Lacto fermentation is a natural, biological, and amazing process involving beneficial microorganisms. The bacteria change the make-up of food products creating lactic acid which makes food more acidic. Bacteria also increase the nutritional value of fermented food.
When food is fermented it becomes easier for the body to assimilate vitamins, enzymes, and other nutrients because they are already “chewed and digested” by beneficial microorganisms.
Food processed by beneficial microorganisms is highly bioavailable and helps keep the digestive tract in balance.
Lacto fermentation describes a process in which microorganisms convert sugars in vegetables and milk into lactic acid and other beneficial compounds.
The more lactic acid present in fermented food, the more tangy and refreshing it tastes.
Lacto fermentation is amazing!
- It prevents growth of harmful microorganisms;
- promotes growth of beneficial bacteria;
- increases bioavailability of nutrients;
- helps control intestinal infections;
- acts as a natural preservative;
- makes food easier to digest.
Three simple principles
These simple principles apply to vegetables fermented at home. You will succeed if you stick to these principles.
What problems can occur when fermenting vegetables?
Unwanted microorganisms can disturb fermentation by producing butyric acid and other bad-smelling substances. Because of this, the final product may develop a bad taste and soft texture. This has happened to me a number of times so I’ve learned much from my own mistakes.
Basic requirements for a successful fermentation:
- Correct salt concentration
- Correct temperature
- Absence of oxygen
1. Salt concentration
Between 1-3% of salt is viewed as a good range. I use Himalayan or sea salt in all my recipes. Celtic sea salt is also good.
Lactic acid producing bacteria (probiotics) often tolerate high salt concentrations. Traditionally, much salt was used to promote fermentation and prevent the growth of non-desirable organisms.
Many starter cultures work better when salt is added.
For example, Leuconostoc bacteria initiates fermentation both in kefir and sauerkraut. It has a high salt tolerance and is not disturbed if more salt is added.
Try adding the excellent fresh celery juice as brine. It has properties that help preserve the vegetables. However, the final product will not taste celery, you hardly feel it at all. Cabbage juice is also fine. But you need a juicer.
Traditional (wild) fermentation without a starter
Wild fermentation is still used in many places and it works well if you know what you’re doing, though it can be a bit more risky. How does is work?
Vegetables are placed in a layer of about 2.5 cm (one inch) depth in the fermenting container. Plenty of salt is sprinkled over the vegetables. Then the next layer of vegetables and salt. This is repeated until the container is three-quarters full. A cloth (or lid) is placed on top. Sometimes a weight i used to compress the vegetables, keep them submerged, and to support the formation of a brine which takes about 24 hours. As soon as the brine is formed, fermentation starts and bubbles of carbon dioxide start to appear. It’s fermented for7-15 days, then stored in a cool place.
Generally, lactic acid producing bacteria work best at temperatures of 64 to 72 degrees (18 to 22ºC) when fermenting vegetables. Most problems occur when it’s too warm.
Some general facts to consider:
- Probiotic bacteria prefer 68 to 86 degrees (20 to 30ºC). Above 72 degrees (22ºC) favors lactobacillus species. (fermented vegetables, sauerkraut, fermented dairy)
- Some bacteria as thermophiles (in yogurt) prefer 120 – 130 degrees (45-5OºC, close to a radiator)
- Other bacteria like it cooler, as Leuconostoc species. They have an optimum of 64 to 72 degrees (18 to 22ºC)
Too warm during fermentation promotes mold and unwanted bacteria. But using a starter culture helps controlling the batch.
Lacto-fermentation at home works best in the absence of oxygen. Using air-tight jars is therefore important.
During the first days of fermentation, pressure builds in the jars. So don’t screw the lids on too tight, or open the lid for a second to let the gas out. After fermentation, lids should be screwed on tighter to keep air out.
Three phases of lacto-fermentation
It involves “breaking down” vegetables and lasts only a few days. You might see bubbles and brine coming out of the jars. During this phase, most harmful microorganisms are destroyed as the batch turns increasingly sour.
Good bacteria are in complete control of the jar and consume sugars contained in the vegetables. Lactose, glucose, fructose, and sucrose are all converted by the bacteria into lactic acid and other substances. This gradually increases the bio-availability of nutrients.
The level of acidity increases slowly in the brine creating the familiar tart, tangy flavor in fermented food. The acidity preserves the vegetables since most harmful bacteria don’t survive in such an environment. The more lactic acid is produced, the more acidic the flavor.
Storing the jars in a cool place slows down fermentation. However, the beneficial microorganisms are still alive, slowly consuming carbohydrates and producing a range of potent substances. The bacteria can stay alive in the jars for many months. The longer the jars are stored, the more tart and complex aromas are created.
Using starter cultures
Several microorganism species are involved in the natural or wild lacto- fermentation process. These naturally occur on raw vegetables and in raw milk.
The bacteria in a starter culture will quickly take control together with the ones naturally present on the veggies. Bacteria in the starter culture will dominate the process from start to end.
- More lactic acid
- Fewer problems
- Predictable result
- Stable fermentation
- Easier fermentation
- Can be consumed faster
- More beneficial bacteria
In addition to desirable bacteria, there are also undesirable micro-organisms present on vegetables which can interfere with the fermentation if allowed to multiply unchecked.
The quality of the final product depends largely on how well the undesirable organisms are controlled. Some bad bacteria use protein as an energy source, thereby producing unpleasant odors and flavors.
What bacteria are involved when fermenting at home?
Here are a few examples of microorganisms involved in lacto fermentation of different ingredients.
Yogurt: Fermenting milk into yogurt involves Lactobacillus bulgaricus, Lactobacillus acidophilus, and Streptococcus thermophilus.
Kefir: Produced with cow, sheep, goat milk or even soy, rice or coconut milk. Originates in the Caucasus region. Kefir contains strains of Lactobacillus Caucasus, Leuconostoc, Acetobacter species, and Streptococcus species. Beneficial yeast is also involved.
Sauerkraut: Fermented cabbage. Strains of Leuconostoc are involved as well as Pediococcus and Lactobacillus strains like Cucumeris. Lactic acid bacteria are the primary group of organisms involved in sauerkraut fermentation.
- Leuconostoc mesenteroides – acid and gas producing
- Lactobacillus plantarum – produces acid and a little gas
- Lactobacillus pentoaceticus – acid and gas producing
Miso: Japanese ways of fermenting rice, barley and mostly soybeans. Miso is a natural food containing healthy microorganisms such as Tetragenococcus halophilus. Probiotics bacteria is killed by over-cooking so add miso just before serving.
Natto: Soybeans fermented with Bacillus subtilis. It contains enzymes and compounds with exceptional health benefits.
Kimchi: Often made from cabbage, radish, cucumber and other vegetables and seasonings like ginger, garlic, scallions and many other. It contains a number of bacteria, especially Lactobacillus kimchii.
Kombucha: A kombucha culture often contains Gluconacetobacter xylinus and one or more of the yeasts Saccharomyces cerevisiae, Brettanomyces bruxellensis, Candida stellata, Schizosaccharomyces pombe, Torulaspora delbrueckii, and Zygosaccharomyces bailii.
Lacto fermentation in all forms is an amazing process. Be sure to consume plenty of it!