Month: May 2017

Categories
Coffee review General Home experiments Tea

Communities at Wilton Way

exterior of Wilton Way, Hackney Coffee
Wilton Way cafe on Wilton Way

There are two things that may strike you as you walk past Wilton Way café. The first is the prominent La Marzocco espresso machine on the counter. The second is the “ON AIR” sign in the corner next to the window. Indeed, it is best to look out for these two as there didn’t seem to be any other sign indicating that this café was the Wilton Way cafe, home to the London Fields Radio that is broadcast from here (hence the “on air” sign). In the late afternoon, the café offered some shade on a sunny day and so we popped in for a tea, though there is seating on a bench outside should you wish to enjoy the Sun. Although this website is supposed to be about coffee (which is roasted by Climpson & Sons), sometimes a fresh mint tea is what is needed. This particular mint tea was very refreshing with plenty of mint leaves in the cup. Sadly though, in what seems to be a common pattern at the moment, this was another café at which there were few cakes on offer, presumably as it was late afternoon by the time we visited. However, what is sad for the mind is perhaps good for the waistline, we’ll have to revisit in the morning for the cakes next time.

Corrugated iron supported the counter while the (plentiful) seats inside the café appeared to be made of recycled wood and boxes. Interestingly, this is mentioned in the description of the Wilton Way café on the London Fields Radio website, apparently the interior was designed to be a mix of modern and reclaimed materials. Choosing a seat at the back allowed us to survey the space and people-watch while sipping the tea. On the counter was an old-style Casio cash register while in the far corner at the front of the café, the microphone and broadcasting equipment stood waiting to be used for the London Fields Radio.

the broadcasting equipment at the WW cafe Hackney
London Fields Radio, broadcast from Wilton Way cafe

In the book “Radar, how it all began” the author, Jim Brown reminisced about how he had played with a crystal radio set as a child in the 1920s¹. Many scientists can remember making their own radio sets as children (or indeed as adults). It seems playing with things, taking them apart and building them again is part of the personal-history of many scientists and engineers (particularly experimental ones whether they be ‘professional’ scientists or not). The Lunar Society (which was active at the end of the eighteenth century and into the early nineteenth) featured a group of keen “tinkerers”. These were people who experimented with nature and invented new devices in order to explore their understanding of the world. Though each of them were only doing science ‘on the side’ as they each had other day-jobs, individuals within the group did make some important contributions to our understanding of the world. One such contribution was by Josiah Wedgwood who by observing the “waviness of flint glass” noticed its resemblance to “that which arises when water and spirit of wine are first put together before they become perfectly unified”². The reference is to mixing fluids of different density. Isn’t this experience of tinkering with things similar to our enjoyment and appreciation of coffee? The more we experiment, the more coffee we try (including cupping coffee as with this how-to from Perfect Daily Grind), the more deeply involved in coffee we become and the more we value it. Isn’t it actually true that in order to deepen our relationship with coffee we need to explore it (and experiment with it) more fully? Cannot the same be said for our relation to our world?

interior of Wilton Way cafe
The view from the corner. Spacious and quirky, the Wilton Way cafe has plenty to offer the coffee (or tea) drinker who wishes to slow down and appreciate the moment.

But then a second thought that, to some extent flows from the first. No development would be possible without a community, each contributor bringing a different talent but each contributing to an idea of a greater good. The London Fields Radio would not be possible without the scientists and engineers who design and optimise the broadcasting (and receiving) equipment. But neither would it be possible without talented DJs and musicians, thinkers, poets and performers to give us something to listen to. Two more groups of people are needed for London Fields Radio to be a success. Those who provide the space for the broadcasting equipment (i.e. the café) and those who listen in. Again there is an analogy with coffee. No cup of coffee could be there for us to enjoy without the farmers, the traders, the roasters, the baristas and finally many other people like us who enjoy a good cup. And the more each of us tinker with appreciating another’s work (cupping the coffee like a roaster or tending an allotment to appreciate the growth), the more of a community we become and the better coffee we get for it. We do not imagine while ‘cupping’ coffee that we are really about to take on the role of the coffee trader or roaster, yet by playing at their job we can appreciate their importance and skill more and so realise more effectively our own role too. We could go full-cycle here and consider how playing with radios and experiments can help us to understand the role of technology and science in society and our participation in it, but perhaps that is left as a point to ponder in another café: How can we each contribute to a better society, understand our role in it and appreciate the contributions of others?

One final thought that came from the Lunar society but appears to have a very contemporary relevance. Wedgwood once said to Richard Lovell Edgeworth “But in politics… as in religion, hardly any two people who thought at all, thought exactly alike on everything.” The main thing was “to agree to differ, to agree on impartial investigation and candid argument”.² It appears the Lunar men still have a thing or two to teach us.

Wilton Way cafe can be found at 63 Wilton Way, E8 1BG

¹Radar, How it all began, Jim Brown, Janus Publishing Ltd, 1996

²The Lunar Men, Jenny Uglow, Faber & Faber, 2003

Categories
Coffee cup science General Home experiments Observations Tea

Developing, a new way to slow down with coffee

“Instant gratification takes too long.”

Carrie Fisher

What do you think of instant coffee? Does it, as Carrie Fisher may have suggested, take too long? Or perhaps you think that instant coffee is a bad idea, coffee ought instead to be prepared well and slowly to be enjoyed at a leisurely pace. Many readers of this website are probably of the latter school of thought and yet I would like to offer a slightly different perspective. There is indeed a way that instant coffee can be used to really slow down and to re-evaluate our view of the world: Instant coffee makes a good, or at least adequate, photographic film developer.

developing photographic film in instant coffee
The developing fluid – the instant coffee granules have nearly dissolved.

The caffeine in the coffee acts as a reducing agent for the film (so tea should also work). Instant was suggested over filter coffee in online recipes owing to the greater control over the amount of caffeine in the brew (it would be far easier to get reproducible results mixing 5 teaspoons of instant into the developer than 300ml of whichever coffee is your brew of the day). So, as a first try, it is worth keeping to previously tried-and-tested recipes, in this case from photo-utopia.

5 heaped teaspoons of instant coffee

2 level teaspoons of washing soda

300 ml of water at around 25C.

washing soda, available in supermarkets
The second ingredient that you need to develop your photographic film in coffee – washing soda.

The washing soda (sodium carbonate, Na2CO3) can be purchased in many supermarkets where it is known as a more environmentally friendly laundry agent (it is not the cooking ingredient sodium bicarbonate, that apparently does not work). It is used to ‘activate’ the reducing agent. I admit to being a bit hazy on what that actually means. Where you get your instant coffee from is up to you.

The photos show the washing soda and then coffee being added to the water. Do try to rid yourself of any ideas about developing film amidst the lovely fragrance of coffee coming out of the developing tank. Something in the reaction between the washing soda and the coffee stinks. It was not as bad as I was anticipating (as I had read the warnings of the smell elsewhere) but rest assured, it is not pleasant!

instant coffee film developing fluid
The washing soda is already dissolved in the water here but the coffee has just been added. You need to dissolve the coffee fully for it to be a good developing fluid.

For detailed instructions about developing with the solution, please see photo-utopia but briefly, developing the film took 30 minutes with one inversion every 30 seconds. If you have ever tried sitting, developing film for 30 minutes doing nothing but inverting the developing tank every 30 seconds you will know that this is quite an exercise in slowing down. Are those images that you have been taking on your camera going to come out? Will they be under-developed, over-developed? Does coffee really work as a film developing fluid?

After 30 minutes the film was put into a water stop bath and then fixed with Ilford Rapid Fixer (although it is possible to use salt-water as a fixer, I thought it best to start by experimenting with the developing fluid alone first). A further bit of washing and the film was hung out to dry. This meant more patience, although we could see the images on the film, it was not possible to scan them until the film had thoroughly dried (we left it overnight).

What about the results? Well, the four images below are from the roll of Fuji Neopan 400 film that was developed with the coffee. We had to adjust the scanning a bit as the film was somewhat lightly developed (a higher concentration of caffeine or a longer developing time was needed), but you can see that the images have not come out too badly. It is truly possible to slow down and see things in a different way with instant coffee, but maybe not by drinking it.

Cogs, Wimbledon Common, Windmill, Contact S2b, instant coffee and washing soda developer
Cogs on Wimbledon Common, developed with coffee.
Brighton shellfish, mussels, prawns, cockles, whelks, jellied eels, instant coffee
Shellfish trailer, Brighton, developed in coffee.
Merry-go-round and pier developed with coffee
Brighton beach, developed in coffee.
Bench with heads developed in coffee
Chelsea Embankment, developed in coffee.

Next time I plan to swap the instant coffee for a brewed batch and see how that comes out. More photos will be uploaded from time to time, probably to a special “coffee pictures” page on the website (yet to be created). And if you have tried developing photographic film in coffee, please do share any images that you have developed (with coffee or tea, instant or otherwise).

I am incredibly grateful to ArtemisWorks Photography for helping with all aspects of this project and for fantastic patience when confronted with some daft questions. You may also be interested to see ArtemisWorks’ own café work, photographing London’s older style “caffs” many of which have now disappeared, the café galleries can be found here.

 

Creative Commons License
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.

Categories
Coffee review General Observations Science history Tea

In the loop at Coffee is my cup of tea

exterior coffee is my cup of tea, cimcot, coffee Hackney
Coffee is my cup of tea on Dalston Lane. The colour of the exterior matches the crockery used inside.

There is a lot of truth in the name of this café. “Coffee is my cup of tea” in Hackney is a lovely retreat, a place where you can take time to enjoy whatever drink is your cup of tea. Walking through the door, you are presented with a few wooden tables and a cocktail menu on the wall. A breath of calm on an otherwise busy road. Together with the bench just outside, there is plenty of seating inside. There’s even a long table along the window where you can sit if you would like to enjoy your coffee while gazing at the passers-by. There were the usual range of coffees on offer along with fresh juices, other drinks together with a range of food. When we went in the late afternoon, there didn’t seem to be many cakes on offer but maybe we were just unlucky. Coffee only this time. The coffee is roasted by Assembly and there is of course tap water available at the end of the bar.

Facing the bar, glued to the wall, were a circle of stiletto shoes. Forming what seemed to  be a “shoe star”, they were one of a number of art works around the shop. The café is also quite spacious, the window at the front providing plenty of light and contributing to the relaxed space. When my long black arrived, the light coming in from the windows produced great interference patterns on the bubbles of the coffee, an irresistible piece of coffee physics. The cocktail menu provided quite a distraction, again making the point that it was a shame we visited on an afternoon: an evening of coffee and cocktails would make a lovely night. However, a sunny afternoon was a great time to sip and enjoy a long black. While the long black started off very fruity, the taste changed (matured?) as the temperature of the coffee decreased. In the background to this all though, something so subtle as to be almost un-noticeable caught my attention. Completely surrounding the window was a very thin piece of copper wire. Were there tiny little lights on it to make the café more attractive (romantic even?) in the evening? I couldn’t see any. From our table, it seemed as if it was just a thin, closed loop of copper wire forming a loop around the window.

coffee cimcot
Fantastic interference patterns on the bubbles of the coffee at Coffee is my cup of tea

Such a loop could be used as a radio antenna, a “loop antenna”. Indeed, when Heinrich Hertz (1857-1894) first discovered radio waves in 1887-8, he used a (gapped) loop antenna as the receiver. Hertz had been trying to test James Clerk Maxwell’s theory that visible light was part of a much broader spectrum of electromagnetic waves, particularly, that there should exist very low frequency waves far beyond the visible region of the spectrum, waves that we now know as “radio waves”. Radio, TV, wifi, all things that seem so obvious now but were really only predicted and discovered relatively recently. Working in his laboratory in Karlsruhe, Hertz set up a radio generator which consisted of two brass balls that were charged until a spark flashed between them. Sitting a few metres away, a gapped loop of wire, the ‘loop antenna’ suddenly showed a spark over the gap. The spark that Hertz had generated in one part of the room had been mysteriously transmitted, as if through an aether, to be picked up by the antenna a few metres away. Clearly it was consistent with Maxwell’s predictions. The electric spark had generated a low frequency electromagnetic wave that had been picked up with the loop antenna. With further experiments, Hertz showed that this wave was indeed reflected and refracted in the same way as ordinary, visible, light and even determined its wavelength (which for Hertz’s experiment was about 66cm)¹.

loop antenna at cimcot, Dalston Lane
It is probably easiest if you visit the cafe but look very very closely at the frame of the window. There is a copper wire surrounding it.

Although Hertz did not immediately see any practical application of his result (beyond the fact that it was a test of Maxwell’s theory of light), ‘radio’ soon started to be developed. Marconi and others worked with wavelengths of 200-600 m to transmit radio waves across the Atlantic Ocean¹. As amateur radio enthusiasts got hold of radio sets in the 1920s they started working with wavelengths that were initially considered impractical for applications (much shorter than the hundreds of metres used by Marconi). These enthusiasts soon realised that they could communicate with other enthusiasts in distant countries through the reflection of the radio waves off of the (until then unknown) ionosphere¹. Gradually our understanding of radio waves and antennae design developed, leading to further, unexpected applications. Depending on the design of the antennae, radio waves (and microwaves, which have a slightly shorter wavelength of the order of 0.1-100cm*) could be made to be directional. So antennae could be made that transmitted waves only in set directions (or conversely could detect the direction from which radio/microwaves originated). This understanding of antennae design would lead to advances in Radar technology.

Which brings us back to the loop antenna at Coffee is my cup of tea. Loop antennae are grouped into two types, “small” and “large”. It is fair to say that it is a large window at Coffee is my cup of tea and so the loop antenna there would fit into the “large” category. These antenna are ‘resonant’ (meaning that they respond most) to wavelengths equal in length to the circumference of the antenna. From memory, I’d guess that the window was roughly 2m high and 3 m across, meaning it had a circumference of 10 m. We can calculate the frequency of the radio waves that would be resonant with this by using the fact that the frequency (f) is just the speed of light (c) divided by the wavelength (λ) (ie. f=c/λ). The speed of light is 3×10^8 m/s, so the frequency would be (3×10^8)/10 = 30 MHz. There are two last things to notice about this result. First, the name of Hertz lives on in the unit of frequency (Hz). Secondly, the loop antenna around the window at Coffee is my cup of tea is resonant with approximately the frequency of Citizens Band radio (CB radio operates at ~27 MHz). Which may make us question once more what this loop of wire is doing at this friendly little café on Dalston Lane.

Coffee is my cup of tea can be found at 103B Dalston Lane, E8 1NH

¹Britain’s shield radar and the defeat of the Luftwaffe, David Zimmerman, Amberley publishers (2001, 2010)

*Technically Hertz discovered microwaves rather than radio waves. However, given neither were named at the time and they are both of longer wavelength than visible light, it is perhaps too pedantic a point.

 

Categories
Coffee cup science Home experiments Observations

Aroma and batch brew

Isn’t it great to find a lovely, freshly brewed, hot cup of aromatic coffee in a quirky little café? Which bit do you enjoy most? That special aroma as you inhale the steam above your cup before sipping the coffee to compare the taste with the smell?

2-furfurylthiol
Representation of 2-furfurylthiol. Amazing what can be found (briefly) above your coffee cup.

As you may imagine, a fair bit of research has gone into working out which chemicals are responsible for that just brewed aroma (for a review see here). More than 800 volatile chemicals have been identified as key to the aroma of coffee of which the most important for that freshly roasted and brewed coffee smell seems to be 2-furfurylthiol. Although it has a complicated name, it’s got a fairly simple chemical representation (shown right). Responsible for the “roast-y, sulphur-y” smell in freshly brewed coffee the problem for us, and for 2-furfurylthiol, is that it is not very stable. In fact, in experiments in which a freshly brewed coffee was stored in a thermos flask to keep it warm, the concentration of 2-furfurylthiol in the space just above the coffee decreased by more than 50% within 20 minutes of storage. After an hour, the concentration of 2-furfurylthiol had decreased to less than a quarter of its original amount and shortly after that, it was gone completely (study can be found here). (Other volatile aromatics decreased similarly (here)).

So if you were to brew a coffee, put it in a flask to keep it warm and then drink it within 20 minutes, you will have lost more than half of the lovely coffee smell. And if, heaven forbid, you were to take it from its thermos 1hr after brewing, almost all those wonderful aromatics would have decayed away.

Lundenwic coffee
This was not a batch!
Could you taste the difference between freshly made drip brewed coffee and batch brew?

Why is this important? Well, it’s about batch brew. You may have noticed that batch brew is increasingly popular in many cafés. Offered as a way of getting a filter coffee ‘freshly’ prepared for you without the hassle of actually having to have the filter made there and then. Different establishments try to get around the inevitable aromatic loss by changing the batch every 30 minutes or storing it in a ‘low oxygen’ environment, but is this enough? Do we need some blind taste-tests on batch brew?

A problem is that the decay of 2-furfurylthiol is not just due to oxidisation. Sadly for us, its decay seems to be intimately tied to other qualities that we appreciate in the coffee, the melanoidins (that make the coffee brown) and other chemicals formed during the roasting process (the phenols and the quinones). So even in a low oxygen environment, that aromatic 2-furfurylthiol is going to react with the other chemicals that make coffee great to make batch brew less great.

weather, bubbles, coffee, coffee physics, weather prediction, meteorology
It’s all in the 2-furfurylthiol. That fantastic coffee aroma is due to a number of unstable aromatic compounds that rapidly decay after the coffee is brewed.

That’s the theory. Clearly many cafés have taste-tested the batch brew and found that it doesn’t make enough difference to be concerned about. And in practice there are many other factors that may make a batch brew better than a fresh drip coffee you can make at home (though it would be great if someone could point some of these out for me!), what we need is a citizen science type taste test. A blind test of the same bean, prepared as a fresh filter and a cup at the end of the storage life of the batch. They will most likely have different temperatures so this would need to be considered, either by pouring very little of each (so the fresh-filter cools quickly), or waiting for 5 minutes for your cup of fresh-filter to cool to the batch temperature. Do they taste the same? Do they smell the same?

So this is a call for some science experiments “in the field” (and seemingly for everyone to drink more coffee). If you enjoy a cup of “batch” and are a regular at a café, please do drop me a note to share your blind taste-test experiences. If you are a café, any tips you have as to how to store warm coffee for longer than 20 minutes without compromising the aroma would be very interesting to hear (though if you find a café storing batch for longer than approx. 30 minutes, I would seriously consider going somewhere else!). And if you just drink coffee at home, why not get involved too, prepare a filter coffee that you store in a thermos and another a bit later ‘fresh’, get someone to help you so that you taste them ‘blind’ and let me know what you think. The comments section below is always available, otherwise I can be found on Twitter and Facebook and will happily debate there.

Enjoy your coffee!

 

Categories
Coffee cup science Coffee review General Home experiments Tea

The idea of a coffee at A Wanted Man

“We cannot do without a view, and we put up with an illusion, when we cannot get at a truth“.

A wanted man, Chelsea, coffee cup
A wanted man becomes visible under thin coffee.

A Wanted Man on Chelsea’s Kings Road is unusual in many respects. Firstly, never before have I been to an espresso ‘canteen’, but then, neither have I had a coffee in a café that is part coffee-shop part waxing salon. While both wax based hair removal and coffee rely on bees, this is surely not the connection between these two enterprises. Nonetheless, once your coffee-loyalty card is full, you can choose: free brow shape, bikini wax or coffee. The coffee comes from Common Man Coffee Roasters in Singapore so it would be interesting to know how it was transported to Chelsea in order to retain its freshness, surely each batch is not flown in? On our first visit, we had a rich and smooth long black, a lovely aromatic banana bread and a good hot chocolate (with soy milk). There is plenty of seating in the front of the café and some more towards the back near the bar which was all fairly empty on our first visit but far more crowded (with singly-occupied tables) on my second visit (see below).

As I drank my coffee, hidden wording became visible at the bottom of the cup. “A wanted man” appeared beneath the coffee when the coffee was sufficiently thin. By tilting the cup, this “critical” thickness could be estimated, as you can see in the photos. Ah-ha I thought, the physics bit of this cafe-physics-review will be easy! The absorption of light (which we could measure by the visibility of the writing at the bottom of the cup) is directly proportional to the thickness of the absorbing liquid, the coffee. This is the Beer-Lambert law which describes how light is absorbed through substances such as coffee in which there are molecules and bits of sediment that absorb light (which is ultimately why coffee appears brown). Could I experimentally verify this bit of the Beer-Lambert law by somehow quantifying the visibility of the wording as a function of cup-tilt angle?

a tilted coffee cup at a wanted man
Absorption is a function of thickness and concentration

Before I had thought that far, I had finished the coffee, however the second part of the Beer-Lambert law could be tested by having another coffee on a separate occasion. The other part of the Beer-Lambert law states that the absorption (that’s the (in)visibility of the wording on the cup in this case) is also directly proportional to the concentration of the absorbing molecules/sediment. This makes sense, weak coffee is far more transparent than overly extracted coffee. On my second visit, the coffee tasted slightly stronger, a bit different from my memories of the first occasion. Did the “A wanted man” become visible at a different tilt angle? I would guess – or perhaps that should read ‘hypothes-ise’ – that the angle on the second occasion would have to be lower (that the coffee would have to be thinner generally).

However, while sipping my coffee (before getting to the tilt-angle-test) and looking around the second time I noticed that all along the wall where previously there had been plenty of empty tables, each one was now singly occupied by somebody using a laptop, a phone/tablet or in one case, both of these items together. This second time, my mind started wandering into more social issues, while looking at our screens and immersed in social media, are we able to see more or less, than our less absorbed fellow citizens? Does social media clarify the detail or cloud important aspects of our understanding?

Beer-Lambert applied to twitter and Facebook
Does social media do this to you? The light absorption of a coffee is determined by the thickness of the coffee and concentration of absorption sites within it.

After considering these two points, it became clear that in some ways they are connected. Admittedly a loose connection, and not one that is strictly scientific but perhaps it’s worth ‘running with it’ for a bit and seeing if it leads anywhere. Just as with the Beer-Lambert law with coffee, the more ‘interacting sites’ (or absorption sites) we encounter on social media, the harder it is to see through to the bottom. Twitter, Facebook etc. can be enormously helpful for widening our networks and learning about new things. But, as has been frequently pointed out elsewhere, they can also become quite unhelpful when we are in an “echo chamber” or when we think that points can be made in mere soundbites. Is it possible that the more absorbing and reflecting sites that we encounter, the harder it is to see anything to any greater depth? What we need is time-out, for self-reflection and for considering points made by others, on Twitter, Facebook and elsewhere.

Perhaps the best way to end such a post is with a long quote by somebody else. In fact, the same person (and in the same book) as was quoted at the beginning of this article. Perhaps it would be something to consider while we drink our coffees and hover over the ‘retweet’ or ‘share’ button. Are we helping to probe the depths of our cup by the links we share, or are we merely adding to absorption sites in soundbites in our networks?

“It requires a great deal of reading, or a wide range of information, to warrant us in putting forth our opinions on any serious subject; and without such learning the most original mind may be able indeed to dazzle, to amuse, to refute, to perplex, but not to come to any useful result or any trustworthy conclusion. There are indeed persons who profess a different view of the matter, and even act upon it. Every now and then you will find a person of vigorous or fertile mind, who relies upon his own resources, despises all former authors, and gives the world, with the utmost fearlessness, his views upon religion, or history, or any other popular subject. And his works may sell for a while; he may get a name in  his day; but this will be all. His readers are sure to find on the long run that his doctrines are mere theories, and not the expression of facts, that they are chaff instead of bread, and then his popularity drops as suddenly as it rose.“

John Henry Newman, The idea of a university.

A Wanted Man can be found at 330 Kings Road, London