Starter cultures are recommended by many as a superior way to prepare fermented food. However, for centuries people in many cultures have prepared fermented vegetables, sauerkraut, kefir and many other foods without the use of starter cultures. Therefore, the question is
I’ve fermented vegetables both with and without a starter culture and can both work well. However, a high-quality starter culture yields superior results. Why is this so?
This article will focus on three questions:
- Is there a difference between wild fermentation and using starter cultures?
- Are there any advantages of starter cultures?
- What starter cultures are best?
Starter cultures vs wild fermentation
Spontaneous fermentation refers to the process of letting natural bacteria already present on vegetables or in the milk to start the fermentation process. Therefore, no microorganisms are added for this process to happen. However, the right environment needs to be created to promote bacterial growth. This might involve shredding vegetables, adding salt, using airlocks, or keeping the right temperature.
Microorganisms are present in most vegetables and raw, unpasteurized milk or cream. Cabbage, carrots, celery and many other vegetables can have up to 40 different bacteria species naturally occurring. Some bacteria species will, under the right circumstances, start consuming sugars present in vegetables and dairy. This process produces other substances including lactic acid. Lactic acid is responsible for the familiar tart, tangy flavor of fermented foods.
As stated, for centuries, people used spontaneous or wild fermentation to ferment dairy, cabbage, beer, and wine. I’ve fermented vegetables this way many times and it has worked well. However, wild fermentation is by nature unpredictable and it can result in uneven quality. I’ve sometimes prepared a delicious batch of spontaneously fermented veggies, only to fail with the next batch, even though I did not change the recipe. But that’s the nature of wild fermentation.
Destabilizing factors in spontaneous fermentation
- Natural microorganisms: Wild fermentation means that whatever bacteria and yeast you have on the vegetables will be the ones controlling the fermentation process. There are many different species that naturally are present vegetables. Therefore, the result will depend on what species will dominate fermentation. Aggressive farming and use of pesticides ruins the soil and disturbs the delicate balance between microorganisms naturally inhabiting vegetables.
- Salt: In the case of sauerkraut and fermented vegetables, the salt concentration affects the growth pattern of different bacteria species. Too much salt will prevent the growth of some bacteria but promote other species to grow. And too little salt may allow unwanted bacteria to take control. For example, a salt concentration of 2.0 to 2.5% is often recommended because the lactobacilli strains are slightly inhibited, but the cocci bacteria that are needed to initiate the fermentation process will not be affected. Sometimes the same salt concentration can disturb desirable organisms more than the undesirable since some unwanted organisms can tolerate salt concentrations up to between 5 and 7%. However, it should be noted that what keeps the bad bacteria at bay is not only the salt but mainly the acidic environment created by the lactobacilli species.
- Temperature: Changes in temperature can affect which bacteria species will grow faster and dominate the batch. In spontaneous fermentation the sequence in which different bacteria species grow is essential. Even a few degrees more or less can change the activity of the microbial process and affect the quality. Therefore, you must control the temperature to succeed.
Sauerkraut—an example of wild fermentation
Three major steps in the (wild) sauerkraut process
Step One: The first microorganisms to start up fermentation are the gas-producing cocci L. Mesenteroides. This happens after 24-48 hours when you see bubbles in the jars. These microbes produce lactic acid and when the acidity level reaches 0.25 to 0.3%, the cocci bacteria slow down and begin to die off, although their enzymes continue to function.
Step Two: Now the fermentation work is continued by the lactobacilli (L. plantarum and L. Cucumeris). These strains continue the process until an acidity level of 1.5 to 2% is attained. A high salt concentration and low temperature can inhibit these bacteria to some extent. But a lower salt concentration will promote their growth.
Step Three: Finally, L. pentoaceticus continues fermentation, bringing the acidity levels to 2 to 2.5% thus completing the fermentation process. Now around 7-15 days has passed and the sauerkraut is ready for consumption. Stored in a cool place, it will last for many months.
As seen here, spontaneous fermentation is a delicate process involving factors that are difficult to control completely. Spontaneous fermentation has its beauty as you’re dealing with natural, live bacteria. The interrelationship and cooperation between the different bacteria species are truly fascinating.
Conclusion: Naturally fermented vegetables can have excellent quality and superb taste. However, you might also fail from time to time, even if conditions seem ideal. Sometimes the final product will be OK to eat but not perhaps as delicious or crunchy as you would like. Again, this is because spontaneous fermentation is by nature more unpredictable. You also need mor patience since the process takes longer than if using starter cultures.
Starter cultures—what are they
Starter cultures have been used for a long time to improve the quality of fermented foods. After Louis Pasteur discovered that microorganisms are responsible for the fermentation process, starter cultures were developed around 1892 for the dairy industry. Today starter cultures are used for fermented vegetables, sauerkraut, yogurt, kefir, beer, and many other foods.
Starter cultures definition: A preparation of beneficial microorganisms, whose activity has the desired effect in the food being fermented. Starter cultures initiate the fermentation process and quickly takes control. The precise composition of the starter culture will determine how it affects the food being fermented.
Starter cultures can be a pure culture from a commercial laboratory. You can also use part of an earlier batch of fermented food. Starter cultures can be very similar to probiotic supplements.
Definition of probiotics: A live microbial food supplement which beneficially affects the host by improving the intestinal microbial balance. A broader definition: living microorganisms, which upon ingestion in certain numbers exert health effects beyond inherent basic nutrition.
Even though their recommended usage differs, starter cultures and probiotic supplement are very similar. Both starter cultures and probiotic supplements usually contain between 1-14 bacteria strains.
The microorganisms in starter cultures are carefully selected. Many bacteria produce lactic acid which prevents spoilage. Other organisms produce metabolites that give desirable flavors, or produce enzymes that mature a dairy product like cheese. Therefore, starter cultures are composed to produce different flavors and texture depending on how they will be used.
Composing a starter culture
Each bacteria species have unique properties and perform specific tasks in your gut. High-quality starter cultures and probiotic supplements combine different bacteria species in a way that enhances the total effect many times. Bacteria can be combined to combat or prevent certain health problems.
Examples how bacteria can be combined to enhance health effects:
- Research reveals that some infections in the lining of the intestine caused by bacteria (necrotizing enterocolitis) can be prevented if you use the bifido strain in combination with Lactobacillus acidophilus.
- Studies also show that you can prevent diarrhea in infants (rotaviral diarrhea) much more effective when bifido is used with another bacterium called Streptococcus thermophilus.
- Research suggests that taking a specific combination containing bifidobacteria, lactobacillus, and streptococcus might help control symptoms of ulcerative colitis and even prevent their recurrence.
High-quality starter cultures are prepared in a way that combines different microorganisms that work in synergy to promote fermentation and has the potential to treat or prevent certain health problems.
Research confirms effectiveness of starter cultures
Research confirms that starter cultures are often far superior then allowing for spontaneous fermentation.
The Journal of the Science of Food and Agriculture reported in October 2013 about using only one probiotic bacteria strain Lactobacillus plantarum IMDO 788 as a starter culture to control vegetable fermentations. Researchers found that the using Lactobacillus plantarum as a starter culture strain for cauliflower and mixed vegetable fermentations resulted in an accelerated fermentation process. The starter culture bacteria quickly took control dominated the fermentation process producing lactic acid, ethanol, and other substances. This confirms that a starter culture stabilizes the fermentation process as the probiotic bacteria take full control over the process, making fermentation much more predictable and stable.
The Journal of Microbiology and Biotechnology: The lactic acid bacterium Streptococcus thermophilus is widely used as a starter culture for the production of dairy products like yogurt. Researchers discovered that this specific bacterium has the ability to metabolize 17 different kinds of sugars. The probiotic bacteria transform sugars into several other substances as lactic acid and exopolysaccharides (EPSs). The EPSs give yogurt a thicker body and texture. In addition, EPSs has been found to have antitumor, antiulcer, immunomodulating, and cholesterol-lowering properties. This study supports the potential benefits of using this probiotic strain as starter cultures.
Department of Food Technology, Victoria University of Technology, Australia: Researchers assessed the viability of yogurt and probiotic bacteria from commercial starter cultures. They found that that the number of probiotic organisms and the viability of these organisms in yogurt were dependent on the interaction of several probiotic strains. This indicates that multi-strain starter cultures are to prefer since the different bacteria strains support one another.
Starter culture advantages
There’s a summary of starter culture advantages over wild fermentation.
- Promote a stable and predictable fermentation, even if you don’t have perfect conditions
- Reduced risks of unwanted mold, yeast, and other bad microorganisms
- Higher levels of the very potent exopolysaccharides (EPSs)
- Higher levels of lactic acid, diacetyl, acetate and ketones
- Contribute to a crunchier texture and more complex taste
- Higher levels of natural hydrogen peroxide (H202)
- Help preserve the product longer
- Ensuring constant high quality
- Higher levels of vitamin K2
- Fermentation is faster
Best starter cultures
Which starter culture is best depends on what you want to ferment and under what conditions? It is good to try a few different starter cultures to see which produces a product that you enjoy. The starter cultures recommend here are well-researched and will work well in most instances.
This is a favorite which I’ve used many times. It has a nice combination of probiotic bacteria producing delicious vegetables. It costs around $24-27 and is very easy to use. Check my post on fermenting vegetables where I use this brand. Cultured Vegetable Starter contains the following beneficial bacteria:
- Lactobacillus plantarum
- Lactococcus lactis ssp. lactis
- Lactococcus lactis ssp. cremoris
- Lactococcus lactis ssp. diacetylactis
- Leuconostoc mesenteroides ssp. cremoris
- Lactobacillus kefyr
A great starter culture containing many potent bacteria strains and produces very high quality fermented vegetables. I’ve recently tested this starter and the result was excellent!
Kefir Starter Culture Body Ecology
Kefir is very similar to yogurt, it just contains different and often more bacteria strains. I used to drink lots of kefir because of stomach problems. Many people love the Body Ecology Kefir Culture Starter; it contains seven beneficial bacteria.
However, some people have had problems with transferring an earlier batch to a new batch. After two or three batches the culture was out of balance and became very tangy and sharp. This can happen when the delicate balance of the bacteria is lost. Most often this is because of using too much of the old batch or keeping the batch too long at room temperature.
Body Ecology allows you to create up to seven batches from one package; this will work well provided you do it correctly. Check my post on preparing Kefir at home.
Body Ecology Kefir Starter in one of the best on the market; it contains the following seven beneficial bacteria:
- Lactococcus lactis subsp. lactis
- Lactococcus lactis subsp. cremoris
- Lactococcus lactis subsp. diacetylactis,
- Leuconostoc mesenteroides subsp. cremoris
- Lactobacillus kefyr (thermophilic)
- Saccaromyces unisporus
- Kluyveromyces marxianus
These are great, cheap and organic kefir grains. They do not contain as many bacteria as Body Ecology, but they are easy to use and many love them. The grains contain bacteria and yeast working in symbiosis and create great kefir in about 18 hours.
I like it best using whole milk. The kefir becomes creamier when using milk containing more fat. I mainly use raw milk with 4.3% fat and I just love the taste.
Making kefir is really simple. Just follow the basic instruction and you’ll be fine. If you want to enjoy kefir on a daily basis, then every 2 days or so you spend 5-10 minutes straining and pouring the milk on the same grains that can be used for a long time.
Children love kefir, especially if you mix it with some natural sweetener like honey. And as the kefir grains are reusable, it is an easy and inexpensive way to make kefir forever! Kefir grains is the perfect starter culture if you’re just starting out making your own fermented foods, and for families with little time to spend in the kitchen.