lactic acid fermentation

The flavourful space between fresh and rotten

“Microorganisms frighten us: aren’t these germs responsible for deadly scourges (tuberculosis, plague, cholera, typhoid)? Aren’t they responsible for serious food contamination? Down with the one-celled organisms, we say! Long live disinfection! Germicides, fungicides, antibiotics, antiseptics, sterilisation, freezing – we lack no weapons in the war against germs. Medicine, agriculture and the food industry make use of them all. We should consider not to kill microorganisms but rather make them our friends and allies.”

Claude Aubert
Kombucha and water kefir brewing in my kitchen

Kombucha and water kefir brewing in my kitchen

Fermentation is the oldest known way of preserving food. The earliest mention of fermentation as a means of food preservation dates back to 7000-6600 BCE in Jiahu, China.  Fermented foods are present in all world diets: In Europe one finds sauerkraut, beer, wine, cheese, meats and pickled cucumbers; in Russia and eastern Europe there are a vast variety of pickled vegetables like peppers, tomatoes, mushrooms; in Japan, Korea and China one is served pickled vegetables or kimchi with nearly every dish as well as pickled eggs, soy sauce and tempeh; in America relishes such as cucumber and corn relish are common; in India we find chutneys and sour milk; in Africa, fermented millet porridge and cereal beers.

Fermentation occurs in yeast, bacteria and lactic acid fermentation and different forms of fermentation require different environments. Yeast cells love being around air as long as sugars are available for consumption whereas the traditional pickling method of using salt brine calls for an anaerobic environment.

Fermented foods go under another name: probiotic foods. Probiotics, or “good bacteria”, grow on and in the food during the fermentation process and they are great for the body in a host of different ways. The word probiotic even means “for life”!

There are too many benefits of probiotics to explore in depth without writing a small book, but here is a brief outline of the health benefits of probiotics and a simplified explanation of the science behind it: One thing probiotics do is to aid digestion as the probiotic foods add to the bacteria flora in the gut and intestine, helping the stomach break down foods properly and reinforcing the stomach lining so that the body can extract and utilise the properties of foods more easily, for instance by liberating antioxidants from the food.
Probiotics are also shown to lower cholesterol: the liver uses cholesterol to make bile, but as probiotics break up bile salts this decreases their reabsorption in the gut.
Studies show that the probiotic bacteria lactobacillus reuteri helps kill the bacteria that causes tooth decay.
Probiotics help balance the bacterial flora in the vagina and thus reduces the risk of infections.
Probiotic foods promote better skin, less acne and redness as they reduce the overall risk of inflammation in the body.
Whether you're constipated or suffer from diarrhoea, probiotics can help for both. Good bacteria can help your body fight the "bad" bacteria causing your diarrhoea, while the probiotic strain bifidobacterium lactis BB-12 converts prebiotic fibres into short chain fatty acids which lubricate your gut and stimulate bowel movement.
A healthy gut flora will also produce substances such as spermine, putrescine and spermidine that kill free radicals and give your immune system a boost. A healthy gut flora has the ability to bind and remove harmful heavy metals and toxins from the body, again lessening the chances of generating free radicals.

I absolutely love fermented foods and I would like to share with you my four methods of home fermentation that I personally know and love – brine pickling, kombucha, fermentation using tibicos and fermentation using whey – how they create probiotics and the pros and cons of these methods.

Brine pickled garlic, golden beets, tomatoes and cucumbers

Brine pickled garlic, golden beets, tomatoes and cucumbers


The fermentation process in brine pickling begins when vegetables are submerged in salt brine. The bacteria on the vegetables, mostly lactobacillus, thrive in this environment and they grow while suppressing the growth of other bacteria that would normally spoil the food. The “good” bacteria, as we can call them, eat the sugar in the vegetable and produce lactic acid, carbon dioxide and alcohol: this process is called lactic acid fermentation. The vegetable is still left with all its fibres and vitamins – it actually gets a vitamin boost!
One can also add vinegar into the mix as the combination of high salt and acid content really kills off any unwanted bacterial growth and thus allows for very long storage time, even at room temperature. However, a lot of vinegar will kill both good and bad bacteria and inhibit the fermentation process so the best option is to partially or completely omit the vinegar and instead keep the pickles in cool storage.
Note that vegetables pickled using a lot of vinegar are not fermented and thus contain no probiotics. If longer storage time is preferred, vinegar can be added once the fermentation process is complete.
There are some concerns about the relatively high salt content in brine fermented vinegars, although draining the brine and washing the vegetables before eating will reduce the sodium content. Salt quantity plays a role in how sweet/sour and crisp the vegetables will be and it is a lot of fun to experiment with different salt ratios.
Because of the long fermentation time many people are afraid of health hazards and that bad bacteria somehow will sneak their way into the food. I have come across recipes that claim it an absolute necessity to sterilise the jars and utensils and afterwards boil the full pickle jar to create a vacuum inside the jar. Anaerobic jars with air locks such as “Pickl-It”s have also had a surge in popularity. The argument is that mason jars are not completely air tight and therefore one cannot avoid contamination on some level. This is probably true, but from my experience brine pickling and any other food fermentation is safe as long as one has clean hands, clean vegetables, clean utensils and rinse the fermentation jar with very hot water before use. If the lid is properly sealed with rubber like a mason jar, the jar contains a minimal amount of oxygen and doesn’t have to be boiled to create an anaerobic environment nor should it need a special airlock device.
My thinking is that pickling has been done for a very long time and things were a lot less clean and “techie”  back then.
If you like your vegetables crunchy then brine fermentation is definitely the way to go. It takes a few weeks (4-6) for brined vegetables to ferment properly, so this is not the quick method for home pickling.

Kombucha SCOBYs

Kombucha SCOBYs


Kombucha is a fermented brew made from tea and sugar using a symbiotic 'colony' of bacteria and yeast (a so-called SCOBY) and an aerobic environment for it to interact with.
The SCOBY is a disc shaped “mushroom” (note that it is not an actual fungi) that is created when tea and sugared water are left to ferment. Bacteria and microorganisms present will feed on the ingredients and form a biofilm together. Two of these bacteria are unique to the brew: gluconacetobacter kombuchae, which feeds on the nitrogen in the tea to produce acids and build the SCOBY, and zygosaccharomyces kombuchaensis which is a yeast strain that produces alcohol, carbonation and helps build the SCOBY.
Microbial SCOBY cultures vary with the environment in which is it grown and thus the components of the final brew will also vary from place to place. Other variables include the longevity of the brewing process and organisms present in the water used.
There are some standard components left in every kombucha brew: acids such as acetic acid (vinegar), lactic acid, carbon dioxide, alcohol (under 0.5%), caffeine, bacteria, yeasts and some residual sugar.
The sugar content of kombucha is one of the many controversies in relation to the brew and on this topic as well as many other topics related to kombucha I have found a lot of contradicting research.
The scientific fact is that during the first fermentation stage the yeasts use the minerals from the tea to create enzymes that separate the sugar in the brew into fructose and glucose. After about one week of fermentation (the speed of the process is, as always, dependant on the temperature of the room) the sugars are still present in this state, but easier to digest. After about two weeks the SCOBY has begun to feed off the sugars and the sugar content is lowered while acid is created and the SCOBY is growing.
The longer the brew time, the less sweet and more acidic the brew. Some research claims that the sugar content is way too high for a brew claiming health benefits unless you brew the tea for a minimum of 30 days, other research claims that after approx two weeks of fermentation one is left with sugar content per litre equal to that in a piece of fruit.
Personally, I leave the kombucha for about two weeks, give or take. At this time the brew is slightly sweet and slightly acidic, just perfect for me. I use good quality unrefined rapadura or coconut sugar so if there is a little bit of sugar left in my brew, I don’t mind too much (if you are curious about sugars, see my post on it here). Besides, if there are no sugars left there is nothing for the yeast to “play with” during the second fermentation (bottling of the kombucha without the SCOBY and alternately with flavourings) and the drink won’t carbonate and get as fizzy as I would like.
Because of the variety of bacteria and yeasts present in the brew, kombucha boasts health benefits too numerous to list here. In essence, take the listing of health benefits I made on probiotics and add to it.
However, there is no “scientific proof” of the health benefits of kombucha and there have been done no clinical trials on the subject as far as I can see.
The proven facts on health benefits: in a number of studies on rats, kombucha decreased the negative effects of liver harming agents in the same way as paracetamol. The beneficial yeasts present in the brew will normally protect the body from harmful yeasts such as candida albicans. The drink also contains active enzymes.
More speculative claims are that kombucha can aid detoxification through its main bioactive saccharolactone, but this has never been “proven” due to the lack of testing on humans. Because tea is naturally antioxidant rich so is the kombucha, but research again differs on whether or not there is more or less antioxidants present after fermentation. Some research claims to prove a boost of B vitamins and amino acids as well as antioxidants in a finished brew.
Personally, I have a lot of faith in the health properties of kombucha – and it’s also delicious! It is a healthy way to get a pick-me-up which is not coffee, it is refreshing and one can add all kinds of health boosting herbs and spices.
Since I started brewing and drinking kombucha, my overall immune system has been better and so has my digestion. The drink has been brewed and used as medicine for hundreds of years and who am I to dismiss age old wisdom? I give kombucha to all my friends and I encourage them to brew their own. It’s fun, delicious and most likely really good for you.

Water kefir, kombucha and milk kefir fermenting in my kitchen

Water kefir, kombucha and milk kefir fermenting in my kitchen


Tibicos, perhaps better known as water kefir grains or sugar kefir grains, are a symbiotic culture of yeasts and bacteria just like a kombucha SCOBY, but because of the difference in bacteria and yeasts present the tibicos look and work differently from the kombucha SCOBY.
The grains, which are mostly composed of insoluble polysaccharides (complex sugars), are about 5 mm big, they are many and they feed off lemon slices, sugared water and the sugars in dried fruit. Similarly to the kombucha SCOBY kefir grains produce lactic and ascetic acids, alcohol and carbon dioxide by feeding off sugars and breaking them down into sucrose and fructose. The tibicos make the nutrients in the dried fruits more accessible and digestible and as with the vegetables used for brine pickling the dried fruits used to make water kefir get a vitamin boost. These vitamins are present in the finished brew.
Again similarly to a kombucha SCOBY there are no tibicos cultures that are exactly the same because the bacteria and yeast composition will vary with the environment. Water kefir grains also contain various alkaline minerals and need to be fed minerals to stay healthy. This is where the lemon and lemon peel comes in, as the peel is high in calcium. One can also use egg shells to give the drink a mineral boost.
Because of the vast variety of yeasts and bacteria present in the tibicos, their health properties are many and varied. Similarly to the health claims related to kombucha there is much scepticism surrounding the health benefits of water kefir.
Studies on the health benefits of kefir have from what I can find mostly been done with milk kefir and not water kefir and the health claims of milk kefir are well documented. As water kefir is an acidic brew one should be careful about having too much of it and as with all fermented foods the bacteria will not be suitable for everyone.
Water kefir is rich in probiotics from the fermentation process, vitamins from the fruit present, minerals, enzymes and supposedly also antioxidants and amino acids. As with kombucha there are disagreements about the remaining sugar content and whether or not it is healthy, however 48 hour old water kefir, if unflavoured, tends to be a more sour and thus less sugary drink than a two week old kombucha.
One can also use fruit juice or coconut water instead of sugared water to make water kefir and get a finished brew with less added sugar and a very interesting flavour. There is so much fun to be had experimenting with water kefir flavours!
Brewing water kefir at home can be a little bit risky as the fermentation and accompanying carbonation happens very quickly, especially if there is a rise in room temperature. This can make jars and bottles explode! After my first and very scary explosion I am now taking precautions by keeping the jars and bottles in a bag during the fermentation so that if they were to explode I won’t be at risk of getting a shard of glass in my eye.
Water kefir is a great option if you want to ferment something quickly as the process only takes 24-48 hours. It is a wonderful probiotic caffeine and dairy free drink alternative to kombucha and milk kefir.

Whey fermented kimchi and sauerkraut

Whey fermented kimchi and sauerkraut


Whey is one of the main proteins found in diary and it is very easy to extract at home from yoghurt, kefir or unpasteurised milk – many of the benefits of whey are destroyed by pasteurisation. It has a lactose content of about 5%, minerals, vitamins and milk proteins.
Whey also has a number of health benefits in addition to being probiotic! It contains all the essential amino acids with about 98 % bioavailability, it provides amino acid precursors to the antioxidant glutathione that among other things aids lymphocyte function, regulates other antioxidants and detoxifies at cellular level. Low glutathione levels have been linked to cancer, Alzheimer’s and Parkinson’s disease.
Whey contains lactoferrin which protects the body from viruses.
The quality of the whey varies with production and the best whey comes from goat’s or cow’s milk from animals that feed on lush, green grass grown on organic soil.
One does not necessarily have to ferment with whey in order to introduce it to one’s diet. A glass of whey mixed with water after a heavy meal will aid digestion and whey can also be used in smoothies, on porridge, in dressings etc.
Whey is rich in lactic acid and lactic acid-producing bacteria and when added to vegetables whey kick-starts the lactic-acid fermentation that would otherwise take weeks to begin in brine picking. Whey also lowers the PH in the jar so that it very quickly becomes uninhabitable for bad bacteria. Whey fermentation works best and most safely in an anaerobic environment.
One of the beautiful things about whey fermentation is that it is quick and incredibly versatile. You can ferment basically anything using only a little whey and 1-3 days of room temperature.
One can make for example berry drinks, sauerkraut, kimchi, beetroot kvass, ginger beer, turmeric tonic, chutneys, coconut yogurt, mayonnaise, ketchup and ferment any fruits and vegetables. Whey fermentation leaves the veggies with less crunch than brine picking does so some vegetables, like for instance cucumbers, are better pickled in salt than whey.
There are some arguments that milk bacteria only like milk and so whey should not be used for vegetables. Milk introduces external bacteria to the vegetables while salt pickling or just a completely anaerobic environment achieved by using airlock-jars only kickstart the fermentation process using bacteria already found on the vegetables.
These are facts that are impossible to disagree with, however personally I haven't experienced any problems after consuming a lot of whey fermented vegetables and drinks over the past year. The whey I use is made from raw milk that I buy from an organic farm with pasture fed cattle, so I get more bacterial diversity from my whey than one would get from making whey from commercially produced yoghurt or from buying a whey starter culture.
I for my part love the versatility of whey picking as the whey leaves the finished product with little flavour where salt could ruin it. It is also a very quick way to make impromptu probiotic foods.

There is a reason that fermented foods are, and have been for a very long time, present in diets all over the world and home fermentation is a fun and easy way to bring these foods into your diet.
Brine pickling is for the patient home fermenter, but if one has the time it is a brilliant way to utilise the soil’s bacteria to act on the vegetable. Use brine for making pickles with extra crunch and otherwise where salt would not compromise the flavour.
As long as the good kind of sugar is used, I say brew your kombucha for as short or long a while it needs for flavour. One can get used to the acidic flavour and leave it to brew longer after a while of drinking.
Water kefir is the most versatile and the quickest way to create flavourful probiotic drinks. The key to a healthier brew is to use good sugar, unsulfured organic fruit and remember to feed the tibicos minerals using slices of lemon or egg shells.
Despite the arguments against using milk bacteria to ferment vegetables I still love whey fermentation for its versatility and swiftness. Make sure to buy the best raw milk accessible to get the highest quality whey for your fermentation and your body.
Finally, a note on milk kefir: I am in the early stages of my exploration of this wonderful probiotic resource and as I don't consume much dairy it is a slow process. This post will be updated with milk kefir once I gain some more experience!

The health benefits of probiotic foods with live enzymes and amino acids are indisputable, but health claims aside, using fermentation to enhance flavours is a fun way to eat a less processed and more varied vegetable and fruit diet.
Kombucha and water kefir are healthier alternatives to any store bought soda pop and the options for playing with flavour combinations are seemingly endless. The “magic” of lactic acid fermentation is a creative way to get closer to your food and making your own pickles gives you the option to customise crunch and flavour to suit your own palette.


Thank you to Adrian Fisk who took most of the photographs for this post.