coffee Covent Garden

Which direction? At Jacob the Angel, Neal’s Yard

Jacob the Angel, coffee Covent Garden
It is easy to miss Jacob the Angel as you enter Neal’s Yard, but an angel above the hoarding gives it away.

Jacob the Angel is tucked into Neal’s Yard in London’s Covent Garden. Named after Thomas Neale (1641-1699), Neal’s Yard is part of his development which is now known as Seven Dials. And rather like the larger 17th century development, this cafe-physics review of Jacob the Angel has a similar dilemma: so many avenues to explore, each wrestling for attention, which one to pursue?

But first the coffee. Roasted by Square Mile, coffee is available as the usual espresso based drinks or on V60 pour over. I had a Rwandan V60 that was full bodied and full of treacle like flavours. Owing to the geometry of the cafe, I didn’t get to check my ‘flavour notes’ against what the tasting notes thought I should perceive. The cafe space itself is fairly small but with a surprising amount of seating. Given this, it can feel a bit close as you squeeze past some of the people sitting down in order to place your order, (hence not double checking the tasting notes) however that is quickly set aside as you can gaze at the large selection of cakes (all with allergens clearly marked) arrayed on the counter.

On the walls of the cafe were paragraphs about the history of coffee and how a man named Jacob opened Britain’s first Coffee House in 1651 at the Angel Inn (in Oxford). The coffee itself came presented in a manner that was reminiscent of solar eclipses, while the sink next to our table was strikingly similar to those in my A-level chemistry lab. Unable to dissociate my memories of the sink with the reality of the environment at Jacob the Angel, it was a bit shocking when someone came to fill their glass of tap water there – don’t they realise what could have been in that sink?! Each thought train surfacing as a potential direction for the review, but then, above me, something moved. Looking up it was clear that a plant that was hooked to the ceiling was moving in a draught, but where was the breeze coming from? A small air-conditioning/heater unit was on the other side of the coffee house, circulating the air that was moving the plants.

plants, Jacob the Angel, Coffee Covent Garden
Plants above the tables at Jacob the Angel. How do they move in the breeze?

The moving plant had appeared to my peripheral vision as if it was floating in the breeze or perhaps flying. Now clearly there cannot be a flying plant, but in some ways the swaying leaves do illustrate the fluidity of air, which is a necessity for flight. The moving air demonstrates how the air imparts a force to the leaves (and the pot) causing them to sway. For things that genuinely fly this would be experienced as ‘drag’ – something that we have probably all experienced, even when not flying. Drag is increased if the object moving through the fluid (air) has a larger surface area perpendicular to the direction of movement: all being equal, bigger objects experience more drag. Imagine moving a spoon through coffee, it is easier to move a stirring stick rather than a tablespoon. But then, drag also depends in a non-trivial way on the shape of the object and how that changes the vortex wake behind it (look again at the spoon and how the vortices form behind it as it is dragged through coffee, you do not see those so easily with a stirring stick).

It is partly this sort of shape effect that seems to be behind Orsted’s recent restatement of the calculation of the amount of energy that their off shore wind farms can generate. By actually going out and measuring the air flow around the off shore wind farms, Orsted discovered that the air flow (which would be used to generate power) is affected not just by the individual windmill (as had been known and calculated), but its neighbours and the way these combine into the shape of the wind farm. There is still a lot we don’t understand about exactly how spoons move through coffee.

vortices in coffee
Vortices behind a spoon dragged through coffee.

But there is also a connection to a different type of “flying machine” if only through the name of the coffee house. For it was from the Angel Inn in (what is now) Aldwych that, more than 250 years ago, that an unusual ‘flight’ took place*. It was described in an advertisement in the paper:

“On Monday, the 5th of April 1762, will set out from the Angel Inn behind St Clements Church in the Strand…. a neat flying machine, carrying four passengers, on steel springs and sets out at four o’clock in the morning, and goes to Salisbury the same evening, and returns from Salisbury the next morning at the same hour… Each passenger to pay 23 shillings for their fare, and to be allowed 14lb weight baggage”.

How many more avenues could be followed while enjoying a slow coffee at this small but fascinating little cafe? Do let me know what you ‘see’ next time you visit.

Jacob the Angel is in Neal’s Yard, Seven Dials, London.

*”London Coffee Houses” by Bryant Lillywhite, pub. 1963

Spinning a yarn at E&J’s Pantry, Endell St.

E&J's Pantry on Endell St

E&J’s Pantry on Endell St

There are still a few areas of central London which seem a little short on good cafés. One such area lies just east of Covent Garden. So it was very fortunate that, on arranging to meet a friend nearby, I came across E&J’s Pantry on Endell St. The coffee is from Nude roastery and the interior, while not exactly spacious is large enough that we were able to sit undisturbed for quite some time. Along with good coffee, they serve lovely cakes which (according to their website) are made in their own kitchen. This is presumably why they could tell me confidently which cakes were nut free. (Those who follow @thinking_bean on Twitter may know that this is a bit of a hot topic for me.) I enjoyed a very good Long Black and a cake, before sitting back and taking in the surroundings.

On one of the walls inside E&J’s Pantry are a series of photographs. Each photograph is suspended by a thin thread from a rail near the ceiling. The observation reminded me of spiders webs and the (often heard) claim that spider silk is a natural material that is “stronger than steel”.

photographs, spiders web, nylon

Photographs inside E&J’s pantry. Can you see the thin threads holding up the pictures?

Unfortunately, the claim that “spider silk” is stronger than steel is a little disingenuous. For a start, there are many forms of spider silk. A ‘typical’ orb spider for example, will combine at least four types of silk to make a web. Secondly, even for the main type of structural silk (Major ampullate), the statement that it is stronger than steel is sadly pushing it a bit. The issue is that it depends on exactly how you define ‘stronger’ and the species of spider that makes the silk. Spider silk can be comparable to steel in terms of its tensile stress (how much it takes to break it), but it is when it is compared to steel based additionally on the weight of the material that spider silk can be considered ‘stronger‘. When you combine this with the fact that spider silk is more environmentally friendly (and biodegradable) than man-made comparable fibres such as Kevlar, it is clear why research is being done into understanding, and synthesising, spider silk.

A question arises. If it is so strong and so lightweight, why don’t we farm the spiders to harvest the silk? Wouldn’t this be quicker than trying to synthesise it? Clearly we weren’t the first to think this and a farmer in North Carolina, USA, tried in the 1930s. Unsurprisingly, there were issues. Firstly, it took 57000 spiders to produce 0.45 Kg (1 lb) of spider silk. Secondly, if they weren’t kept in (expensive) solitary confinement, they ate each other. It seems that the N. Carolina spider farm was not a commercial success. However, as described in the New Yorker (8th Feb, 1941), a certain Miss Mary Pfeifer did harvest spider silk in the first half of the twentieth century, for use as cross hairs in targets for surveyors and, more sinisterly, bombers. Glass engraving at the time was not fine enough for making the cross hairs. The thinnest line that could be made by a diamond cutter into glass was about double the diameter of the silk from spiders webs and so spider silk had an obvious ‘niche’ market.

HM Ng, spider on web

It takes several types of silk to spin a web. Image © HM Ng

In 1941, Pfeifer would pay “small boys” from the neighbourhood 15 cents for each useable spider that they caught and brought to her. She would then harvest the silk and wind it onto spools ready for use in target sights. Since then we have developed nanofabrication techniques which mean that very thin strands of metal (such as platinum) can be positioned onto the lenses. Continuous strips of metal of around 10 nm thickness (this is one thousandth of the width of a spider silk) can be routinely deposited. Through the development of these and similar manufacturing techniques we no longer need spider silk for use in cross hairs. It is probable that the market cornered by Mary Pfeifer no longer exists.

Spider silk however remains one of many areas where, by studying nature we get clues as to how to overcome various technological challenges. Sometimes devices possibilities are obvious, such as with the opportunity of synthesising material with the strength to mass ratio of spider silk. Sometimes however devices are a long way off. It would be a shame if we prioritised research into devices at the expense of appreciating the ingenuity of nature’s own solutions to its problems. As the story of Mary Pfeifer shows, sometimes today’s obvious devices are not those of tomorrow, who knows where research done purely out of curiosity would lead us.

 

E&J’s Pantry is at 61 Endell Street, WC2H 9AJ

More information about spiders webs can be found in “Spider Silk”, L Brunetta and CL Craig, Yale University Press, 2010

 

Rain drops at Notes, Covent Garden

Notes Covent Garden, rain, puddles

No one wanted to sit outside when we visited Notes at Covent Garden

It was a cold and wet afternoon in early January when I finally had the opportunity to try Notes (Covent Garden branch). Inside, there were plenty of places to sit while warming up and drying off enjoying a coffee. Although it seems small from the outside, inside, the branch feels quite open, with the bar immediately in front of you as you come through the door. One of the attractions of Notes to me, was the fact that I knew that they served different single estate brewed coffees. I think I tried a “La Benedicion” coffee, or at least that is what I seem to have scribbled in my notepad. We took a stool-seat at the window to look out at the rain as my coffee arrived in a 0.25L glass jar. It is always nice to try different single estate coffees and generally, if I know that a café serves single estate coffees I will seek them out to try them for the Daily Grind.

The reflection of the Notes sign board in a cup of tea

The reflections in a cup of tea

Watching the rain form puddles outside, my thoughts were turned to the reflections bouncing off the water in the puddle. It struck me that the appearance of puddles depends on the water molecules behaving both as individual molecules and as molecules within a group. The rain creates ripples in the puddle which can only occur because each molecule is (weakly) attracted to the other water molecules in the puddle, forming a surface tension effect. A ripple is a necessarily collective ‘action’. On the other hand, the reflection of the lights from the street is the response of each individual water molecule to the incoming light. The reflected image is made from the response of many individual molecules. Reflection is more of an individual molecule thing.

Warning sign, train, turbulence

Such turbulence should be familiar to anyone who has stirred a cup of coffee.

I continued thinking about this when I got home where it occurred to me that there was another connection between rain and coffee. It is often said that “rain helps clear the air”, or something similar. Yet this is not quite true. If you have a coffee in front of you at this instant, take a moment to drag a spoon through it. Note the vortices that form behind the spoon. Such vortices form around any object moving through a fluid. In the case of the coffee it is the spoon through the water. For the rain, as the rain drop falls through the air it creates tiny vortices of air behind it. Just as with the coffee spoon, the size of these vortices depend on the speed and size of the falling drop. These vortices pull and trap the atmospheric dust bringing it down to earth more quickly than rain alone could do. The air is cleaned more by this ‘vacuum cleaner’ action than by the ‘wet mop’ of the rain itself.

I’m sure that there are many other coffee-rain connections that you can make if you sit in a café as I did on a rainy day. Let me know your thoughts on this or indeed, on anything that you notice and think interesting while sitting in a café. There is so much to notice if we just put down the phone or close the laptop while enjoying our brew.

Edited to add: Sadly, this article was posted just as Notes Covent Garden was closing down. Notes still has branches at Trafalgar Square and in Moorgate and is opening new branches in Kings Cross and Canary Wharf in February I believe. Hopefully they will all serve single estate brewed coffee and have good window seats from which to observe the rain when it falls.