Culture club: the facts of fermentation

by Jess Carter

06 October 2017

With winter on the horizon and a culinary dry spell in the distance, we went on a fermentation course to find out more about this rather clever preservation method...

Like with clothes, music and any other sphere that sees trends come and go like they were caught in revolving doors, the food scene is often shaped by different movements. And again, as with other fashions, they’re rarely brand new. Fermentation has been described as a ‘trend’ in the food world for some time now, getting more and more air time on cookery shows, restaurant menus and, of course, in rags just like this one. The thing is, though, that while its popularity has seen it brought to the fore, there are people around the world who have never stopped making and eating fermented foods. Including here in the UK, even if we don’t think about it when we tuck in. Yoghurt, beer and sourdough bread are, of course, all examples of popular fermented produce.

Fermentation itself dates back, it’s thought, to thousands of years BC. So: old news, right? Before we were able to cultivate and import fruit and veg all year round, people would preserve and ferment their seasonal gluts, to make them last into the less hospitable months, when very little would grow. Although it’s remained common practice in some countries, in the UK most types of fermenting have become a bit of a lost skill.

Trained biologist Lucie Cousins is one of the most obvious people to talk to about this topic; having started Bath Culture House last year, she makes everything from kombucha to tempeh and sauerkraut, and runs courses at Demuth’s Cookery School in Bath on the subject – one of which we went along to.

Lucie first got properly acquainted with foodie bacteria whle working as a cheesemaker, where she was producing mould- ripened cheeses. She learned how to maintain bacterial cheese cultures and grow moulds on Camembert and Brie.

“Fermentation is a metabolic process in which an organism (yeast or bacteria) converts a carbohydrate (such as starch or sugar) into an alcohol or an acid,” Lucie says. “Yeast performs fermentation to obtain energy by converting sugar into alcohol, while bacteria perform fermentation by converting carbohydrates into lactic acid. More simply, fermentation is the breakdown of glucose to form alcohol and carbon dioxide.

“I see it as a pre-digestion process, where a large complex carbohydrate is broken down into its smaller parts, therefore aiding our digestion of it, and allowing the nutrients to be taken up into our bodies more readily.” Of course, it’s health benefits like this that have no doubt helped fermented foods to shimmy into the spotlight in this age of rising awareness of food and wellbeing.

“The action of breaking down carbohydrates and pre-digesting the foods prior to eating makes it easier for our bodies to absorb nutrients and food,” says Lucie. “The bacteria and yeasts which are present in fermented foods are also beneficial to our digestive system, which is often historically referred to as our ‘second brain’. A happy stomach equals happy mental wellbeing.

“As we consume these bacteria and yeasts, we improve our gut flora (I see it as tending a lawn within our digestive system, maintaining good bacteria and yeast rather than bad and toxic bacteria). These good bacteria and yeast that live in our guts once again aid digestion within our bodies, helping us take up nutrients, remove toxins, prevent disease, improve our immune system health, and more.

“Geeky fact: there are more microbes in your body than cells; our gut contains around 100 trillion microorganisms!” (There you go, folks. You’ve probably learnt something new for the day now – so you can put your feet up and relax.)
“The process of fermentation in foods increases the amount of B vitamins, folic acid, choline and glutathione. B vitamins are important for brain function, energy and heart health; folic acid benefits the brain and many systems within the body; choline helps the body regenerate cells; and glutathione is an antioxidant.”

So, have we talked fermented foods up enough now that we’re all totally sold, and can move on to the subject of mould? ’Cause that’s where we’re heading...

During the course, Lucie brings out a block of tempeh to marinate and cook. Tempeh is a soya bean product that’s basically bound together with mould that’s been left to grow around the beans. (Stay with us.)

“The process is very similar to fermentation, involving yeast and bacteria, though rather than using wild ferments and cultures found on the outside of fruits and cabbages, as we would with sauerkraut and kimchi, the mould is introduced as a culture: R. oligosporus. This mould is activated when added to soya beans and germinates, growing around the soya beans to create a mycelium network (which is very similar to the growth of white mould on a Camembert or Brie).

“The mould, as it grows, releases enzymes which then pre-digests the basic nutrients of the soya bean. The rhizopus moulds produce an enzyme which breaks down phytates, thereby increasing the absorption of minerals such as zinc, iron and calcium. This process softens the beans too, making them easier to digest.”

Before anyone starts to reach for that stale crust in the bread bin though, mould is, of course, not usually good for us. You’ve not been chucking out funky-smelling jars of stuff for no good reason.

“This mould, grown for tempeh, is speci cally grown within a lab, from original cultures found on Hibiscus leaves. It has been tested microbiologically to ensure no pathogens are present,” Lucie explains.

Okay, so it’s understandable to be cautious when growing moulds, especially seeing as we don’t really get taught to prepare food in this way – for such an ancient practice, it’s relatively unfamiliar to most of us. If you do fancy giving it a go, though, Lucie recommends starting with sauerkraut – which is basically cabbage and salt, and takes two to three weeks to ferment – or milk ker, which is almost like yoghurt (it can be made from cow’s milk or a non-dairy alternative), and takes a couple of days.

As we learn in the class, though, you do have to ignore all you’ve been taught about going easy on the salt. It’s important you get plenty in there.

“Not adding enough salt, or allowing oxygen to get in contact with the fermenting vegetables and fruit, can allow spoilage bacteria and yeasts (non-desirable microbes) to grow,” Lucie says.

And the two are connected: salting the cabbage makes it release liquid, which is what the cabbage needs to be submerged in, in order to properly ferment.

“It is important that the brine naturally produced when salting shredded cabbage always remains above the top of your ferment. This prevents oxygen from getting in contact with the ferment and non-desirable microbes from growing. It also aids the naturally healthy fermentation from the naturally occurring lactobacillus bacteria growing on the outside of the vegetables.”

Similar to sauerkraut is kimchi; a spicy Korean side dish of fermented vegetables. A classic kimchi will include Chinese leaf cabbage, onion, garlic, ginger and chilli.

But there is plenty of room for variation, explains Demuth’s tutor Lydia Downey, who joins us on the course to share her corker of a recipe. ( Get it here! )

“I mainly make traditional kimchi, but also love to use more local veg, such as red cabbage with carrot,” she says. “This results in a quite different style of kimchi, similar to sauerkraut, and is really good to eat as a condiment and mixed into salads. However, it can be made with any vegetables that are good eaten raw in salads; cucumber, radish (particularly white mooli or daikon), spring onion, and carrot are all good.

“To make kimchi taste authentic, you really do need to get hold of some gochugaru (Korean chilli flakes); it’s easy to get in most Chinese and Thai supermarkets these days. I buy it locally in Bath, and also know it’s available in the Chinese shops in Bristol. It has the most beautiful deep rich red colour and flavour that isn’t as fiery hot as you’d imagine.”

It’s gochugaru that gives the kimchi its fab red colour, in fact. It also has a gentler heat, meaning you just won’t get the same result with regular chilli.

Kimchi doesn’t have to be just a simple side, either; it can be used to cook with, and form the base of all kinds of dishes.

“My favourite recipes to use kimchi in are the ones I teach on my classes at Demuth’s,” Lydia says. “Mungbean pancakes are a winner with everyone I’ve taught them to – delicious and nutritious and so simple. Also, you can use kimchi as the starting point of a dish in place of the usual onion, garlic, ginger combo. I gently fry off a couple of tablespoons of chopped kimchi, before adding other veg for stir fries or stews. It gives a fabulous depth of flavour, with that slightly sharp fermented tang which really freshens up a dish. It also makes the most amazing fried rice and, bizarrely, the best cheese toastie in the world! Hey, don’t knock it till you’ve tried it...”

To find out about Demuth’s courses, including this fermentation one, visit the website ; follow Lucie and Lydia on twitter