1. noun    A process in which an agent causes an organic substance to break down into simpler substances; especially, the anaerobic breakdown of sugar into alcohol.

One of the most common questions we get at markets is "what is fermentation?" The dictionary definition doesn't really help make things any clearer, so we thought it would be helpful to give a primer on fermentation and the amazing foods it can create. 


Fermentation occurs naturally all around us. It is a remarkable process that preserves food, produces amazing flavors, and has wonderful health benefits. Humans learned to cultivate their own fermented products centuries ago and have been honing and tweaking the process ever since. Some historians speculate that early humans saw chimps drinking from puddles underneath bee hives where the honey dripped out and started to ferment. They may have become intrigued by the chimps’ behaviour and decided to try it for themselves. It is also possible that farmers noticed that cabbage has a tendency to go sour as it gets old and learned how to intentionally develop the sour flavor in the form of sauerkraut. However early humans got their inspiration, people have consumed fermented foods for centuries and have developed amazing varieties of delicious flavors as a result.

At Cauldron, we focus on lactic acid fermentation of vegetables. In this type of fermentation, starches in the vegetables are converted into lactic acid by the bacteria that is naturally present. Lactic acid bacteria are abundant in our environment; the key is to create the best environment for them to thrive and properly ferment your vegetables. The lactic acid acts as a natural preservative that inhibits the bacteria that will cause food to rot. This explains why fermentation was one of the original forms of food preservation for a long winter. Lactic acid is also what gives fermented foods their wonderful tanginess. 

The process of fermentation also gives us beer, vinegar, coffee, wine, bread, yogurt, and many other foods we love. While all of these foods are considered fermented, there are many different types of fermentation. For example, beer and wine are created when sugar is consumed by yeast, which produces alcohol and carbon dioxide as a byproduct. The first alcoholic beverages were made with indigenous yeasts that are naturally present in the air and on the fruits, grains, and fermenting vessels that were used. We have since developed the ability to cultivate specific yeast varieties, which has enabled us to produce an amazing variety of beers with hugely varying flavors. Any homebrew store will have a refrigerator full of yeast varieties that all lend a different flavor to the beer or wine. Many commercial breweries cultivate their own proprietary strain that gives their beer it’s unique taste.

It is, of course, still possible and fun to make make alcoholic beverages with indigenous yeasts as our ancestors did. Each batch will taste different and will give you a truly unique and wild experience.  Most people have experienced fruit juice in the refrigerator that has “gone bad”. This is an excellent example of indigenous yeast fermentation, in which the yeasts that are naturally present in the juice start to ferment the sugars and produce alcohol. Hard apple cider is a great example of a product that exists on the cusp of “good” and “bad”. Some people will throw their cider away when the jug in the refrigerator starts to expand. Others will intentionally let that same cider sit out on the counter to capture more wild yeasts, let it ferment, and then serve the resulting beverage with dinner.

Vinegar is the result of fermentation in which bacteria consumes alcohol and produces acetic acid as a byproduct. Again, this is a process that occurs naturally as a result of acetic acid bacteria that are prevalent in the environment. The same hard cider that we let capture wild yeasts to produce alcohol can then be turned into apple cider vinegar with wild bacteria. Winemakers go to great lengths to make sure their wine isn’t exposed to air and thus to acetic acid.  Wine drinkers will notice that a bottle of wine left open will start to develop a vinegary flavor. This is wild fermentation at work.

Yogurt and cheese are fermented products that require a starter culture to provide the initial boost of bacteria. Yogurt is made by heating milk, allowing it to cool and then inoculating it with specific strains of lactic acid bacteria. The bacteria consumes the sugar in the milk and produces a thick, tangy yogurt. The strains of bacteria that commonly create yogurt thrive in a warm environment, and must be incubated between 105-112 degrees Fahrenheit for the process to work. Other bacteria commonly used to produce cheeses and some yogurts thrive in cooler temperatures and can be cultured around 77-85. While most recipes call for incubating yogurt for around 6 hours, a 24 hour incubation will produce a yogurt where the bacteria has consumed mostof the milk sugar.

Still other ferments, such as kombucha and kefir rely on a SCOBY (Symbiotic Culture Of Bacteria and Yeasts) to catalyze the fermentation. The SCOBY is a physical thing made up of cellulose and contains both acetic acid bacteria and yeast. To make kombucha, the SCOBY is placed into green or black tea with sugar added. The sugar is consumed by the bacteria and yeast and the resulting product is a lightly effervescent, sour drink. Kombucha SCOBYs are commercially available, but it is relatively easy to find a SCOBY from someone who makes their own. Each new batch of kombucha will produce a new SCOBY as the colony multiplies, so it quickly becomes necessary to either find a new home for your SCOBYs or discard them. There are several websites dedicated to swapping various starter cultures and SCOBYs.

Kefir is a milk based fermentation that requires a SCOBY. Instead of using a sweet tea, kefir SCOBY (or grains) are placed in milk. The bacteria and yeast in the SCOBY consume the sugar in the milk, creating a lightly effervescent tangy drink that is similar in flavor to yogurt. Like the kombucha SCOBY, the kefir grains multiply every time you make a batch. Anyone who regularly makes kefir will be happy to share the grains with you!

This post is by no means an exhaustive list of all of the exciting things that can be created by fermentation. There are so many traditional ferments that are beginning to resurface as interest is being rekindled. There are also incredible new dishes being created by adventurous chefs looking for new flavors.  I hope this answered some questions and even piqued interest in learning more about the wonderful world of fermentations.