Category: General

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Coffee cup science General Home experiments Observations Science history Tea

Is sixty the old forty?

Lundenwic coffee
What is the ideal temperature at which to serve coffee?

What is the optimum temperature at which to enjoy a cup of coffee?

A brief check online for the “ideal” serving temperature for coffee suggested a temperature of around 49-60ºC (120-140ºF, 313-333K) for flavour or 70-80ºC (158-176ºF, 343.1-353.1K) for a hot drink. In my own experiments (purely to write this article you understand), I found that I most enjoyed a lovely coffee from The Roasting House (prepared by V60) at around 52ºC. My old chemistry teacher must have been one who enjoyed the flavour of his coffee too. His advice for A-level practicals was that if we wanted to know what 60ºC ‘felt’ like, we should consider that it feels the same on the back of our hand as the underside of our cup of coffee. So, for argument’s sake, let’s say that we serve our coffee at the upper end of the flavour appreciation scale: 60ºC.

But, have you ever stopped to consider what 60ºC means or even, how we arrived at this particular temperature scale? Why do we measure temperature in the way that we do? While there are interesting stories behind the Fahrenheit scale, today’s post concerns the Celsius, or Centigrade, scale. Indeed, we use “degree Celsius” and “degree Centigrade” almost interchangeably to mean that temperature scale that has 0ºC as the melting point, and 100ºC as the boiling point, of water. It is one of those things that has become so habitual that setting 0ºC at the freezing end and 100ºC at the boiling end seems obvious, intuitive, natural.

thermometer in a nun mug
Careful how you drink your coffee if you repeat this experiment!

And yet the temperature scale that Anders Celsius (1701-1744) invented back in 1741 did not, initially, work this way at all¹. Celsius’s scale did indeed count from 0ºC to 100ºC and was defined using the same fixed points we use now. But rather than counting up from the melting point, Celsius’s scale counted up from 0ºC at the boiling point to 100ºC at the freezing point. Rather than degrees of warmth, Celsius’s scale counted degrees of cold. So, in the original Celsius scale, the serving temperature of coffee should be 40ºC: Sixty is indeed the old forty*.

Which immediately begs a question. Why is it that we count temperature up (the numbers get higher as it gets hotter)? A first answer could be that we view that temperature is a form of measurement of ‘heat’ and that heat is an energy. Consequently, something cold has less energy than something hot, “cold” is the absence of “heat” and therefore what we should measure is “heat”. This means that our thermometers need to indicate higher numbers as the temperature gets hotter, and so we are now counting the correct way. While this is good as far as it goes and certainly is our current understanding of ‘heat’, ‘cold’ and temperature, how is it that we have come to think of heat as energy and cold as the absence of heat? It was certainly not clear to scientists in the Renaissance period. Francis Bacon (1561-1626) considered that cold was a form of “contractive motion” while Pierre Gassendi (1592-1655) thought that although ‘caloric’ atoms were needed to explain heat, ‘frigoric’ atoms were also needed to explain cold.

effect of motivation on experience of pleasure while drinking coffee
How heat, rather than visible light, is reflected provides clues as to why we measure temperature ‘up’.

One experiment that helped to show that heat was an energy (and so lent support to the idea of measuring temperature ‘up’) was that of the reflection of heat by mirrors. In the experiment, two concave mirrors are placed facing each other, some distance apart. Each mirror has a focal length of, say, 15 cm. A hot object is placed at the focal length of the first mirror. At the focal point of the second mirror, is placed a thermometer. As soon as both objects are in place, the temperature indicated by the thermometer increases. If the mirror were covered or the thermometer moved away from the focal point, the temperature indicated decreases again to that of the room. It is an experiment which can easily be demonstrated in a lecture hall and which fitted with a view point that cold is the absence of heat.

However, around the same time as this initial demonstration, Marc-Auguste Pictet did another experiment, the (apparent) reflection of cold². The experiment was as before but in Pictet’s second experiment, a flask containing ice replaced the hot object. On repeating the experiment the temperature indicated by the thermometer decreased. Covering the mirror or moving the thermometer from the focal point of the mirror resulted in the indicated temperature increasing again. Just as ‘heat’ was reflected in the mirrors, so too (seemingly) was ‘cold’.

So, the question is, how do you know what you believe you know about heat? Are there experiments that you can design that could help to disprove a theory of ‘frigoric’? And how do you explain the experiments of Pictet? Reader, it’s over to you.

 

*Within ten years of Celsius’s death (of tuberculosis in 1744), his colleagues Martin Strömer and Daniel Ekström had inverted Celsius’s original temperature scale to the form we know today. A similar scale designed by Jean Pierre Christin was also in use by 1743³.

¹”Evolution of the Thermometer 1592-1743″, Henry Carrington Bolton, The Chemical Publishing Company, 1900

²”Inventing Temperature”, Hasok Chang, Oxford University Press, 2008

³”The science of measurement, a historical survey”, Herbert Arthur Klein, Dover Publications Inc. 1988

 

Categories
Coffee cup science General Home experiments Observations Tea

Making a splash

You spilled your coffee, a terrible accident or an opportunity to start noticing?

Why do some droplets splash  while others stay, well, drop like? It turns out that there is some surprising physics at play here. When a drop of water, or coffee, falls from a height and onto a flat surface (such as glass), we are accustomed to seeing the droplet fracture into a type of crown of smaller droplets that form a mess over the surface. Visually spectacular, these splashing droplets have even been made into an art form (here).

Fast frame-rate photography reveals how each micro-droplet breaks away from the splashing drop:

Video taken from Vimeo – “Drop impact on a solid surface”, a review by Josserand and Thoroddsen.

 

So it perhaps surprising to discover that there are many things about this process that we do not yet understand. Firstly, if you reduce the gas pressure that surrounds the drop as it falls, it does not make a splash. In the extreme, this means that if you were to spill your coffee in a vacuum, you would not see the crown-like splashing behaviour that we have come to expect of falling liquids. Rather than splash, a droplet falling in low pressure spreads out on impact as a flattening droplet. This counterintuitive result was first described in a 2005 study (here) that compared the effect on splashing of droplets with different viscosities (methanol, ethanol, 2-propanol) falling through different gasses.

cortado, Brunswick House, everyday physics, coffee cup science
Don’t spill it!
But would a latte splash more or less than a long black?

The authors of the study ruled out the effect of air entrapment surrounding the droplet as it falls as high speed photography had not indicated any air bubbles in the droplet just before impact. Instead they considered that whether a drop splashes on impact – or not – depended on the balance between the surface tension of the falling liquid and the stress on the drop created by the restraining pressure of the surrounding gas. Calculating these stresses led to a second surprising result. Whether a drop splashes on impact or not depends on its viscosity (as well as the gas pressure and the speed of impact). But the surprising bit is that the more viscous the liquid, the greater the splash.

From a common-sense perspective (that may or may not have any bearing on the reality of the situation), an extremely viscous liquid like honey should not splash as much as a less viscous liquid like coffee. This suggests that there is an upper-limit in viscosity to the relation predicted in the 2005 study. After all, although the authors did change the viscosity of the liquids, the range of viscosity they studied was not as great as the difference between coffee and honey. This sounds like a perfect experiment for some kitchen-top science and so if any reader can share the results of their experiments on the relative splashes formed by coffee and honey, I would love to hear of them.

 

Categories
General Home experiments Observations Science history slow Tea

Reflections on physics and coffee

BeanThinking started as a way of slowing down and appreciating connections, often between a coffee and the physics of the wider world but also in terms of what can be noticed in any café. Perhaps, for this first post of 2017, it’s worth spending five minutes looking at your coffee while you drink it to see what you notice. Here are a few coffee connections that occurred to me recently:

reflections, surface tension
Reflections on a coffee.

Parallel lines and surface reflection: The parallel lines on the ceiling of a café were reflected in a long black. Surface tension effects on the coffee meant that the reflections were curved and not at all parallel. A piece of dust on the surface of the coffee was revealed in the reflection by the curved reflections of the ceiling. Astronomers can use similar effects (where images of a star appear in a different location to that expected) to infer the presence of dark objects between distant stars and their telescope. This gravitational lensing can be used to detect quasars or clusters of galaxies.

 

 

 

layering of coffee long black
Layers of coffee

Layering of crema as the coffee is consumed: The coffee stain effect and this layering of the crema suggests a connection between a coffee cup and geology. It used to be my habit to take a mug of tea with me when I taught small groups of undergraduates. In the course of one of these tutorials, a student (who had been observing similar layering in my tea mug) said, “You drink your tea faster when it is cooler than when it is hot”. Full marks for observation, but not sure what it said about his attention during my tutorials! Similar observations though can help geologists estimate the age of different fossils.

 

interference patterns on coffee
Bubbles in coffee

Bubble reflections: An old one but the interference patterns caused by bubbles on the surface of the coffee are full of fascinating physics. The fact that the bubbles are at the side of the cup and seem to be grouped into clusters of bubbles may also be connected with surface tension effects (although there is a piece of weather lore that connects the position of the bubbles to the weather. If anyone ever does any experiments to investigate this particular lore, I’d love to hear about them).

 

 

Coffee, Van Gogh
Art in a coffee cup

Van Gogh’s Starry Night: The effects of vortices and turbulence caused the crema of a black coffee to swirl into patterns reminiscent of this famous painting by Van Gogh. As a result of posting this image on Twitter, @imthursty sent me a link to this preprint of a paper submitted to the arxiv: the connections between Van Gogh’s work and turbulence. A great piece of coffee combining with art and science.

 

So many connections can be made between tea, coffee and science and the wider world, I’d love to see the connections that other people make. So, if you see some interesting physics, science or connections in your coffee cup, why not email me, or contact me via FB or Twitter.

 

Categories
General Home experiments Observations Tea

An easy way to get a halo

The other day I was talking to a primary school child about condensation, what it was, where to see it etc. So I asked,

“Do you drink coffee?”

“No.”

“Do you drink tea?”

“No”

(I started to worry about the future generations). Nonetheless, I pulled out my cup of steaming coffee and pointed to the water droplets around the edge of the mug (which are very common if you haven’t warmed your cup before pouring your hot coffee into it) and noticed a sudden expression of recognition cross the child’s face.

“Like when you breathe on a mirror?”

Kettle drum at Amoret
Condensation on around the top of the jug on this V60

Yes, exactly so (and probably a much better example for a kid anyway, the problem of being an adult with a one track mind!). As the child had realised, the science in your coffee cup is connected to phenomena that occur elsewhere in the world. In the case of condensation, it occurs when the temperature of the surface onto which condensation happens is below what is called the “dew point”. Determined by the relative humidity in the environment, the dew point is the temperature below which water vapour in the air will condense into liquid water.

Of course the dew point gets its name from the dew that can form after a chilly night. Which brings us to another property of those water droplets that form around the rim of your coffee mug. Although it is not easy to see on the mug, each droplet is acting as a lens, focussing the light that falls onto it. As the surface of the mug is fairly flat, rather than form spherical droplets, the drops that form on the side of the mug are squashed hemispheres. This is not the case when dew forms on grass. Tiny hairs on the surface of the grass protrude from the leaf meaning that the water droplets form into spheres (which is, incidentally very similar to the reason that a duck is so waterproof). When the sun comes up, each sphere of water focusses the sunlight onto the grass behind it which reflects it back, right in the direction it came from.

heiligenschein, self portrait
Self-portrait with weak heiligenschein. Share your photos with me on FB or Twitter.

This means that if you stand with your back to the sun and look at your shadow on dew covered grass, you will very probably see a region of bright light surrounding your head, your heiligenschein. German for “Holy light”, heiligenschein is the effect of all of those spherical dew lenses reflecting the sunlight back towards you. You can only see the effect around your ‘anti-solar’ point (a position defined as being 180º from the Sun from the viewpoint of the observer, see here for what this means visually). This means that while you will see heilgenschein around your head, or around the shadow of the camera that you use to photograph it, you will never see the halo around someone else’s head even while they themselves can clearly see it.

I’m sure there’s some sort of metaphor there, perhaps one to contemplate next time you’re drinking a hot, steaming coffee.

 

Categories
Coffee review General Observations Science history slow

Science & Religion at Rag & Bone Coffee, Westminster

Rag&Bone, Rag & bone, coffee Victoria, coffee Westminster
Rag & Bone Coffee in front of St Matthew’s Church.

Can a coffee cart provide the time and space for reflection and enjoyment of a coffee just as a sit-down cafe can? In seeking an answer to this question (as well as on a quest to find more great coffee in the Victoria/Westminster area), I turned up at Rag & Bone coffee on Great Peter St. It was quiet when I arrived in the courtyard of St Matthew’s Church, and the barista took time to make me a lovely, fruity and full bodied Americano (with beans roasted by Old Spike Roastery). Obviously, there is no seating around the bar but, the church behind the cart is open everyday and offers a rare quiet spot in Victoria to sit and reflect, should you want to do so, before you buy your coffee of course! Sadly, as this is a cart and not a sit-down cafe, the cups provided are disposable, but there is nothing to stop you taking your keep-cup along in order to enjoy your coffee. Just behind the cart, a crucifix above the door of the church caught my eye. And that got me thinking about something, perhaps slightly tangential to the ordinary cafe-physics reviews of Bean Thinking, why do some people imagine there is a conflict between religion and science?

I could see how there could be a disagreement if a religion took an overly literal interpretation of a text (as can happen with disputes over evolution). Or if someone used science as an argument against ‘belief’ while failing to appreciate that science too is based on belief (albeit beliefs that we are most likely just to assume as facts without questioning: particularly that our world exists and that it can be understood). But outside those extremes, and if we look at the motivations of both religion and science, it is surely that both religion and science aim to discover or value truth. If both sincerely follow that aim there can be no real conflict, for truth cannot contradict itself.

Earth from space, South America, coffee
One planet. One home.
The Blue Marble, Credit, NASA: Image created by Reto Stockli with the help of Alan Nelson, under the leadership of Fritz Hasler

Instead the investigations of one can inform the other and help both to advance our understanding of the world. Take for example the urgent issue of climate change. Scientists, using science as a tool, can investigate and highlight areas of concern for our planet (increasing CO2 levels, rising sea temperatures, a probable increase in extreme weather events, etc) but strictly speaking, as a tool it can go no further. If a scientist then urges us to do something to mitigate climate change, they are not speaking as a ‘scientist’ but as a human being; a human being who is informed by ethical concerns. It would be perfectly logical for someone to recognise that climate change is happening while holding that there is no obligation on our current generation to do anything about it. We may find such an opinion objectionable but that is the crux of it, we have introduced values to the discussion in the form of ‘right and wrong’ and ‘good’. We have moved beyond the remit of science. Religions have had millennia to consider the human condition and what constitutes ‘good’ or ‘right’. For us to combat climate change we need not just the evidence that it is happening, but an idea of a better, or more ‘just’ world. Ethical systems are of course possible without religion, but discussion informed by religious concern can help to change ‘concern for our planet’ into the concern for and protection of ‘our common home‘.

Artemisworks photography, rosary and keyboard
Prayer beads on a keyboard.

Then there is a link between religion and science that brings us right back to Rag & Bone Coffee and St Matthew’s church yard. When St Matthew’s was built back in 1849, the area surrounding it was squalid, conditions were so bad, the area towards Victoria St. was known as the “Devil’s Acre“. The Dean of Westminster, and the new vicar of St Matthew’s recognised that, to help people out of poverty, drastic steps would need to be taken and one of these was to improve education. The Dean of Westminster died soon after St Matthew’s was built but his wife, Mary Buckland, who was also a palaeontologist, wanted to continue his work with the poor. In order to improve the conditions for those living in the slums in the Westminster area, “Mrs Buckland” established a coffee house on Old Pye St, that was cared for by the Revd. Richard Malone, vicar of St Matthew’s. The coffee house was a place where lectures were given and a library was set up. The church and people in the scientific world, worked together to help the poor of the area positively change their living conditions.

The coffee house eventually had to close but, perhaps it could be said that, in a sense, the presence of Rag & Bone coffee in the courtyard of St Matthew’s, continues this work. Although times have changed, and the area is no longer a slum, there is a different form of poverty, people who are time-poor and harassed, working in the offices that now surround the church. In this sense, Rag & Bone Coffee offers not just refreshment, but a brief time-out from the daily grind for the people who now pass by this space. As making coffee is both an art and a science, perhaps we can also say that here too, science and religion work together, with coffee, to make the world a better place.

Rag & Bone Coffee can be found in the courtyard of St Matthew’s Church, Great Peter St. SW1P 2BU.

 

Categories
Coffee review General Observations slow

2 years in

3D hot chocolate art on an iced chocolate, Mace, Mace KL, dogs in a chocolate
Happy birthday to me

Last weekend, Bean Thinking turned 2. So I’ve been looking back at the cafés I’ve visited over the past two years. Bean Thinking started as a way to slow down and to try to see things in a (slightly) different way, to really enjoy the coffee but also to take time to explore the stories, and the science, that can be found in different cafés. I’ve enjoyed the coffee in each café that I have visited but, as always happens, some stick in the memory a little more than others.

So I decided to pull together five cafés which, for me, had an interesting story to tell or prompted an unexpected chain of thoughts. I have sadly had to leave out some great cafés and some really fun stories (for me to think about at least). However, these five stood out. Each café introduced an unexpected bit of science to me, or had something about them that meant that slowing down and enjoying the coffee provided a really special moment. Consequently, each café features for slightly different reasons, and so rather than create a top 5 (which would be impossible anyway), I have listed them alphabetically. I hope you’ll excuse this trip down memory lane.

Amoret, Hammersmith

Kettle drum at Amoret
Coffee on a drum at Amoret

It is not every day that a well made V60 can transport you to another planet. Yet that is what happened for me at Amoret in Hammersmith. The cylindrical design of the table reminded me of a drum but the question is, why do drums make the sounds that they do? The answer to this question took me on a journey into sounds. Just how different would Bach’s famous fugue sound if played on Venus rather than Earth? And then a surreal moment as a Dutch TV station decided to take Bananarama to Venus courtesy of research conducted at Southampton University. This was all accompanied by great coffee in a very pleasant cafe, the review can be found here.

Coffee Affair, Queenstown Road,

Contemplating the floor at Coffee Affair
Contemplating the floor at Coffee Affair

Where better to slow down and appreciate the moment than a place reminiscent of the geology of the South Downs that helped Charles Darwin to argue the case for his theory of evolution. Coffee Affair occupies the old ticket office at Queenstown Road station. The fixings and the floor of the café reveal evidence of the people who inhabited this space in times past. Watching the V60 being prepared, slowly, carefully, exactly, emphasises this sense of time. The result is great coffee in a place that almost forces you to step out of the speed of modern life and stop, put down the smart phone and take time to just notice. Coffee Affair was reviewed here.

Lumberjack, Camberwell,

Lumberjack coffee Camberwell
Exploring local connections at Lumberjack

There’s a strong emphasis on keeping it local at Lumberjack in Camberwell, as well as a preoccupation with all things wooden (this being an enterprise set up with London Reclaimed). So it was interesting to discover that there was a fairly local connection between Camberwell and the ultimate ‘local’ London tree, the London Plane. Not only that, but research that had been published a few weeks before I went to review Lumberjack had shown that, surprisingly, the wind speed needed to fell a tree was fairly constant at around 56 m/s, irrespective of the size or type of tree. This surprising finding was the cherry on the cake for this ultimate in local reviews (here).

Red Door, Greenwich,

vortices, turbulence, coffee cup physics, coffee cup science
Beautiful physics at Red Door

Just what would happen if you put a cup of coffee on a record player? A turntable in a corner at Red Door in Greenwich meant that not only did I start to think about this question, I decided to start some experiments to find out. The resulting physics was physically as well as scientifically beautiful. The experiments can be done by anybody with equipment that you can probably find at home (though I would recommend not using an actual turntable). It turned out to be an elegant experiment involving vortices, but as Helmholtz noticed, similar vortices form in organ pipes, the atmosphere and even in electromagnetism. Truly a beautiful piece of connected physics that I would have missed had I enjoyed my coffee ‘takeaway’. More here.

The Turkish Deli, Borough Market,

Turkish coffee
The universe in a cup of coffee at The Turkish Deli

“The universe is in a glass of wine” so said a Greek poet according to Richard Feynman, but at the Turkish Deli it is more obvious in a cup of coffee. When made properly, Turkish coffee requires at least four minutes of ‘settling time’ before it can be enjoyed. You could use this time to think about how the concentration of coffee particles changes as a function of the depth. Similar considerations led Jean Perrin to conduct experiments back in 1910 that he declared showed that “… it becomes very difficult to deny the objective reality of molecules” (which before that point had indeed been very much denied). Now that The Turkish Deli also roast and grind their own coffee on-site, there is even more reason to visit and ponder the connectedness of our coffee and our planet. The Turkish Deli was reviewed here.

With so many more cafés to explore, and things to discover, who knows what the next year or two will bring. And if you’ve got a recommendation or found a great café where you have stopped and noticed something intriguing, no matter how lateral, why not drop me an e-mail, I’d love to hear your experiences of slowing down and appreciating our coffees.

 

Categories
Coffee cup science Coffee review General Observations Sustainability/environmental Tea

A cup of tea for a light bulb moment at Ginger and White, Hampstead

Coffee, Ginger and White, Hampstead
Coffee at Ginger and White, Hampstead

It was late afternoon by the time we stopped by Ginger and White in Hampstead. The warm weather meant that we could enjoy time spent sitting outdoors in the little alleyway in front of the café. We had been taking a friend around the various sights (and foodie places) of London and so stopped here before heading back home. The long black, cortado and soya latte were all very well done and, while the others had enjoyed a crepe at La Creperie de Hampstead just around the corner, I took the opportunity to try the excellent banana bread on offer at Ginger and White. There was a fairly good selection of cakes on offer, but sadly those that the staff could confidently affirm were nut free were far fewer. However, the moist and tasty banana bread was a good option anyway. Coffee was roasted by Square Mile and there were also Square Mile beans available for purchase should you wish to take some home with you. While the café was fairly busy, it was nevertheless a relaxing place to sit and watch the people of Hampstead go by.

The interior of Ginger and Whites
Everything is connected. From the lights to your cup of tea.

As I was looking around, wondering what the physics part of this cafe-physics review would be, I had what you could call a “light-bulb moment”. The walls of the building opposite were reflected in the windows of the café but looking inside, I noticed the lights which appeared to be LED lightbulbs set-back into the ceiling. Along with requiring less energy to power than conventional or halogen lightbulbs, LED lightbulbs in a café offer another, more poetic advantage for the café: they have a connection to the drinks being served and particularly tea. It’s all about diffusion.

At the heart of an LED light, there are two materials that form a junction. On one side of the junction is a semiconductor material that conducts electricity by means of electrons. Electrons conduct electricity in metals and are the ‘normal’ way that we consider electrical current to  be carried. On the other side of the junction is a different semiconductor, one that still conducts electricity but this time does so with carriers called ‘holes’. You can view the electrons as having a negative charge and the holes as having a positive charge.

tea bag, tea cup, diffusion, turbulence
What happens when you put a tea bag into a cup of cold water. How long until the water becomes ‘tea’?

But what happens at the junction? Is there really a sharp barrier between these two types of material? Think about putting a tea bag in a cup of cold water, does the tea bag just sit there or does it slowly, very slowly, start to diffuse tea into the cold water? It is a similar thing for the two materials. Slowly the electrons diffuse into the hole material and the holes into the electron material. In fact, mathematically, the same equations describe the process in the junction as in the tea cup. But unlike tea, in the LED, the holes and electrons have an electric charge associated with them and so, as they diffuse away from the junction, they set up an electric field across the junction. It is this electric field that eventually stops any further diffusion of electrons or holes across the junction and sets up the conditions necessary for LEDs to emit light. It would be like having a tea bag that diffuses tea into the cup until it is perfectly brewed and no further.

Of course, there is much more than this to understanding LEDs. If you’re interested, there is further information here. I find it fascinating however that what happens in your tea cup, is also happening on many different scales in many places in the universe. And of course, in the lighting of cafés and coffee houses around the world.

Ginger and Whites is at 4a-5a Perrins Court, NW3 1QS

 

Categories
General Observations slow Sustainability/environmental Tea

Environmentalism through V60s

Is there a parallel between trying to live more sustainably and the art, or science, of coffee appreciation?

San Sebastian via Aeropress
Enjoying a coffee prepared in an Aeropress at Alchemy

Consider the way that we experience our coffees. Who would not wish that more people took time to enjoy great coffees, perhaps single-origin pour-overs, precisely measured and lovingly made, obviously without milk. But we know from experience that not everyone is ready to take the risk of trying a new café and paying that bit extra for a coffee they do not know. Our own coffee journey may illustrate this point. My student days were filled with supermarket (cheapest brand) instant and machine coffee (20p between lectures). Slowly I graduated (quite literally, a well known chain opened close to the university in my final year) to grande lattes, flavoured with nutmeg and similar drinks. A smaller chain introduced me to macchiatos and black coffees before I found a start-up roasting company on the internet and suddenly my mornings were transformed with the fragrance of freshly roasted and freshly ground, aromatic and lovely coffee.

Each step I took introduced me to better, more interesting coffees. New coffee roasters opened offering different levels of roast and different types of bean. Great independent cafés started up which featured coffees brewed in new and innovative ways (the Aeropress was only invented in 2005). Social media and more traditional friend circles introduced me to people who really take time to savour their coffee and which in turn has enabled me to grow in my own coffee appreciation. Would I have jumped from instant to pour-over? Probably not. And yet, I know that I am still on a coffee-appreciation journey: There is still so much more to learn, so many new things to experience, it is a journey I’m very happy to have embarked upon.

kettle, V60, spout, pourover, v60 preparation
How much CO2 does over-filling your kettle really produce?

So what is the link with environmentalism or indeed science? Well, how many times have you heard that if only we filled the kettle just to the correct amount, we would save so many tonnes of carbon dioxide emissions annually? A counter argument points out that given how much pollution we are actually responsible for, merely correctly filling the kettle (or avoiding takeaway cups) is going to have negligible environmental benefit. It is here that I think that the analogy comes in.

It is true that, when you tot up your daily energy consumption, the use of a kettle is not a very big part of it*. For me, even when I overestimated my kettle use (and underestimated the energy costs involved in transporting the kettle/coffee etc. to my kitchen as this became difficult to estimate), my energy use coming from the kettle was only 2% of my daily average. If I only considered the energy consumption due to electricity per day, of course the contribution of the kettle would be higher but it is still not that big a deal.

Over-boiling the kettle does not seem to make that much of a difference when compared to the difference we will have to make in order to limit climate change. Which takes us to the very valid argument that “if everyone does a little, we’ll achieve only a little”†. But, is it worth being just a little bit more optimistic on this? Let’s bring in the coffee.

Earth from space, South America, coffee
One planet. One home.
The Blue Marble, Credit, NASA: Image created by Reto Stockli with the help of Alan Nelson, under the leadership of Fritz Hasler

It is all too easy to breeze through life not considering our environmental actions, I’d argue that this is the instant coffee stage. As we start to become more aware of the environment, we perform small actions (buying – and of course reusing – a keepcup, only filling the kettle just-so). That’s great, we’re drinking pumpkin-spice lattes. It may not be the best coffee we can get but we are enjoying it. Analogously, as we increase our environmental awareness (and subsequent responsibility) we seem to find that small things become more enjoyable, and even more rewarding. The effort involved in trying to improve our environmental behaviour brings benefits in terms of the amount we enjoy or the appreciation of the things that we have. The small step brought about by considering our kettle use, enables us to make the larger steps that are necessary to behave more environmentally. Trying to make big changes quickly may, in some ways be great (it would indeed be better if everyone appreciated single-origin pour-overs without milk), but it is unlikely to work. To my mind, even if people really started to appreciate good pumpkin-spice lattes that would be a step away from the horrors of instant and towards a better future!

But is an environmental pumpkin spice latte enough? Can I say that I now behave in a properly sustainable and environmental way? Sadly not. Exactly as with the coffee, I am far too aware that I’m on a sustainability journey: There is still so much more to learn, so many new things to experience, it is a journey I’m very happy to have embarked upon. Some do a lot better with the environmentalism, some are still drinking instant coffee, but small steps help us to make the large steps that are going to be needed. Back in the 1990s, as more people began drinking flavoured, grande lattes, so it became possible for the small independent cafes to open up and improve the coffees on offer. We need to move on from pumpkin spice environmentalism, let’s hope we make the steps soon enough.

*You can easily calculate your own energy use with the guidance in David MacKay’s excellent book “Sustainable Energy – without the hot air” that he made fully available online (click the link). In a series of easy steps and estimates that you can make, he helps you to calculate your average daily energy consumption (which can be translated, if you so wished, to a personal carbon dioxide emissions calculation). I would highly recommend going through and looking at your own consumption to see how big an effect, for you personally, over-filling the kettle is.

† Quote from “Sustainable Energy – without the hot air” by David MacKay, UIT Cambridge Ltd, 2009

Categories
Coffee review General Observations slow Sustainability/environmental Tea

Environmentalism inside and out at Farmstand, Covent Garden

Farmstand Drury Lane
Farmstand on Drury Lane

How can we live sustainably, buying locally, being mindful of our ecological footprint and still drink coffee? A recent trip to Farmstand on Drury Lane revealed a café conscious of its environmental responsibilities, somewhere that is trying to help us to make a difference while still enjoying good food and great coffee. Is it possible for us to have our coffee and drink it? The people behind Farmstand certainly seem to think so.

The bare brick walls inside the spacious Farmstand have a certain rustic charm that serves to emphasise the environmental concerns of the café. A focus on local, free range meat and GM free vegetables means that this is definitely a place to be considered when looking for a lunch spot (though on this occasion, we only tried the coffee). Coffee is obviously not locally grown but is roasted by Workshop which is, relatively speaking, just down the road. Tea meanwhile comes from Postcard teas, just up the street. Water is complementary and is provided on tap so as to reduce plastic waste. The service was friendly and with such a bright and airy feel it is a very pleasant space to enjoy an Americano (though I imagine it is fairly crowded at lunchtimes). However, the Americano was served in a take-away cup (when I specified I was staying in). After a bit of digging on their website, I discovered that they use compostable and/or recyclable packaging sourced from London Bio Packaging. However, as it is not easy to either recycle nor to compost cups in regular waste collection (including recycling collections), it would be interesting to know details of how they dispose of their cups so as to know how they reconcile this with the otherwise careful environmental policy.

Interior vertical gardening
Green wall inside Farmstand

As you enter the café, there is a staircase on the left hand side. Potted plants are fixed to the railings making what seems to be almost a miniature green wall. A great way to get houseplants into a small space, this seemed a small scale example of the green walls that are starting to pop up around our cities. Green walls are vertical gardens. They can be grown either with climbing plants or with a second structure on the wall that supports the hundreds of plants. Along with an aesthetic appeal (certainly true of the structure at Farmstand), these green walls have environmental benefits too.

A big environmental problem in cities is particulate pollution from exhausts. Specifically, particulate matter that is less than 10 μm diameter (think Turkish coffee grind) can irritate the lungs and cause health problems for the city’s inhabitants. Particulates less than 2.5 μm diameter are even more dangerous to health. Worldwide, in 2012, 3.7 million early deaths were associated with poor air quality. In London, a 2010 study showed that approximately 4000 deaths per year were the result of exhaust fumes. Which brings us to the first reason that green walls in cities may be such a good thing: Plants adsorb the pollutants.

Green wall Singapore
A green wall at the Ocean Financial Centre in Singapore, Image shared under cc license (attrib. share alike) by smuconlaw.

Over a three month period, a study by Imperial College showed that a single green wall on Edgware Road tube station had removed 515 g of particulate matter from the atmosphere. Using a mix of plants on the wall was found to increase the air turbulence around the wall and so increase the adsorption of the pollutants. Of course, different plants performed differently (in terms of their ability to remove particulate matter from the air). One of the plants on the wall (Convolvulus cneorum) could take out up to 2.73±0.16 g/m² of particulate matter*. On the other hand, another plant on the wall (Hedera helix) took out much less, removing only 0.28±0.02 g/m². However, we know Hedera helix by another name: Ivy. And ivy plants can produce a lot of foliage per plant very quickly. Convolvulus cneorum on the other hand, is a small plant with small leaves. While its efficiency could be very high, the amount of pollution it can remove may not be as great as an ivy plant, purely as a consequence of its leaf size.

Which brings us to questions of aesthetics and practicality. The wall at Edgware Road is planted with many different types of plant in order to produce an effect that reduces pollution while also being good to look at. Similar walls have sprouted up all over the world. However, for short term projects that require a large amount of foliage quickly, planting ivy can be a good option as a pollutant remover. Some of the temporary structures built along Park Lane for the Crossrail project are now covered with ivy. Although I had initially thought that this was due to a lack of weeding, it turns out that this is part of a step towards pollution reduction in our cities (modelling data has indicated that these green walls can reduce the local particulate pollution by 10-20% depending on the geometry of the wall and the plant species growing).

A small step perhaps, but one that is definitely in the right direction. The green wall at Farmstand could therefore be said to illustrate the idea that if we are to make a difference to our external world, we must start by reforming our own interior one. We need to make green walls not green wash and we can start by paying attention to what we plant inside and out.

Farmstand is at 42 Drury Lane, WC2B 5AJ

*The study looked at particulate matter between 2.5 µm and 10µm diameter (i.e. PM(2.5)-PM(10)).

 

 

Categories
General slow

Coffee contemplation

latte art, hot chocolate art, soya art
How can we learn to love our coffee more?

While writing last week’s cafe-review (about our sense of smell), I started to think about how to taste and appreciate coffee better. I don’t know about you but while I always try to take time to enjoy the coffee, ordinarily I don’t actively concentrate on the aroma and the sensation as I drink. This has the consequence that although I prefer some coffees over others, I am at a bit of a loss as to explain why. Moreover, it has knock on effects for how I buy my coffee.  Although I tend to look for coffees with tasting notes that say “chocolate” or “caramel”, from that point on it is a somewhat random mix of information about the coffee farmers, information about the farms, price, processing method etc. Sometimes this results in a great coffee arriving in the post a short while later. Sometimes one that, although good, is not quite my cup of tea. So how can I improve my tasting skills and so have more confidence in buying coffee. And a second question, should I?

There are some coffee roasters and suppliers who take this dilemma out of your hands. If you sign up with them, they ask you to merely click to say whether or not you like the coffee after you have tried it. After a few coffees, specially designed algorithms will start to identify which coffees you are likely to like and which you are likely to find more difficult.

Similar algorithms are being used by very different companies to suggest which videos we watch, books we read or adverts we see. It has been argued that the algorithms can know us better than we do ourselves, and that choosing our reading material, or coffee, through these algorithms will result in us enjoying what we read, and what we drink, far more than if we had allowed ourselves to choose more freely.

vending machine sign, scientism, reductionism
The sign on a vending machine. How valid is the reductionism that equates human beings with computers? Our ideas as algorithms?

But is this what we want? For a start, though I may like a coffee a great deal, to call it a ‘good’ coffee may be more tricky. But secondly, an algorithm will recommend products based on what we have enjoyed in the past. Often, in order to grow (as coffee drinkers or even as people), we need to be challenged, to read or to drink things that we may not necessarily enjoy but which we can learn from. There is one author in particular who I found not because I read work that was similar to hers but because one day I decided to browse the bookshelf starting at “A”. Perhaps what you could call a semi-random discovery. Similarly, I cannot in all honesty use the word ‘enjoy’ to describe one of the most memorable coffees I’ve experienced*. Nonetheless it had such a strange and remarkable taste profile that it challenged the way that I think about coffee and I am very glad that I purchased 250g of it!

So I suspect that I will not be signing up for an algorithm based coffee for now, but rather trying to understand more about how to taste and experience coffee through the tasting wheel for example. What about you? Do you want to be challenged by the occasional cup or do you think that the algorithms can help you to better understand your own coffee preferences? And, of course, if you have any advice on how to improve my coffee tasting skills, feel free to share.

 

*The coffee was a 2009 Indonesian “Sidikalang” from Has bean. More details in the cafe-revew for Lundenwic which can be found here.