Fermentation: River Cottage Handbook No.18

By Rachel de Thample

Winner of the Guild of Food Writers Specialist or Single Subject Award 2021

In Fermentation, Rachel de Thample shines a light on one of the oldest methods of preserving food, which is just as relevant today, and shows you how to produce delicious and health-boosting ferments in your own kitchen.

There are more than 80 simple recipes to make everything from sauerkraut and sourdough, kimchee and kombucha, to pickles and preserves, accompanied by thorough explanations of how the fermenting process works. With little more than yeast and bacteria, salt and time, a whole realm of culinary possibilities opens up.

With an introduction by Hugh Fearnley-Whittingstall and plenty of helpful step-by-step photographs, this book will bring the art of fermentation to your kitchen.

• Language: English
• Publisher: Bloomsbury Publishing
• Release date: Sep 3, 2020
• ISBN: 9781526612502

Rachel de Thample

Rachel de Thample has worked in the kitchens of Marco Pierre White, Heston Blumenthal and Peter Gordon. She is the author of More Veg, Less Meat, FIVE, Tonics & Teas and Gifts from the Modern Larder. She's served as Commissioning Editor of Waitrose Food Illustrated and Head of Food for the pioneering organic box scheme Abel & Cole. Rachel is currently runs preserving and fermentation courses at River Cottage in Devon and writes for The Simple Things magazine. She lives in Dorset.

Book preview

For my mother, Jeannine

Contents

Fermentation Basics

Vegetables

Fruit

Drinks

Sourdoughs & Batters

Dairy & Dairy Alternatives

Useful Things

We are so far removed from the natural world these days – from the fundamental, organic processes that govern living things – that fermenting can seem like an obscure mystery at best, a risky business at worst. It is not difficult to perceive it as an arcane art, somewhere between alchemy and high science, and not an activity for ‘normal’ people.

If that’s where you’re at, then this book makes a fantastic case for a new normal. Or rather, a very old normal. Because fermenting is one of the most ancient and most widely used food (and drink) preparation techniques there is. In cultures across the globe, in almost every kind of environment and climate, people have harnessed the power of natural fermentation in order to preserve and enhance their produce – to make it safer, more delicious, more nutritious.

Right now, home-fermenting couldn’t be more relevant or important. We stand at an intersection where new knowledge about our health, our society and our economy have combined to compel many of us to re-assess what and how we eat. A desire for the unrefined whole foods that are the key to our well-being, a growing understanding of the importance of gut health – crucially supported by ‘live’ fermented foods – and a renewed appreciation of the fragile nature of our food supply, all lead quite naturally to the idea of preparing and preserving fresh, seasonal ingredients at home.

I began my own fermenting journey several years ago, massaging sea salt into shredded white cabbage from my garden. In terms of smallholder pride, the resulting sauerkraut ranks right up there with the first egg from my own chickens. Now I am a fully paid-up convert, a bit of a fermenting geek (though not in the same league as the author of this book) and proud of it. I love the tangy, savoury flavours of fermented veg, the delicate fizz of kombucha, the wonderful texture and subtle piquancy of good sourdough bread.

But there is much more to my fermenting-fandom than mere taste. In recent years, I’ve seen how eating natural, whole and live foods can transform the profile of our gut bacteria – and how utterly vital those bacteria are to every aspect of our health. I eat and drink delicious fermented things daily, and I’m quite sure that my health is considerably better for it. In fact, fermented foods are now so central to my sense of well-being that I’d feel quite distraught without them.

Fermenting is fun and fascinating too. There’s a real sense of wonder in observing those first tiny bubbles appearing in a jar of salted veg, or handling the frankly weird little globules of a kefir starter (which are like nothing else on earth). And you might also find that an unexpected sense of empowerment – liberation, even – can come from producing your own home-fermented goodies. It’s definitely one in the eye for the food industrialists. Harnessing one’s own creativity, along with the mighty forces of nature, while by-passing the people who put things in plastic packets (and tell us we simply must buy them) feels pretty good, I find.

Rachel de Thample is absolutely the best person I know to introduce you to all this. I’ve worked with her for several years and I never fail to be inspired and enthused by her knowledge and her passion. Rachel leads our courses in fermenting at River Cottage HQ. She is also a dedicated forager and a lover of all things natural and organic.

As an expert fermenter, Rachel has a deep understanding of both the history and the science behind this simple art. But she brings something fresh to this field too; she has a wonderful way of talking and writing about fermenting, opening it up in the most playful and enabling way, dismantling any sense of complexity or impenetrability. She knows anyone can succeed at fermenting – and her enthusiasm and experience make her the ideal teacher. Rachel’s methods here are among the simplest you will find, and her recipes among the most delicious.

So please, don’t shuffle fermenting to the bottom of your culinary in-tray, or file it under ‘maybe, one day’. Instead, let Rachel take you by the hand, and with the best ingredients and the most basic of equipment, you will soon have your shelves lined with happily bubbling ferments and your fridge stocked with irresistible, meal-enhancing lacto-fermented delights.

In the time it takes to start your first jar of kimchi or your first homemade yoghurt, you can join a worldwide community of home-fermenters, all producing foods that represent a great global tradition. At the same time, you’ll know that these living foods, each with their unique fermented fingerprint, could hardly be more local, or more distinctively your own.

Hugh Fearnley-Whittingstall, East Devon, March 2020

Our kitchens are full of magic just waiting to happen. Fermentation is a transformative process that makes food not only more nutritious but also more delicious. It’s one of the oldest ways of preserving, and is surprisingly simple and low-tech. You don’t need fancy kit – just some basic knowledge about quantities and timings. In fact, one of the things I love most about fermenting is how minimalist it is. Its essence is in using what’s already around you – be it natural yeasts and bacteria in the air or basic everyday ingredients, including food scraps and trimmings that might otherwise go to waste. Fermenting is also incredibly addictive, in a good way.

All food contains bacteria – beneficial strains as well as neutral and harmful ones. Perhaps surprisingly, fruits and vegetables are home to lactobacillus, the same good bacteria you find in yoghurt. The principle of fermentation is to create conditions that allow those good bacteria to proliferate. And doing so is very easy: add the right amount of salt, control exposure to oxygen and keep your budding ferment at the right temperature and the good guys not only thrive but out-compete any bad bugs, thereby preserving the food.

There is an increasing understanding in the world of science and medicine of just how important beneficial bacteria are. We have an extensive and varied population of microbes in our guts, known as the ‘microbiome’, and researchers now know that those busy bacteria are hugely important to our well-being, affecting everything from digestion to immunity – probably even mood and mental health. While scientists are still trying to pinpoint exactly which strains of bacteria do what, the general consensus is that the greater the number of different bacteria we have, the better.

Biodiversity is increasingly recognised as critical to the survival of larger-scale ecosystems and it is just as important at the micro level. Eating ‘live’ fermented foods is one brilliant way to promote that diversity in your body. Our bodies benefit from regular top-ups of good bacteria, so the more fermented foods you can introduce into your diet, the better. I try to consume at least one fermented food daily, if not with every meal.

Fermented foods are probiotic, which means they add to the beneficial bacteria normally present in the gastrointestinal tract. You can consume them alongside tablet probiotic supplements or as an alternative. The positives for consuming a regular dose of fermented foods for me include better digestion, more energy and healthier skin. As well as gut-healing benefits, some ferments make minerals more bioavailable, which means the naturally occurring minerals are absorbed by your body more easily.

Fermented foods also teem with tastebud-tingling flavour molecules. Umami, the alluringly addictive and deeply savoury fifth taste (alongside salty, sour, sweet and bitter), is inherent in most fermented foods. It’s no accident that many of our favourite treats are fermented ones: chocolate, cider, wine, bread, cheese, coffee, tea, miso, vinegar, salami… These are ingredients many of us love and that add a real punch of flavour to countless dishes.

Fermenting food and drink using the wild microorganisms present in the immediate environment is an ancient practice that humans have been performing for many centuries. Fermented foods play an important role in feeding the world’s population on every continent: Curtido, the Salvadoran take on sauerkraut, Indonesian tempeh, Slavic kvass, Middle Eastern torshi pickles, Indian dosas, a Mexican-inspired drink called tepache… the list travels on. Unfortunately, the modernisation of food and our food systems has stripped a lot of these foods from our everyday diets. Fermented foods are living and constantly evolving, which makes them less attractive for large retailers, in part because they do not have a definitive shelf life.

By creating your own ferments you will not only be creating living foods to contribute to your diet, but you also become part of an ancient and venerable tradition. Nurturing a ferment, such as a jar of kraut or live culture like a sourdough starter, brings a fantastic sense of continuity and circularity. Established starters and cultures don’t necessarily produce better ferments than younger ones but there is something hugely satisfying about keeping a culture alive and well and even sharing it with fellow fermenters. It’s just one of the things that makes the process of creating your own ferments as pleasurable as actually consuming them.

It’s almost impossible not to get a child-like giddiness upon opening a bottle of ginger beer you’ve brewed yourself, for instance. It’s thrilling that, by simply mixing ginger, sugar and water together in the right order, you can magic up a bottle of vivacious bubbles. Some ferments are very quick, too, like water kefir. It takes just a couple of days to create this healthy alternative to sugary soft drinks and there are endless flavour combinations you can brew up.

This book will take you on a culinary adventure into the many varied realms of fermenting, from a colourful array of kimchis and krauts through probiotic pickles, homemade vinegars and healthy homebrews, to sourdough breads (and cakes) and delightfully digestible dairy. I will share skills and secrets gleaned from many years of experimenting in my own kitchen and at River Cottage, enhanced by the inspiration and creativity of a host of fellow fermenters. You’ll learn all you need to know to get started, master the basics and branch out creatively into new avenues, reaping multiple rewards along the way.

The science

‘Fermentation’ describes the chemical conversion of sugars to alcohols or acids, via the action of bacteria and/or yeasts. There are three types of fermentation: lactic acid, ethyl alcohol and acetic acid, all of which result in sweet tastes changing into tangy, sharp or sour ones.

Fermentation will not happen without bacteria, yeast or moulds. To kick-start fermentation, you must either add live bacterial cultures to the raw materials you wish to ferment, or encourage the bacteria and yeasts already present in the food to multiply by providing the right conditions. Temperature is crucial (see here), as is oxygen or the lack of it.

Some ferments need to be exposed to air (aerobic conditions). This leads to the creation of acetic acid, as in the case of vinegar, kombucha and kefir. Other ferments, including pickles and alcoholic drinks, must be locked in an airtight vessel and starved of oxygen (anaerobic conditions), which creates ethanol and lactic acid.

For lactic acid ferments, such as sauerkraut, kimchi and traditional Polish pickles, salt is crucial. Not only does salt help strengthen pectin present in vegetables, giving you a crisper pickle, it also raises the acidity and creates an environment that is antagonistic to harmful pathogens and bacteria such as Clostridium botulinum, which is responsible for the illness you’ll probably know as botulism. Scientist call this ‘competitive exclusion’.

In most cases, a lactic acid fermentation left longer than a week will reach a pH a lot lower than 4.6 with most going as low as 3, a pH level at which botulism spore cannot produce their illness-bearing toxins. To reassure you about the safety of fermentation further, according to Fred Breidt, an American microbiologist and fermentation specialist, ‘There has never been a documented case of foodborne illness from fermented vegetables. Risky is not a word I would use to describe vegetable fermentation.’

For the production of alcohol and bubbles and fizz in the various fermented beverages you’ll find in Drinks, sugar is key. Yeast or bacteria reacts with the sugars, which in turn creates ethyl alcohol and carbon dioxide. Fermentation does not produce a liquor with greater than 12–15% alcohol because the yeast is killed by higher alcohol percentages. For an alcoholic product such as whisky, distillation is required to remove water from the alcohol until the desired proof (strength or concentration) is obtained.

Understanding fermentation

There are three types of fermentation: lacto-ferments, ethyl and acetic. Knowing which category your ferment falls into will help you understand what you need in terms of food – be it sugar, yeast or ethanol (i.e. alcohol) – and atmosphere. Some ferments require air (aerobic) while others need to be starved of oxygen (anaerobic) in order to kick-start the fermentation process.

Active sourdough starter

Kit

Fermenting is the second oldest form of preserving food, after drying, and was practised long before there were retailers selling kitchen gadgets or grocers offering specialist ingredients, so it stands to reason that it doesn’t call for a lot of special equipment. In all probability, your kitchen will be equipped with all you need to get started.

I do have a fermenting crock – a vessel designed specifically for sauerkraut, kimchi and pickles. It’s a beautiful piece of pottery with a lid and weight to press all the vegetables under the brine, but I find jam jars more appropriate for most modern-day purposes.

Glass jars Most glass jars are suitable for fermenting, and they don’t need to be new. Basic 200g, 340g and 500g jars are ideal for things like kraut and pickles. If you’re making a more classic style kimchi, a 1kg jar is best. Sturdy glass jars can be used over and over again, as long as they are perfectly clean and not tarnished with stains or chips.

Lids These are essential for sealing your jars of ferments and can be reused as long as they are not corroded. Salt will rust metal lids, so ensure your lids are coated on the inside rather than being fully metal. Even coated lids may start to rust after a while; you will need to replace them with fresh ones if this happens. Jars with screw bands are wonderful for fermenting kraut, kimchi and pickles – provided they have coated lids – but I find the flip-style Kilner jars with rubber rings aren’t as good because they have a little pocket at the top that exposes your ferment to a touch of air. Even if you’ve sealed the jar, there’s a gap between the top of the brine and the top of the jar, which can make ferments go off more easily.

Fabric You will need fabric to cover aerobic ferments like sourdoughs and to strain ferments such as drinks and dairy products. It