What if we told you there's a fizzy drink that can give you a major energy boost, but it doesn't involve a can containing astronomical amounts of sugar or caffeine - in fact, it's highly nutritious, and can be made at home?

Rachel De Thample says she experienced a "massive wave of energy" when she started drinking kefir, a fermented dairy drink, on a daily basis. It was not long after giving birth to her son, when she'd started to feel "wiped out" all the time.

"That's quite common for new parents, but I just felt like there was something else going on. I was feeling pretty horrid and I went to see a nutritionist and she did some gut testing and found I had no good bacteria in my gut," the food writer says.

Blaming a poor diet growing up in the US, combined with "a lot of antibiotics" she'd taken as a child, De Thample cut out sugary and starchy foods and embarked on "a pretty pure diet, mostly fruits and veg and nuts and a few lean meats and fish.

"Then after I did that for about six weeks, I started to introduce loads of fermented foods to repopulate the good bacteria - the one I first started with was goat's milk kefir from Wales," she recalls.

After enjoying the energy "rushing back", Texas-born De Thample decided to have a go at making her own kefir, which is how her obsession with all things fermented began.

"I did and I just thought, 'Well that's easy'. That really opened the culinary door. Once I started making my own, I realised how much fun it is and how many flavour combos you could start playing with."

Now, the 44-year-old, who started out as a TV news journalist before moving to the UK and making the switch to food writing and training as a chef, has penned River Cottage Handbook No.18: Fermentation, imparting all the knowledge she's garnered throughout the years.

So what exactly is fermentation? "Basically, you're creating an environment where good bacteria can multiply," De Thample explains. She's keen to stress that you don't need to get bogged down in the science if you want to create tasty fermented foods like pickles, sauerkraut and sourdough bread, or drinks like kefir and kombucha.

"I try to explain enough of the basic science in the book, without being too off-putting, because it put me off initially. I just thought, I need, like, a degree and I need a sterilised kitchen and I need special tools - then I realised that all I needed was a jam jar, a pinch of salt and cabbage to make sauerkraut."

She says sauerkraut is the "easiest and the best" recipe for beginners, and the most versatile in terms of how you use it - in everything from lentil salad and potato cakes to Bloody Marys.

To create fermented drinks, you will need some extra ingredients. Kefir grains are what start the fermentation process, whether it's in water, milk or a non-dairy drink, while a 'scoby' (which stands for 'symbiotic culture of bacteria and yeast') gets things going while brewing black tea-based kombucha.

"You can easily order a scoby or kefir grains online, but one thing I always encourage people to do is to use their social media networks," De Thample says. "Most of the time, they'll know someone who has a kombucha scoby on the go, or some kefir grains."

The other key ingredient you'll need? Patience. Kefir requires at least 24 hours inside a sealed jar before it's ready to drink, while most kraut and pickle recipes take about a week to ferment, and you'll need to 'feed' a sourdough starter of flour and water for seven days before it can be used.

Preparation is generally quick and easy though, so if you're willing to wait you'll reap rewards because fermentation "enhances the flavour quite dramatically - it's a double win in terms of the health benefits and the flavour as well", says De Thample.

It's not just your energy levels that might rise when you consume tangy krauts or fizzy fermented drinks.

"With things like pickles and sauerkraut, the vitamin C content almost doubles throughout the fermentation process, and the vitamin A content increases," De Thample adds. "Also you have that boost of good gut bacteria, so you're certainly increasing the biodiversity of your gut as well, so that does help digestion."

She recommends starting with one portion of fermented food a day - and be aware that eating a lot of sugar can have the opposite effective, destroying the good bacteria in your gut.

"I think in general, it's good to be mindful of sugar. If you're having kefir, for example, for breakfast, if you have it with a croissant laden with jam then you're kind of negating the benefits."

One sweet treat you will find in the book is deep-fried 'sourdoughnuts', with chocolate glaze, icing or jam filling.

"I talked to Hugh [Fearnley-Whittingstall, owner of River Cottage, who introduces the book] about it. I just said, 'Is it OK because they're quite fun but it's a bit naughty and most of the recipes are really healthy' - but to be honest, we all like sugar."

De Thample is a fan of following an '80/20' approach to healthy eating, where 80% of the food you eat is "really nutrient dense, and then the 20% is the stuff that just gives you pleasure and joy and helps you be a sociable, happy being.

"You know, you don't want to be sitting on your own consuming fermented foods and nothing else," she says. "It's all about the balance."

Sourdoughnuts recipe


(Makes 8-12)

For the dough:

250g active white sourdough starter

250ml warm whole milk

500g strong white bread flour, plus extra for dusting

2tbsp melted butter

2tbsp raw, organic caster sugar

1tsp sea salt

2 large eggs, lightly beaten

For deep-frying:

1L rapeseed or sunflower oil

For chocolate-glazed doughnuts:

100ml single cream

1tbsp melted butter

100g dark chocolate, finely chopped

For icing-glazed doughnuts:

2-3tbsp warm whole milk 100g icing sugar

For jam-filled doughnuts:

1tbsp jam per doughnut

100g icing sugar

You will also need:

7cm plain round cutter

3cm round cutter (for ring

doughnuts only)

Fermentation time:

8-12 hours, or overnight

Proving time:

1 hour, plus 30 minutes


1. In a large bowl, mix the sourdough starter with the warm milk, flour, melted butter, sugar, salt and beaten eggs to form a smooth dough.

2. Turn out onto a floured surface and knead well for five to 10 minutes until the dough is stretchy. Transfer to a bowl, cover with a damp cloth and leave to rise at room temperature for eight to 12 hours or overnight, until doubled in size.

3. Tip the dough out onto a well-floured surface and pat or gently roll out to a 1cm thickness. Use a 7cm cutter to stamp out rounds. Reroll the trimmings to cut more doughnuts.

4. Cover the doughnuts loosely with a tea towel and leave to prove in a warm place for about one hour until almost doubled in size. When you press the dough gently with a finger, it should bounce back.

5. For jam-filled doughnuts, leave the rounds whole. If you fancy glazed doughnuts with holes, cut out 3cm holes from the centres (you can fry these, too). Transfer the doughnuts to a floured baking tray or board and cover with a clean tea towel. Leave to rise in a warm place for 30 minutes.

6. Meanwhile, prepare your chosen glaze or filling.

For chocolate-glazed doughnuts, pour the cream into a pan and gently heat to just below the boil. Put the butter and chocolate into a bowl, pour on the warm cream and stir until melted and smooth.

For icing-glazed doughnuts, whisk the warm milk and icing sugar together until you have a smooth glaze the consistency of single cream - it should coat the back of a spoon.

For jam doughnuts, put the jam in a bowl and stir to soften it if necessary. Sift the icing sugar into a dish.

Heat the oil in a deep-fat fryer or large, heavy saucepan to 190°C (or until a small piece of dough (cut from a ring doughnut, for example) dropped into the hot oil turns golden in 15 seconds.

7. Deep-fry the doughnuts, one by one, for about two minutes each, until golden. Use a slotted spoon or tongs to turn them in the oil and to safely remove them once cooked. Transfer to a plate lined with kitchen paper or a wire rack to drain.

8. Glaze or fill the cooked doughnuts while they are still warm. With ring doughnuts, dip one side of each into the chocolate or icing glaze to coat generously, then place on a board and leave to set before eating. With whole doughnuts, use the end of a teaspoon to poke a hole in the side then use the spoon to gently ease two to three teaspoons of jam into each one. Roll the filled doughnut in icing sugar until well coated and leave to cool before eating.

River Cottage Handbook No.18: Fermentation by Rachel de Thample, photography by Gavin Kingcome, is published by Bloomsbury Publishing, priced £16.99 (rivercottage.net). Available now.