Dear Readers, during the first lockdown it suddenly seemed as if every second person that I spoke to was experimenting with sourdough bread. I imagine there were many reasons for this – the extended period at home meant that the starter could be nurtured, for one thing. For another, there’s something about kneading the dough that is very therapeutic – I have certainly gotten Zoom calls out of my system by being overly assertive during bread-making. And then there’s that sense of connection with all those generations of bread-makers who went before. The fact that many of my loaves turned out like slightly-more-porous bricks didn’t take away from the sense of accomplishment – at least the bread had the right smell and appearance (generally).
But what I hadn’t thought about was that sour dough in particular actually gives us a connection not just to our ancestors, but but to the unique microorganisms that live in our houses, and even on us.
In New Scientist, someone raised the question of why sourdough tastes so different in San Francisco compared to the loaves in London. To understand why, it helps to know a bit about the process of making it.
Most bread (including my bricks) is helped to rise using commercial yeast, either fresh or dried. But sourdough is different. Water and flour are mixed together and then exposed to the natural microorganisms in the air. The yeasts produce the carbon dioxide bubbles as they respire – this is what enables the bread to rise during proving and cooking. But other bacteria (particularly from the Lactobacillus genus) produce lactic and acetic acid, which contribute to the flavour. The flour also contains bacteria – as you might expect, the less processed the flour, the more opportunity for microorganisms to survive, and to contribute to the flavour of the finished load.
Then, there are the bacteria that live on us, particularly our hands (hence all the calls for increased hand washing during the pandemic). Some people swear that the loaves made by a particular baker can be identified purely by the taste that their bacteria impart. This is about as far as you can get from the identical loaves created in supermarkets and commercial bakeries.
The amount and type of water added to the loaf will affect the final result – a wetter loaf makes it easier for the dough to rise, but the flavour of the water will also add its own special twang. Plus, sourdough needs a long, slow fermentation, and during this process different microorganisms will thrive or die, according to the conditions in which the starter is kept – different temperatures will affect different bacteria.
As the loaf containing the starter is baked, the yeasts first go into overdrive because of the heat, producing the carbon dioxide that contributes to the rise. But as the heat continues to increase, the yeast can no longer metabolise and finally they die, along with the vast majority of the bacteria. It seems like a poor reward for all the work that these microorganisms have done, but it’s all the better for us humans.
However, the rest of the starter remains.It’s easy to forget that a sourdough starter is actually a living thing, a community of microorganisms. The starter should be fed regularly and can last for years if properly looked after. Maybe this is part of the reason for the whole sourdough phenomenon – the sense that what is being made requires careful nurturing and is also completely individual must add to the pride at the finished result. No wonder that, in Sweden, a ‘sourdough hotel’ was set up to look after your sourdough starter when you went on holiday, feeding it with the requisite amount of flour and making sure that it didn’t dry out.
So, over to you readers. Have you been ‘sourdoughing’ during the pandemic, or before? I am tempted to give it a go, but oh! the responsibility. I know that the whole phenomenon has taken on the aura of extreme middle-classness here in the UK, with the notion that sourdough can only be created if you have an Aga and a man-bun (if you’re a chap) and if you holiday in a yurt (presumably taking your starter with you), but I do know some perfectly non-yurty people who swear by the whole process. Let me know what you think!