The power of fermented foods

The Gut Stuff share their ultimate guide to one of the best healthy-eating trends

Fermented foods have been around since Neolithic times. They're often associated with a hefty price tag (we're talking about £8 quid for a jar of salted cabbage!) making them something many of us wouldn't even think to put in our shopping baskets.

However, they don't need to be expensive and once you've learned the basic principles, you can make fermented foods really easily at home.

A note about shop-bought ferments: always check that they contain live bacteria and aren't pasteurised, otherwise you lose the potential benefits that the community of microbes bring.

We know diet can have a huge impact on our gut microbes (diversity and fibre being key players for 'team gut') and we are just starting to learn about the importance of fermented food.

Why ferment food?

Historically, food was fermented to preserve it for later consumption (often by just making a brine with salt). Due to the bacteria and yeasts, fermented food is also tasty and may, in some ferments, increase the food's nutritional value.

When bacteria and yeasts ferment food, they produce something called metabolites. These metabolites include lactic acid, vitamins and exopolysaccharides (sugar molecules) and may support our health (we are still trying to understand how and why). Lots of different foods can be fermented, such as vegetables, cereals and even fruits.

The microbes and their by-products present will depend on how and where the ferment is made (man-made versus homemade having very different qualities), how it's stored and what it's made from.

What do fermented foods do for your gut?

There are some studies looking at the effect of fermented food on the gut, but not any in large cohorts (lots of people).

In one study, researchers analysed 6,811 stool samples and 115 individuals from the American Gut Project were recruited for how often (or not) they ate fermented (plant-based) food. The research analysed:

Gut microbe diversity: Statistically, significant differences were found between those who ate fermented foods and those who did not.

Taxa (species): Different taxa were found between the two groups.

Metabolome (small molecules from a biological sample, including products produced by gut microbes): More conjugated linoleic acid, thought to be beneficial to health, was found in those who ate fermented foods than those who did not.

This is just a snapshot of some of the interesting research (and largest) in the area of fermented foods. Because of their live and individual nature, they are really tricky to pin down and experiment upon in a real-life setting.

What foods can I easily ferment at home?

The brilliant thing about fermenting is that with a few straightforward techniques they are cost effective and simple to make, with plenty of vegan options. They come in varying levels of complexity, but a great place to get started is with lactofermented vegetables such as sauerkraut or kimchi.

Sauerkraut, German for 'sour cabbage' is finely sliced cabbage fermented with lactobacillus bacteria. The sugars in the cabbage are converted into lactic acid and serve as a preservative. We like ours topped on herby potato salad for an added tang.

Kimchi originates from Korea dating back over 3,000 years, where salt was used as a method of preserving vegetables during the cold winter months. It typically contains cabbage and flavourings like garlic, ginger, and chilli peppers. Many recipes call for types of preserved seafood, but vegans can switch this out and supplement with tamari to add a bit more funk.

For the more advanced fermenter, refreshing tonics such as water kefir and kombucha are a good place to go next. These ferments both use cultures referred to as 'grains' or a 'SCOBY'.

The cultures feed off the sugar in the ferments, transforming to a small amount of alcohol, acetic acid and carbon monoxide while the microbes multiply.

They are a great alternative to fizzy preservative-laden drinks. Adding a sourdough starter to your fermenting toolbox is a must for the avid at-home baker.

A traditional sourdough is a live culture of flour and water, referred to as a 'mother' or 'starter' containing a blend of bacteria called lactobacillus and yeast.

These bacteria produce beneficial by-products to keep your gut happy. The minerals iron, magnesium and zinc are also made more available by the fermentation process.


A healthy sourdough starter can be kept for ages with minimal maintenance, ready to have on hand for whenever you are ready to bake.

Once you've got the fermenting bug and have conquered the basic principles it's time to get experimental with flavourings and ingredients. There's so much room to get creative whilst also increasing variety - music to your microbes' ears.

What foods can I easily ferment at home?

Get kit ready: You'll want to think about what kit you'll need to gut fermenting at home. You don't need much but the essentials are a glass jar, and some muslin.

The Gut Stuff's mission is to make caring for your gut accessible to everyone, which is why we are about to launch our 'All in One Fermenting Kit', which has everything you need from jars, burping lids and handy troubleshooting content to support you in understanding how to ferment at home and how to easily add fermented foods to your diet.

These kits demystify the occasionally unpredictable (remember the bacteria is alive!) process of fermentation and make it something that everyone can get involved with.

Hygiene: You need to make sure all your equipment is thoroughly cleaned, so you don't harbour unwanted microbes in your ferment (no double spoon dipping!).

Be realistic: Start with one ferment and go from there.

Management: Think of your ferment as a companion animal, you need time to look after it and check how it's getting on. Don't start a ferment before you go away on holiday!

What should fermentation newbies be aware of?

Perhaps one of the most common misconceptions around fermenting is the level of difficulty. Once you've got your first jar of sauerkraut on the go, you're over the biggest hurdle. After that, it's all about trial and error whilst not being afraid to experiment.

One factor that causes the biggest variation to your ferments is the time of year. The cold winter months will slow fermentation while the warm summer months will speed it up. Whatever the time of year, it is important to keep your ferments out of direct sunlight.

It is likely that all fermenters will, at some point, encounter mould, it's important to know the difference between mould and Kahm yeast. A thin, white, crinkly film with no fuzz is often yeast.

Kahm yeast can be skimmed from the surface and the ferment will still be safe to eat. Mould is raised and fuzzy, it can be black, white, green pink or blue. Should mould crop up, throw the whole ferment away.

As you begin to ferment more it's a good idea to keep a fermenting schedule, we have a great fermenting schedule magnet for your fridge, which is included in our Gut Planning Kit (available in our shop thegutstuff.com/shop).

Available as a set of three - a shopping checklist, meal planner and ferment checklist - these guides are a perfect way to help you more easily build ferments into your day to day life helping you keep track of what you started and when, as you'll see them every day as a reminder.

How can you include more fermented foods in your diet?

Whatever stage you're at, incorporating ferments into every-day life can be simple. Here's a few ideas to get your started:

1. Switch preservative-laden drinks (they don't do your gut bugs any favours) to flavoured water kefir or kombucha.

2. Have a couple of jars of fermented vegetables in the fridge ready to add a serving to meals, this is also a great way to add variety, too.

3. Swap white or wholemeal bread for sourdough bread.

4. If you're short on time, fermented garlic is one of the easiest at home ferments. We add ours to homemade houmous.

The Gut Stuff's All-in-One Fermentation Kits are available for pre-order now, from thegutstuff.com



The lifestyle magazine written by vegans for vegans.