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Allergy friendly cafe with good nut knowledge Coffee review Observations Science history Sustainability/environmental

Creating movement at Kahaila, Brick Lane

coffee Brick Lane, against trafficking, women's project, charity
Kahaila on Brick Lane. A small shop front concealing a large interior.

It’s always great to find an independent café selling good coffee (and cake) while giving something back to the community. It’s a reason to seek out small businesses rather than chains. Kahaila café on Brick Lane absolutely falls into this category. Although I had visited Kahaila previously, on that occasion the beigels (almost) next door were ‘calling’ and I did not give this space the time it deserved. This time however, the beigel shop had come first allowing us plenty of time to sit and ponder in this spacious café.

I had an espresso (toffee notes) together with a raspberry topped vegan chocolate cake (confidently nut free). There were a large variety of alternative cakes on offer at the counter along with cold drinks should you want them in summer. The espresso was a very enjoyable accompaniment to the cake (or should the cake be an accompaniment to the coffee?). The large room at the back of the café offered plenty of seating and was well lit by sunlight streaming through a window built into the roof.

coffee cake, Kahaila, Brick Lane
Raspberry vegan chocolate cake with espresso. The blue cup can affect the way the coffee is experienced.

One thing that immediately makes this café different from many others, is the fact that there is a donation box on the wall. Information cards on the table tops explain that Kahaila works as a charity providing education and support to women prisoners, helping women who have experienced abuse or are vulnerable in other ways to learn skills in a bakery and also offering a safe house for women who have been victim to exploitation and trafficking. All in all a café in which it would be good to spend more time (if only it were closer!). And assuming that the cakes are from the bakery, it forms a giving-circle with some great bakes on offer.

The vegan chocolate cake was a case in point. Beautifully presented, balanced in taste, in a perfectly sized portion to enjoy with a coffee. Ordinarily cakes require butter and eggs, how did the bakers manage it? Of course, a recipe was not given at the counter, nor would it necessarily have been particularly helpful to answer the question. Because the answer, if one exists, is a mix of their experimentation with flavours and textures together with an advancing knowledge of what each cake ingredient does.

sugar in a jar, Kahaila
The way these sugar cubes stacked in the jar and the sugar granules at the bottom reminded me of something. I was not able to put my finger on what it was…

Consider the egg yolk. In addition to adding mouth feel and texture to the cake or biscuit, the yolk contains emulsifying agents, such as lecithin, which act to stabilise suspensions of oil in water¹. With a hydrophobic section at one end of the molecule and a hydrophilic section elsewhere, the presence of lecithin molecules in the mixture prevents droplets of oil from grouping together and coalescing so as to separate into oil/water layers. By experimenting with non-egg based lecithin, a baker can combine different flavours and textures to produce a vegan cake.

A few years ago, a somewhat similar problem was vexing materials scientists: how to remove toxic lead from piezoelectric devices. Piezoelectric devices expand or contract when they are subjected to an electric field. This makes them useful for moving mechanisms such as watches and even as a way to open/close hot water valves in coffee machines. The problem was that one of the best piezoelectric materials we had was lead zirconate titanate (or PZT for short). In order to make the PZT material, the lead had to be sourced in quite large quantities and yet, being toxic and environmentally damaging, it was considered advantageous (even necessary) to remove the lead.

doorway in Kahaila
A painted doorway inside Kahaila in combination with flowers in front suggests a thought train about the way bees see.

However, just like the egg yolk in cookie recipes, you cannot just remove it and produce the same sort of effect in the finished product. You need to understand what role the lead was playing in order to be able to substitute it properly and even then, the effect may not be as good as the original ingredient (without some tweaking elsewhere in the recipe also). Consequently a lot of research has been undertaken in order to find new piezoelectric materials and to understand them so as to optimise the piezoelectric effect. Partly this involves adding the new ingredients slowly to understand their role. Partly it involves changing the growth conditions (somewhat equivalent to the baking temperature) in the crystals that are made. Always it involves experimenting and understanding the role that different ingredients play in our final devices.

Research is still ongoing to find a good substitute for lead in piezoelectric devices. But it goes to show that there are many connections between diverse areas of our experience. Unlike research into piezoelectric materials though, the advantage in experimenting with cakes is that the test of the result is in the eating. Now to experiment with some biscuit recipes…

Kahaila is at 135 Brick Lane, E1 6SB

¹On Food and Cooking, the science and lore of the kitchen, Harold McGee