and notice things. What will you see next?

Cafe from Crisis (London) is at 64 Commercial Street, E1 6LT.

Categories
General Home experiments Observations slow Tea

Corona gazing in cafes

interference patterns on coffee
There are many ways in which rainbows of colour are produced as light interacts with our coffee or in a cafe. Looking around yourself now, how many do you see? What physics underlies each?

As the nights grow longer and the days colder, we notice that windows steam up as the water vapour in the café condenses onto the cooler glass. Perhaps we see a similar thing on our glasses while we are drinking tea or on the windows of a bus. Initially we perhaps become frustrated at our inability to see what is going on outside but then we notice the colourful patterns around the lights of passing cars and of street lights. Haloes of coloured light around a central bright spot. What does this tell us and where else can we see it, either in a café or in life generally?

On a window pane, a large number of small droplets of water have condensed into what appears to us as a fog on the glass. As the light shines through from the car headlights, each droplet acts as an obstacle to the light and so bends it. You could see a similar effect with the waves on the sea going around stones or perhaps if you brew a large cup of coffee with the surface waves going around a spoon (let me know if you manage to see this bending in a coffee cup). The amount that the light bends is dependent on the wavelength of the light (look carefully at the waves going around obstacles in ponds to see this) and so different wavelengths (different colours) get bent by different amounts and interfere with each other at different points – a spectrum is produced. It is a phenomenon known as diffraction.

Not all beans are equal! How could you quickly distinguish between arabica and robusta beans?

This phenomenon means that we have a way of separating the frequencies (or wavelengths) of light. And so this means that we have a way of measuring the chemical composition of some substances as different chemicals absorb different frequencies and so have ‘fingerprints’ in the light they scatter. By passing the light scattered from a substance (such as arabica coffee beans compared to robusta) through a diffraction grating (which is an obstacle with a pattern of fixed size), we can separate the frequencies being scattered and see if any of them are ‘missing’ (ie. they have been absorbed by the material we’re studying). It would be  a bit like looking at that rainbow pattern in the café window and not seeing blue, its absence tells you something. This is one of the ways that robusta beans can be quickly found if they have been substituted for arabica beans in coffee trading.

Coffee Corona
Look carefully: Sometimes you can infer the existence of a thin (white) mist over your coffee by the corona pattern around reflected light fittings.

But it is not just its technological aspect that has interest for us surely? When gazing at the moon on a misty evening, the halo around the moon suggests the clouds between us and it. It is something that poets have remarked upon to evoke atmosphere, it is something that we can gaze at as we imagine the giant café window of our atmosphere. But the size, and distinctness of the lunar corona actually give us clues about the droplets making up the cloud. And then we look closer to home and to our own coffee and we see the same diffraction pattern again looking back at us from our coffee’s surface. Occasionally it is possible to see haloes on the coffee surface around the reflection of overhead lights in the café. A coffee corona! This reveals to us the fact that there are droplets of water above the surface of our coffee; an extra layer of hovering droplets. Something that we can sometimes see more directly in the dancing white mists.

Diffraction is a beautiful phenomenon that allows us to gaze and to contemplate how much we are able to deduce and how much we have yet to understand. How atmospheric our coffees and cafés are and the journey of understanding that we have taken to get to this point. Coffee gazing is a hobby that should be taken up by far more of us.

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Categories
Coffee review General Home experiments Observations Science history slow Tea

Noticing at Artisan, Ealing

coffee Artisan Ealing
A good coffee is a solid foundation for any afternoon’s noticing.

A cafe-physics review with a difference. In that, it’s not so much a review as an invitation. What do you notice in a café?

Last week, I had the opportunity to try Artisan’s Ealing branch. Although I had found a lot to notice on my previous visit to the East Sheen branch, I had a very specific reason for visiting the Ealing location of this small chain of four cafés. The coffee (espresso) was reliably good. Smooth and drinkable in a friendly atmosphere. Just as with the café in East Sheen, there were a good selection of edibles at the counter and plenty to notice. The light shades were immediately outstanding as something to notice while a framed ‘hole in the wall’ provided a conversation point. The café was very busy and while there was plenty of seating with many tables, we were still lucky to have got a table for two near the back. Behind us there was a lesson going on in the coffee school while on the wall was the calendar for the space booking downstairs. And it was this that I had come here for.

A couple of months ago, Artisan announced that this space would be available to rent to provide a friendly space (with coffee) for the meetings of local small businesses or charities. This stayed in the back of my mind for a while as it came about at roughly the same time as an idea for Bean Thinking.

Lampshades at Artisan Ealing
First the obvious. Immediately striking, these lampshades could provide several avenues for thought.

There are a couple of us who are interested in meeting, about once a month, to discuss science. As ‘science’ is quite a big subject, we thought we would limit it to science that is associated with coffee or with the café at which we are meeting. Perhaps readers of this website may realise that this is not such a restriction, it is quite easy to connect coffee to the cosmic microwave background radiation of the Universe or to chromatography and analytical chemistry. If we were to meet in a location such as Artisan, there should be plenty more food for thoughts. The lampshades prompted me to consider what made substances opaque or transparent? Where is the link to coffee and methods for measuring the coffee extraction? The hole in the wall suggested thoughts about the algorithms behind cash machines. I’m sure that there is plenty more to notice if we take the time to see it.

And so this is an invitation. Would you like to join us in exploring what we each notice about the science of our surroundings? The plan would be to meet once a month, probably starting late January 2019 or early February (date and location to be confirmed). An afternoon on the weekend is probably better than an evening and we’d probably stay for an hour or two. You do not have to be a practising scientist to come along indeed, it would be great if we could have people from a variety of walks of life. The idea is not (necessarily) to answer scientific questions that we each may have but instead to explore the science behind the questions, to find the connections that form our ideas of the universe. To really notice our surroundings and our coffees (tea drinkers would also be welcome). As a consequence of this, mobile phones/laptops etc. will be discouraged during the afternoon. We’d like to notice things around us and not be distracted by what a search engine suggests about it; if we think a search engine could help us, we’ll use it after we’ve left and come back the following month to discuss the issues further. So, if you are curious, would like to explore what you notice and can tolerate keeping your phone on silent and in your pocket for an afternoon, please do come along, it would be great to meet some of you.

menus and lampshades in Artisan
You may like to look more closely at this photo. How are the menus supported? What does that tell us about the history of science?

In order to understand whether there would be any interest in this idea and to hear your input about the format, content, location, time etc. I have set up a mailing list for these cafe-science-spaces. Please do sign up to the mailing list to hear the latest announcements concerning these events and also to email me back to contribute your opinion. You can sign up to the mailing list using the sign up form below. Alternatively, if you don’t want to sign up to the mailing list but do want to hear more, I will be advertising the events on Twitter and Facebook so please do feel free to follow me there.

 

Please enter your email address here if you would like to hear about future Bean Thinking events.

 

Categories
Coffee review Observations Science history Sustainability/environmental Tea

A post in need of a Curator(s) Coffee, Fitzrovia

espresso Curators
A deliciously intense and fruity espresso from the ‘specials’ menu at Curators Coffee.

Curators Coffee in Margaret St in Fitzrovia has been there for years. A great location just off of Oxford St, with plenty of seating and good coffee, and so it is perfect to pop into, unless you are like me and avoid the Oxford St area as much as possible. Which perhaps explains the rarity of my visits. I first popped into Curators Coffee a couple of years back (before the laws on allergen information came in) when I remember enjoying a lovely long black but couldn’t have a cake because the people behind the counter that day couldn’t tell me which (if any) cakes contained nuts. At the time, I sat upstairs and noticed the graphene type arrangement of hexagons around the back of the space and the Bramah’s 300 years of coffee makers book in a rack at the back. I had wanted to return to properly cafe-physics review the place at a later date (and try the cake) but circumstances (and Oxford St avoidance) meant that I never got round to it. Until very recently.

This time, I noticed that there were three single origin coffees available to try as espresso. Glancing at the tasting notes it was a fairly quick decision: “chocolate”. And although this time I had just had lunch and so passed on the cake, it appears that the espresso choices regularly rotate, offering an incentive to come back again and try something new. Although the café is quite large, with plenty of seating, it seems that it is also very popular. And so there were no spaces remaining upstairs. Fortunately, there were more seats downstairs and so, taking our table number with us, we made our way down the stairs and found a table at the window, as if it was waiting for us.

UFO in Curators Coffee Fitzrovia
A UFO reflected in the window? Why? What? Why (again)? It is small details such as this that reward you as you put down your smart phone and notice your surroundings.

Perhaps it is obvious that a café called Curators should have art work adorning the walls. That, and the spotlights that highlighted the work immediately caught our interest, (although it was odd to see that one of the rows of spotlights was almost devoid of bulbs). The exhibition downstairs seemed to have a tilt towards street art and a couple of decorated aerosol cans were on the windowsill priced at £15 each. Was this the time to consider why an aerosol gets cooler as you spray the walls with it?

Outside the window, a staircase leading up to the street outside had railings in straight lines leading up towards a blue sky. Inside, a space craft was reflected in the window.

Indeed, on checking again, there was a spacecraft, like a cartoon of a stereotypical little UFO, drawn onto the wall behind my accomplice’s head and reflected in the window next to it. What could it mean? Regardless of whether some UFO incidents are associated with visitors from other planets, there are a large number of scientific thought trains we can take when considering a UFO reflected in a window. To start with, how likely is it that we are alone in the universe or that there are many other intelligent life forms in other planetary systems?

The question has been answered on the basis of probability for many years. But recently, we have been finding more planets orbiting stars and crucially, more planets that are in the ‘habitable’ zone around other stars. Assuming that life elsewhere needs similar conditions to the earth’s in order to thrive, the idea of life elsewhere is becoming increasingly real.

canali Curators Coffee
If you see straight lines such as this, it is fairly sensible to infer that they were built by an intelligent life-form. Can you see canals on Mars?

Closer to home, there were even suggestions that Mars may support flowing water, thought to be a host for bacteria based life. And although these interpretations of the flow patterns observed on the Martian surface have more recently been contested (could they instead be flowing sand?), we continue to send probes (such as the Insight probe that landed recently) to the red planet to investigate its geology. Did Mars once host life?  Mars of course has a resonance in science fiction for being the planet hosting extra-terrestrial life. HG Wells imagined the Martians landing just south of London, and eventually being killed off by exposure to bacteria on earth that they had not experienced in their Martian habitat. Could life on Mars suggest a (tenuous) further link to this café on Margaret St?

Perhaps one reason that people started to imagine (intelligent) life on Mars came about because of an interesting mistranslation of an astronomical observation. While gazing at Mars in 1877, Schiaparelli noted ‘canali’ on the Martian surface. The correct translation of this in this context into English is “channels” but what the observation came to be known as was “canals”. Canals imply an intelligent builder, and hence life on Mars. Later observers also saw these ‘canals’ and a popular myth was born. It is a useful lesson for us all, sometimes how we see something can be influenced by the language we use to describe it.

soya hot chocolate, Curators
We photograph our coffee, and share it with our online friends. But would putting down our phone in a cafe be worth something for the planet as well as for ourselves? How many batteries do we need?

And then one final thought train, prompted by photographing the cafe with my mobile phone. The whole probability argument rests on two assumptions. The first is that there are other planetary systems (which we are finding). The second is that life is fairly easy to start, or at least, that the chances of producing life are not restricted to one planet a short distance away from the Sun; we are not unique. As yet we don’t know whether this assumption is justified but discoveries such as the deep sea hydrothermal vents challenge our preconceptions about the requirements for life and suggest that life could start more than once, and so could very well start on other planets, not just ours. In these vents, bacteria are known to convert what we think of as toxic chemicals into energy in a process known as chemosynthesis without the need of sunlight or other ingredients that we had thought essential to life. Could similar hydrothermal vents on other planets host new life forms?

And in a related way, what is going on with these vents? Is new life being created even now in the deep sea? In which case, what do we think about deep sea mining? If our aim is to reduce our carbon dioxide emissions by using more re-usable objects and renewable energy sources, we will require more batteries and batteries require (among other things) cobalt. If we are all to keep using mobile phones to photograph cafés, we too need the batteries which rely on these elements. A number of companies have realised that there is a vast untapped resource under the sea if only we could dredge it up. This may be easier or ultimately cheaper than recycling the old batteries. It may destroy a few hydrothermal vents or stir up the sea bed but what concern is that to us if we can gain access to more cobalt to allow us to have more batteries to allow us to all be ‘greener’.

Indeed, of what concern is that to us?

Curators Coffee is at 51 Margaret St, W1W 8SG

Categories
Observations Science history Tea

The universe and a coffee cup

a heat sensitive coffee mug
Now you see it….

Ordinarily, this week would be the turn of a cafe-physics review but circumstances have meant that this will be postponed by one week, sorry. So instead, a question. How does your coffee cup resemble the universe?

A few years ago, I was given a heat changing mug that revealed the constellations when the coffee within it was hot (and went black as the coffee was finished/went cold). Although this is not the way that the universe resembles a coffee mug, the science behind these mugs is quite interesting and they do provide a clue to the connection. The answer (or an answer, you may think of more) is in the way that the mug emits heat.

On a cold day with a hot coffee, I can be fairly sure that by putting my hands quite close but not touching the cup, I can feel the radiated warmth. Infrared waves helping prevent my fingers from becoming numb. Although there is air around the cup (even physicists don’t drink coffee in a vacuum) and so there will be heat transferred from the cup to my hands via conduction and convection, a large amount of the heat my hands receive will be radiated. It was by watching a candle flame between himself and a stove that Carl Wilhelm Scheele (1742-1786) inferred the presence of the infrared. For a coffee temperature of 60ºC (333 Kelvin), the cup would emit a range of light with a peak in intensity at a wavelength in the infrared of around 8.5 μm, about the length of a grain of espresso grind. The way that objects radiate heat is well known. Called a “black body spectrum”, all things radiate a spectrum that can be approximated to it, whether the object is a coffee cup or the universe, the difference is over what frequency range (or wavelength) the object radiates and where in the spectrum the light intensity peaks.

cold mug
Now you don’t.
The same cup as above but photographed when it is at room temperature not when it contains hot liquid.

Coffee emits light (in the infrared) at 8.5 μm because it is about 60ºC. A ‘red hot’ iron rod, still emits light in a spectrum that peaks in the infrared but appears more red than my coffee cup because the peak in the radiated intensity has decreased closer to the red region of the visible spectrum. The universe emits radiation over the same sort of blackbody curve but the spectrum emitted by the universe peaks at a wavelength of around 2cm, much longer than the coffee cup and well beyond the infrared. In fact, the universe is emitting light in the microwave region. The longer wavelength means that the universe is a lot colder than a cup of coffee. About 330º cooler in fact because the temperature of the universe is a chilly 2.7K (or approximately -270ºC).

The presence of this microwave ‘background’ was first detected in the 1960s. Further experiments in the 1990s with the COBE satellite and more recently with the Planck satellite have confirmed the almost perfect uniformity of the blackbody spectrum. No matter which direction you turn your microwave antennae to, you pick up the same background spectrum, peaking at about 2cm, all around the universe. This means that the background temperature of the universe is the same in all directions that we look, it is uniform. Indeed, it took until the sensitivity of the Planck satellite and more recently the WMAP data to show that the universe had any variation at all. And when it was revealed, it was a difference of about one part in a million. If we compare this to our coffee we can see from the lines of light that dance on the bottom of a tea cup that there is significant temperature variation within the cup. Even a difference of one degree would lead to a shift in the blackbody spectrum of the coffee cup by a few parts in a thousand: the background temperature of the universe is far more uniform than the temperature of your cup of coffee in fact the shift seems to be of the order of 0.0002º.

But, apart from an interesting curiosity why would we want to measure the temperature of the universe or know the uniformity of a cup of coffee? One reason is that knowing the current temperature and its likely cooling mechanism, means that we can calculate how long the universe, or coffee, has been cooling. If I were to drink a cup of coffee that was cooler than about 60ºC I would know that either it has been prepared much earlier and left on the counter top or that it had been prepared using water below the optimum brewing temperature. If I note from the lines of light crossing the bottom of the cup that there is a lot of convection going on in my tea cup with cells of different temperature, I could think that it is either a very cold day or that I didn’t warm the cup before I poured the coffee or tea into it.

NASA image CMB
There is even more information in the background if we start to look at the polarisation of the microwaves. The Cosmic Microwave Background showing the minute temperature fluctuations and polarisation directions. Image credit ESA/Planck Collaboration

Knowing the temperature of the universe allows us to check theories of how the universe formed (and therefore how it cools) by calculating its age and seeing if this matches with the age deduced by other means (by looking at the oldest star clusters for example). While looking at the minute temperature variations across the universe is also a test of the theories of the universe’s formation.

There are clearly differences between the universe and a mug of coffee, even a mug that shows the constellations of the stars, not least the fact that the coffee cools into the universe but the universe’s cooling is different having nothing to cool into. Nonetheless, it is remarkable that the same physical laws and mathematics that describes your cooling coffee cup can be used to describe our entire universe. So sit back, take a deep breath, and enjoy the universe through your coffee cup.

 

Categories
Allergy friendly Coffee review Observations Tea

Hear no evil… at the Inverness Coffee Roasters, Inverness

Coffee in Inverness
Inverness Coffee Roasting Company.

Hear no evil, see no evil, speak no evil, so the saying goes and so the monkey, that was sitting on the sofa at the Inverness Coffee Roasting company (and café) indicated. And while I would not like anything evil to be said on this website generally, today it will be taken to an extreme as this cafe-physics review will not say much at all. Not because the coffee was not good, my Americano was a lovely complex dark and very enjoyable brew. Nor because there weren’t things to write about, several avenues suggested themselves for a ‘cafe-physics’ type review. There were also plenty of things to enjoy nibbling on while sitting down in this warm and comfy environment taking in the surroundings. Chocolate from The Chocolate Place was clearly labelled (and so I could enjoy it confident that it was nut-free) with a good variety of interestingly flavoured chocolates. The chocolate/coffee combination always goes well and the salted dark chocolate indeed complemented the coffee. A variety of freshly roasted coffees were in jars ready for selling to the home-brewing crowd and I heard both people behind the counter discussing coffee tastes with different customers to ensure that they could properly recommend a coffee for each of them.

So why, if the coffee was good, the service friendly and the environment interesting am I not going to write much about Inverness Coffee Roasting Company? Well, largely because I had been on holiday and so the preoccupations of the days before would necessarily influence what I noticed about this little café. Although I could happily write about neolithic monuments and considerations about inter-generational solidarity in relation to the re-use of refuse heaps at Skara Brae (as building material) and our own use (or misuse) of refuse in our environmental behaviour today. And it could even fit into a cafe-physics review of this venue as a sign on the wall above the door invited everyone to join the Plastic Free Scotland movement. However, it is not really what a Bean Thinking cafe-physics review is about. The idea behind the cafe-physics reviews is that things are often connected in surprising and beautiful ways and we can generally only see the connections if we slow down and look for them.

hear no evil, see no evil, speak no evil
Monkey on a sofa, but there was much more to notice at the Inverness Coffee Roasting Company if you looked around you.

Therefore, while you may (or may not) prefer to read about my holiday considerations of all things thousands of years old, what I thought I’d do with this café review is suggest a few things that I noticed in the café, things that offered a variety of potential thought-trains and then see what you think, what you notice, what you see (or don’t see). Perhaps you will observe something in one of the photos that clicks into a thought train for you, perhaps you can look around you, wherever you are right now – and think about the connections you could make to things you sense there instead? But whichever you do, it is a great time to sit back with a coffee (or perhaps a tea), breathe in and take in your surroundings.

Back in Inverness, the first thing of course was the monkey. Eyes shielded with an arm, suggestive of those who would prefer not to see what is in front of them. Nancy MacLean in “Democracy in Chains” notes that a training in the humanities perhaps opens students to question their society more than other, more utilitarian, subjects may do. Is it hurt pride that makes me rebel against this idea? Can’t physicists question too?

Perhaps it is connected but a sign by the door, and an identical one by the sofa, was written on the glass front of a box of coffee beans: “in emergency break glass”. This suggested so many avenues for exploration to me, I wonder which occur to others?

Behind our seats, a lizard was painted on/engraved into a stone, suggestive of fossils, geology and how we collect evidence. But a second lizard suggested a different direction. An ornamental lizard was positioned as if climbing up the counter. How do lizards climb? What is it about their feat? What connects lizards to a coffee company? Above our heads and above the door, stereotypical of Scotland perhaps, loomed a deer head complete with antlers. But this one was different: it was made of coffee beans and string. How a bean based diet could replace a meat one? The nature of units and how it would not necessarily be sensible to measure the mass of a deer in units of coffee beans? The mind jumped. Jumping beans?

Deer head in beans
Bean there done that?
Gruesome ornament or vegan friendly?

Finally, the logo of the cafe which was featured on signs around the interior and exterior of the space: a flaming coffee bean. The Maillard process and the changes in coffee as it is roasted? The nature of heat/temperature and the manner in which we measure it? What we hear as fire burns, lightning bangs or on “the first crack” of roasting and what this tells us about our atmosphere, our planet and our coffee is made of?

Whatever you notice, please get in touch, either by Facebook, Twitter, leave a comment or send me an email. But one last thing on coffee thought trains that links to real trains and is perhaps reflective back onto what it means to pause and watch. We left Inverness the day after our visit to Inverness Coffee Roasting by train. Inverness station has a relatively steep (1:60) gradient for 20 miles on leaving the station. It is Scotland in autumn, it had been raining and leaves had been falling on the line. Five or ten minutes out of the station, our train to Kings Cross juddered and came to a halt. A signal failure apparently. As the driver re-started the train, it slipped backwards, and again. We weren’t able to get up the hill. And so we had to return into Inverness station. Once back at Inverness station, the guard came across the tannoy and suggested that the signallers had given us the go-ahead to ‘have another run’ at the hill to see if we could get up it this time. So we tried again, juddering and shaking to a stop a few hundred metres beyond where we had stopped before. Back to Inverness station it was. The ever hopeful guard came across the tannoy again: “Third time lucky, fingers crossed”. This time the train left the station faster, building up speed, moving along more quickly and powering out of the station. The carriage was silent, were we going to make it? Past the first point we stopped at, past the second, a bit further, the family behind clapped, the train continued then slowed down and shook, juddered and then sped up again. We were over the hill and on our way back to London.

A last consideration on the conservation of energy and its relation to coffee and thought trains? Or a metaphor for how we may not find those connections in that cafe come to us quickly but if we persist and keep noticing, we can go on a fascinating journey?

Do let me know your thoughts.

The Inverness Coffee Roasting Company can be found at 15 Chapel Street Inverness, IV1 1NA