Month: September 2016

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.

 

Categories
Coffee review General Observations

A sense of history at Lundenwic, Aldwych

Lundenwic Aldwych coffee
The bar at Lundenwic

Of all the senses, our sense of smell is probably the one that is most likely to evoke memories that can take us right back to our childhood. One whiff of something as we walk past a café can, almost magically, transport us back many years and to a quite different time and place. This aspect of our sense of smell was brought home to me a few weeks ago on a visit to Lundenwic in Aldwych.

Lundenwic was the Anglo-Saxon name for the settlement that was located between what is now Covent Garden and Aldwych. As time progressed and the population of Lundenwic decreased, the site became known as the old-settlement (Aldwic), from which we get the name Aldwych*. Lundenwic is also the name of a (relatively) new cafe that has opened up near the corner of Aldwych with Drury Lane (incidentally, originally called the Via de Aldwych*). The upstairs seating area is quite small but with Caffeine magazines on hand, and plants dotted around, as well as the bar, there is plenty to watch and to notice while savouring your coffee. The espresso based coffee is sourced from Workshop while the filter option (V60 based) features different guest beans. On the day of our visit there were two filter options available. Opting for the Kenya Kagoumoini AA, I waited for my coffee to be prepared while my cafe-physics review companion had a late lunch of a cheese and ham toasty which quickly filled this small café with the aroma of cooking cheese. The tasting notes for the coffee stated that I should expect “rhubarb and raspberry lemonade”, and while the taste was certainly of lemonade, the aroma seemed to me quite different, almost spicy.

Lundenwic coffee
Kenyan coffee, freshly brewed appealed to all five senses, but each in different ways.

The cooking cheese and the memories evoked by the smells, along with this difference between the smell and the taste of the coffee, suggested that smell ought to be the subject of this cafe-physics review. Indeed, smell turns out to be a very interesting sense. The nerve cells relating to smell are the only type of nerve cell that can regenerate†. It is this ability of these nerve cells to regenerate that recently helped a previously paralysed man to walk again. Nerve cells from his nose were transplanted into his spinal cord where they helped in the regeneration of his spinal cord (for reasons that are not yet fully understood).

But what about those smells in the coffee? That special aroma, that you breathe in and appreciate immediately after you have brewed your cup is due to a fantastic mix of over 1000 volatile aroma chemicals. If you let your coffee stand, those chemicals evaporate off, which means that the just-brewed aroma starts to change. One of the most important chemicals for this coffee aroma is called 2-furfurylthiol. It has been shown that the concentration of 2-furfurylthiol in the coffee decreases by a factor of 4 over the course of an hour‡.  Even after as little as twenty minutes or so, the concentration of these complex aroma molecules starts to decrease significantly and so if you, (horror of horrors), were to let your coffee cool overnight and then zap it in the microwave in the morning, you would no longer regain that freshly-brewed smell that may have attracted you to the coffee in the first place.

durian skins and seeds
What was left after a session eating durian on a durian farm in Penang, Malaysia

This may also be the reason that the coffee at Lundenwic tasted differently to how it smelled. By inhaling the aroma and then tasting the coffee without exhaling (and so pushing the aroma back through the nose), our nerves are sensitive to different sensations. Although we may experience this while tasting many foods, occasionally it is crucial. A few years ago, Hasbean coffee were selling a very unusual coffee. The coffee, from Indonesia was called “Sidikalang”. Looking back at Hasbean’s “Inmymug” video, it is clear that it was very difficult for Hasbean’s Stephen Leighton to come up with tasting notes for the coffee which, in the end was compared with “durian”. The aroma of durian has been described as “turpentine and onions garnished with a gym sock” and yet in South East Asia it is known as the King of Fruits and is highly sought after for its taste. The aroma chemicals found in durian have recently been analysed (by the same group as studied the aroma of coffee). Nonetheless, the inclusion of “durian” in the tasting notes was extremely accurate (and did result in an amusing, if unconventional, attempt at opening one of the fruits in the video). It was accurate not only in terms of the experience of the taste/smell combination of that coffee. The actual taste and smell of the coffee was very similar to that of durian. A very unusual and interesting coffee that I have never yet had the opportunity to experience again.

However, to return to Lundenwic, how do the (lovely and inviting) smells that emanate from that café compare with the smells of the area that had been Aldwych before 1905 (when Aldwych was built, demolishing the slums that had existed there)? Some museums, such as the Canterbury Tales (in Canterbury), use the aromas (odours?) of medieval life to give visitors some idea as to what life was like in years gone by. Recalling a childhood visit to that museum, I would suggest that the smell of freshly brewed coffee and melting cheese is an almost unquantifiable improvement.

Truly we could say that at Lundenwic, it is time to wake up and smell the coffee.

Lundenwic is at 45 Aldwych, WC2B 4DR

*The London Encyclopaedia, 3rd Ed, MacMillan publishers, 2008.

†”On Food and Cooking: The science and lore of the kitchen”, Harold McGee, George Allen & Unwin publishers, 1988.

‡The coffee had been held at 80C in a thermos flask for the duration of the experiment. It may be expected that as your coffee cooled down, the volatile aroma molecules would evaporate more slowly than the time indicated in this study.

 

 

 

Categories
Coffee cup science General Home experiments Observations

Coffee, chaos and computing

Have you ever noticed drops of coffee skipping across the surface of your coffee as you have been preparing a V60? Or watched as globules of tea dance on the resonating surface of a take-away dragged across a table top? The dancing drops can be seen in this video of coffee being prepared in a V60:

These droplets are the result of some fascinating physics. Although we have encountered them on the Daily Grind before (here and here), the more physicists study them, the more surprises they throw up. While the droplets can be considered particles, they are guided around the coffee pot by the surface waves they create as they bounce. In a sense they are a macroscopic example of wave-particle coexistence. There is a significant temptation to explore whether they have relevance for the concept in quantum physics of wave-particle duality. But another aspect of this wave-particle coexistence has recently been shown to produce a different and unexpected connection. A connection between chaos and computing. And as you can create these droplets in coffee, perhaps we could say a connection between coffee, chaos and computing.

floating, bouncing drops
Drops of water can be stable on the water’s surface for much longer than 1 minute if you put the water on a loudspeaker, more info on how to create these at home here.

It is fairly simple to create these surface droplets in coffee at home. The secret to getting stable droplets on the surface is to create a vibration, a wave, on the surface of the coffee liquid. The droplets that then form on (or are introduced to) the surface ‘bounce’ on this wave. If you wanted to create surface droplets reliably at home, you would put your coffee on a loud speaker. I suspect that the reason that they appear in a V60 is that the first drops set up a standing wave on the surface of the coffee that acts to support later drops as they encounter the surface. If anyone has a different theory, please do let me know.

But how is it possible that these bouncing droplets connect chaos theory and computing? It is a consequence of the way that the globules of coffee on the surface interact with the waves that guide them around the coffee. Consider for one moment a particle bouncing around a confined space (the traditional example is of a ball on a billiards table). On an ordinary table, the billiard ball will behave quite predictably, start it off aimed roughly at the side of the table and it will bounce in an easily describable way. But if you make the ends curved or put circular objects in the middle of the table for the ball to bounce off, small differences in initial direction can result in large differences in the final path of the ball (for more details and an animation see here). The billiard ball behaves chaotically, and the initial path cannot be found from the final position, there is no way to re-trace the path of the ball, it is not “time-reversible”.

science in a V60
A still from the video above showing three drops of coffee on the surface.

The droplet bouncing on the liquid surface appears to move chaotically, just as the billiard ball on a circular table. However, unlike the billiard ball, the droplet is not a mere particle, but a particle linked to a self-generated surface wave. Each time the droplet bounces on the surface, it creates a small wave, like ripples on a pond. The path taken by the droplet is a complex interaction between this self-generated wave, the vibration keeping the droplet bouncing and the droplet itself. This means that if you are able to shift the phase of the bounce by 180º (meaning, that rather than bounce on an upward motion of the surface, the drop bounces on a downward motion or vice versa), the bouncing droplet not only reverses the direction it travels in, it retraces its path. Rather than behave as the chaotic billiard ball, the path taken by the seemingly chaotic globule of coffee can be exactly reversed.

Which is where the link with computing comes in. It is as if each “bounce” of the droplet “writes” information on the surface of the coffee in the form of a wave. The subsequent bounces “read” the information while the reversal of the direction of the bouncing droplet “erases” the stored information by creating a surface wave opposite to the initial one. The authors of the recent paper suggest that “in that sense [the walking droplet can] be termed as a wave Turing machine”, giving the final link to computing.

Whether or not this turns out to be useful for computing is, to me, almost irrelevant. What is interesting is that such a simple phenomenon, that anyone who makes pour-over coffee should have seen fairly often, is linked to such complex, and fundamental physics. If you would like to read more, there is a great summary article here while the actual paper is here.