The art and science of fermented foods with Jenny Neikell

How fermented foods can be a game-changer for gut health

Fermentation is making a comeback thanks to growing awareness of its benefits for gut health and sustainability. Here's part two of our interview series with Jenny Neikell “Surtanten”, Sweden’s leading fermentation expert and advocate for integrating fermented foods into daily life. Jenny shares her knowledge on sources of probiotics and prebiotics, and how fermented foods can be a game-changer for both gut health and sustainable living.

Catch up on the first of our interview series with Jenny Neikell here: Discover the benefits of fermented foods for gut health, with expert tips on safe home fermentation and a delicious recipe.

BioGaia: Thanks for joining us again, let’s dive into the science a bit. Fermentation is both an ancient art and a science, right? What’s happening in that jar during the process?

Jenny Neikell: Absolutely, it’s a balance of art and science. If we focus on vegetable fermentation, like making sauerkraut, the process involves three phases over about 14 days. It starts by preparing the vegetables: slicing, grating, and adding salt. The salt does a few things: it enhances flavour, preserves texture, and creates an environment that supports the growth of beneficial bacteria while suppressing harmful ones. The key is to keep everything submerged in liquid to create an oxygen-free environment, which is essential for safe fermentation.

In the first phase, certain bacteria start converting the sugars in the vegetables into acid and gas – that’s where the bubbles come from. This phase also develops those initial flavours and aromas. After a few days, as the acidity rises, another group of bacteria takes over, focusing solely on producing more acid, which further lowers the pH and makes the environment even safer. By the time you reach day 14, the pH is low enough – around 3.5 – that no harmful bacteria can survive. It’s amazing how the process self-regulates to create a delicious and safe product.

BG: And what about the potential health aspects of fermented foods?

JN: Well as you know, there is a lot of research being done on the connection between bacteria, gut flora, diet, and health, and many exciting studies are emerging.

It’s a complex field, making it difficult to draw definitive conclusions, but many researchers agree that in general, we should consume more live bacteria and it’s important to have a lot of different bacteria in your gut flora.

To me, one interesting way of getting them in there is to eat fermented foods such as lacto-fermented vegetables, yogurt, kefir, and kombucha. There is such a diversity of fantastic, flavourful, tasty foods that we can eat daily, and these can all add to a diverse gut flora.

BG: But what about fermented foods that are heated (like sourdough bread and tempeh), where the bacteria die? Are they still beneficial?

JN: It’s true that the bacteria die, but the microorganisms have already done their job during fermentation. Fermenting microorganisms can break down so-called antinutrients like lectins and phytic acid, making the nutrients in the raw ingredients more accessible to our bodies.

You could say that the fermentation process handles part of the digestion even before the food reaches your stomach. So, there are benefits to fermented foods, even if they are heated.

BG: And talking about bacteria, can you talk us through the differences between probiotics and prebiotics?

JN: One potential source of probiotics comes from fermented foods that make their way to your gut and potentially thrive there. Probiotics are the live bacteria that can travel from your mouth through your intestinal system and hopefully set up camp in your gut, if they survive the whole acid battle on the way down there.

Prebiotics, on the other hand, are fibres that our bodies can’t digest but serve as food for gut bacteria, helping them flourish. Prebiotics are our gut bacteria’s favourite food and are found in many vegetables. Together, these elements create a thriving gut microbiome, essential for overall health.

BG: Storebought or homemade fermented foods? What’s best?

JN: While store-bought products are convenient, they often lack the richness and complexity of homemade versions. I believe the time invested in fermenting foods at home results in deeper flavours and more robust bacterial cultures.

For example, butter; if you make butter at home, you will get so much more of a rich and complex flavour. And that is because butter is fermented; you actually add a starter culture of bacteria to cream and then you let the bacteria eat the lactose.

Then, you ferment the cream and you make butter by whipping it until the buttermilk releases and what you're left with is the pure butter fat and a lot of flavour. This process should take at least 24 hours to ferment and maybe even up to 40 or 48 hours because that gives a lot of flavour development and one of the flavours that is being developed is called diacetyl. It's a ketone and the key to the most amazing, complex and rich flavours in butter. Storebought butter is never given this time to develop as the culture is often added just before transport.

The same goes for homemade sourdough bread; the longer fermentation times lead to improved texture, flavour, and even enhanced nutritional value by breaking down anti-nutrients like phytic acid.

BG: So you recommend trying fermentation at home?

JN: Absolutely! We grew up in a society where we were taught to be afraid of bacteria and microorganisms, that there were our enemies, but they're actually not; they're our friends. These microbes were here long before us, and they're going to be here long after us.

Home fermentation is quite easy if you follow a few simple rules, and you get a much better food source, than you can get in a store.

BG: And how do you view fermentation as a tool for sustainability?

JN: I think this is one of the keys to a more sustainable society; that we have to start to take care of the things when they are in season. Although there are other preservation methods for this, fermentation is really a good a good one because it's so easy and also you preserve the nutrients.

For countries with long winters, fermenting seasonal produce is a simple yet powerful way to reduce food waste and preserve the nutritional value of fresh foods all year round.

In a world facing climate challenges, embracing local, seasonal eating combined with fermentation techniques could be a key step toward more sustainable living.

About Jenny Neikell

Jenny Neikell “Surtanten” is Sweden’s foremost expert in fermentation, lactic acid fermentation, and preservation. She is an internationally award-winning author, and popular keynote speaker. Most recently, she has published ‘The Big Book of Fermentation’ and ‘Ferment: The Cookbook’ with Norstedts Publishing. Jenny regularly holds courses and lectures on fermentation throughout Scandinavia.

Photo cred: Tom Wall