Exploring Fermentation

The science, safety, and flavour of fermented foods

by Dr. Sarah Nyrose BSc ND

Fermented foods add a burst of sweetness, a bold hit of tart, or sour undertones. They add an extra dimension to any dish, all thanks to the beneficial bacteria that reveal their unique flavours.


What is fermentation? 

Fermentation is when an organism – whether it is bacteria, yeast or mould – produces enzymes that convert sugars in a food into simpler compounds. The process of fermentation lowers the pH and helps to prevent food from spoilage. Fermented foods include sauerkraut, kimchi, kefir, cheese, yogurt, wine, beer and many more. 

At what point in history did we start consuming fermented foods?

The term fermentation is derived from the Latin word fermentum, which translates to “boiling”. The process was coined after the observation that crushed grapes contained in large vessels produced bubbles, as if they were boiling. 

While no one can precisely identify when humans first began to ferment food, the earliest recordings of this process date as far back as 6,000 BC.Fermented milk was noted in ancient recordings from the Egyptians, Greeks, Romans, and Mongolians.

Why fermented foods?

Fermentation became popular because of its ability to preserve food and for the enhancement of flavour. During fermentation, microbes breakdown larger, less flavourful starches into smaller molecules. Our taste-receptors are better able to detect the sweet flavours of these smaller molecules, adding a depth of flavour and an enhanced quality to fermented foods.2

Some fermented foods contain probiotics – the healthy bacteria that maintain the natural balance of microbes in our gastrointestinal system. Lacto-fermented foods contain Lactobacillus bacteria, which play an important role in digestion, metabolism and our immune system.3,4

What’s the difference between rot and fermentation?

There is a fine line between rot and fermentation. Rot occurs when all microbes are involved in breaking food down. Fermentation is a process where only a select number of microbes are encouraged to flourish. 

What do you need to be concerned about with fermentation? 

With fermentation there is the potential for harmful microbes to be introduced. These microbes include, but are not limited to Clostridium botulinum, Escherichia coli, Salmonella and pathological moulds.2  With proper cleanliness and by following specific instructions, you can prevent the contamination of bad (pathological) microbes. Fermentation should not be feared, however it should be conducted with caution and precision. If ever in doubt, throw it out.

Fermenting foods is meant to be a gratifying and exciting process. It’s a means to unlock flavours in food, to explore new tastes, and to use local herbs and ingredients in a unique way.

In our fermentation recipes, we strive to provide clear instructions on cleanliness and proper technique in order to promote a safe and healthy fermentation. The following are our fermentation guidelines for producing safe and delicious fermented foods. 

F&F Fermentation Guidelines

#1—Use a standardized recipe.

We’re often tempted to modify, tweak and combine recipes (I am the first to do this!), but with fermentation you need to be precise and accurate. Often the quantity of ingredients is specified for a reason. For example, while it may be tempting to reduce the salt in a brine recipe, the salt concentration in lactic acid fermentation needs to be 2-3% the weight of the vegetables. The salt is needed to promote the growth of beneficial bacteria; reducing the salt concentration could potentially allow harmful bacteria to grow. Make sure you understand the science and principles behind a fermentation recipe before adjusting it or adapting it for local ingredients. 

#2—Make cleanliness a priority.

Equipment. Work with clean equipment. Make sure that you wash your containers, and sanitize them by running them through the heat cycle of your dishwater, or boiling them for a few minutes. You want to try to remove most of the microbial life such that you’re not introducing any unwanted microbes. When working with your hands, wear vinyl or latex gloves, which help to prevent contamination. The one exception to this is working with lactic acid fermentation – the bacteria from your skin can be beneficial for this fermentation. 

Food. Some fermentation relies on wild fermentation – the growth of beneficial microbes that are naturally found on food and in the environment, while deterring the growth of harmful microbes. Whenever you are fermenting food, make sure to use food that would not have any manure on it, and to remove any dirt and debris. Always remove the outer layer of the produce before starting the

#3—Ensure that fermentation is occurring.

Fermentation should start to occur within 24 to 72 hours. The first sign of fermentation is often the formation of bubbles, which should occur in the first 48 to 96 hours. Another way to check for fermentation is to measure the pH. In most fermentation recipes, a pH of less than 4.6 must be achieved within the first 72 hours, otherwise harmful microbes may establish.5 Always check your batch for signs of spoilage, and if there is evidence of mould, discard the entire batch. With our fermentation recipes we will specify how to monitor your fermentation, and to ensure that things are progressing as expected. Once your fermentation is complete, refrigerate the product. 

#4—Trust your instincts.

Our sense of smell and taste are programmed to detect harmful substances. If something smells funky or tastes off – trust your gut and throw it out. 

#5—Enjoy the process.

Fermenting foods is meant to be a gratifying and exciting process. It’s a means to unlock flavours in food, to explore new tastes, and to use local herbs and ingredients in a unique way. It’s also a fabulous way to incorporate probiotics into your diet for their health and nutritional attributes. Research continues to support the importance of probiotics for digestion, our immune system, and mood. We believe that obtaining probiotics through fermented foods on a regular basis is beneficial. 

While we will be exploring simple fermentation recipes, one of our favourite texts that delves into the history, art, science and nuances of fermentation is The Noma Guide to Fermentation. René Redzepi and David Zilber share techniques for making a wide array of fermented products. It is a book we highly recommend! 

Stay tuned for our kimchi and kombucha recipes, and a continuation of our conversation on fermentation techniques. 

  1. Gogineni, V. K., Morrow, L. E., Gregory, P. J., & Malesker, M. A. (2013). Probiotics: history and evolution. Journal of Ancient Diseases & Preventive Remedies.
  2. Redzepi, R., & Zilber, D. (2018). The Noma Guide to Fermentation: Including koji, kombuchas, shoyus, misos, vinegars, garums, lacto-ferments, and black fruits and vegetables. Artisan Books.
  3. Chilton, S., Burton, J., & Reid, G. (2015). Inclusion of fermented foods in food guides around the world. Nutrients, 7(1), 390-404.
  4. Marco, M. L., Heeney, D., Binda, S., Cifelli, C. J., Cotter, P. D., Foligné, B., … & Smid, E. J. (2017). Health benefits of fermented foods: microbiota and beyond. Current opinion in biotechnology, 44, 94-102.
  5. McIntyre, L. (2016, November) Fermented Food Safety. Presentation for BC Food Protection Association. BC Centre for Disease Control. Retrieved from: www.bcfoodprotection.ca

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