Fermentation, by Thom Eagle
It has often struck me as odd that Britain possesses no distinct tradition of fermenting food. We use wild or cultivated yeasts, of course, to give life to our beers and our breads; we let cheeses, a vast array of cheeses, quietly follow their own course in the soft dark of caves, of gorges and cellars; where, though, is our kimchi, our choucroute, our sauerkraut, our miso, natto or garum? When we assimilate traditionally fermented foods into our own magpie cuisine, it is often that element which is the first to go; kecap becomes ketchup, and the reassuring tang of sweetened vinegar replaces the complex vegetal aromas of controlled decay.
That last phrase perhaps gives a clue as to why this might be. Although there is nothing particularly hard about fermenting vegetables, either in terms of acquired technique or fine judgement, it can be difficult for the modern cook as it requires letting go of two looming modern fears – of bacteria and of salt. Some bacteria is, of course, very bad; you should always be aware of it to a degree during any food preparation (especially any long, drawn-out process), but extending a justified fear of botulism or e. coli to all bacteria is like refusing to eat any fish because it might be an electric eel. Clearly a line needs to be drawn, and some bacteria is, of course, very good. All you need to do is encourage the good kind, and for that you need salt. Put simply (and very briefly), bacteria doesn’t like salt, and if you heavily salt food it will last well; it will just be unpleasantly salty. Lactic acid bacteria, though, (a good kind), can tolerate more salt than most, and if you salt food moderately these will proliferate, creating an acidic environment even more inimicable to other bacteria; this, although it presumably would not have been understood in such terms, is the basic strategy behind vegetable ferments since the dawn of human history; there is evidence of such foods in ancient Mesopotamia, in old Iceland, the world over.
So. Fermented foods last well, even, under the right circumstances, almost indefinitely. Any more-or-less sterile product will gradually fall away from its original perfection, but a jar of sauerkraut, say, is a living, thriving community which, being in a constant state of flux, never really changes; at any rate, you’re likely to eat it before it does. If you grow vegetables, as we do at the café, then fermentation is an excellent way to deal with the various yearly gluts, as well as with otherwise tough and inedible parts; stalks, outer leaves and the woodiest roots all respond well to the slow transformation of bacteria. We don’t need, really, to store food like this anymore. We have fridges, freezers, cans and clingfilm, and we have access in any case to a near-constant stream of fresh meat, fruit and vegetables; fermentation still has a place because its products are so delicious, and we know they are nutritious, of course. Captain Cook gave his men sauerkraut to ward of the scurvy, and if that is a less present danger in our modern Western society then we have our own problems, many of them caused, ironically, by the increasing fear of bacteria.
The health claims made for fermented foods are many and various; while the probiotic aspect of them seems obvious, I’m not particularly qualified to explore that aspect of fermentation further, and nor do I much want to. The important thing, as I see it, is the flavour. Think of soy sauce or blue cheese. The combination of salt and decay creates an incredible savoury depth which we have learned to call umami; there is a reason why the products of fermentation are used in so many disparate cultures as condiments, to add savour to otherwise bland but filling food. Rice porridge is rice porridge, but with kimchi it can become a meal.
While fermentation, with its ancient roots, its long darknesses and occult practices, might seem deeply mysterious to the layperson, it is actually extremely easy – both easier and quicker, really, than more traditionally British preserving methods. I made a batch of cucumber pickles recently that were ready in a day where a similar style wrought in vinegar would have taken perhaps a month; that’s with hot weather and a dose of luck, though. Still, a week is not unlikely, and the process – at the risk of repeating myself – is really very simple. It has become the thing for food writers to stress the ease and simplicity of their creations, and I know how annoying it is to read a ‘foolproof’ recipe which turns out to be neither easy nor particularly nice; I think we should respect the complexity of craft, and try to rise to it. Nevertheless, fermentation really is easy; there are two basic methods, which can be expressed in the familiar terms of sauerkraut and gherkins.
Sauerkraut is fermented shredded cabbage, and it is made by rubbing or pounding salt into the dry brassica, which breaks down slightly to provide its own liquid. I’d add perhaps 20g of coarse salt to a kilo of vegetable, which could be carrot, kohlrabi, kale stalks, spring onion or fennel rather than white or red cabbage, although the latter performs its own litmus test, turning a rich and pretty pink when it reaches a desirable acidity; for other vegetables, you’ll just have to taste and prod to see when they are ready, which really means when they are as sour and as soft as you want them to be. It’s really up to you. Just make sure nothing is sticking up above the liquid, and you should be fine; the sauerkraut (of whatever vegetable you choose) can live in the fridge when you’re happy with it.
Gherkins are more involved, but only just; you have to make a brine. Boil salt and water, in similar proportions (20g to a litre), just until it is dissolved, then leave the lot to cool and pour it over your baby cucumbers or whatever you happen to have. (Fermented tomatoes, slightly underripe, are very good indeed). While sauerkraut relies mainly on the pungent brassical spice of aged cabbage for its flavour, with perhaps a little caraway or juniper, gherkins, starting out with a much blander base, tend to include more prominent aromats; dill is, of course, the favourite, but you could use fennel fronds or seeds, mustard, horseradish, bay, garlic or indeed anything you like. The brine will cloud over when they’re ready, which might take a day or a week or two.
This vagueness might be irritating (the uncertainty definitely doesn’t lend itself to menu planning) but that is really the point of fermentation; it is an organic process which depends on many things, including temperature, humidity, the freshness and cleanliness of your vegetables and the particular microbial ecosystem of your kitchen, your garden, your soil. To eat a home-made ferment is to eat local on the very smallest of scales, and once you get into the swing of it instructions stop seeming vague and become instead open-ended, inspirational; almost literally. When you make a pot of mixed pickles or fermented turnips you are creating life, a teeming mass of life, and filling your kitchen with it, each jar on each shelf a tiny world.