Lactofermentation, also called lactic acid fermentation, is driven by lactic acid bacteria that transform sugars into lactic acid. Although these microbes were initially discovered in milk—hence the name Lactobacillus—they are not limited to dairy. In fact, they are ubiquitous in the environment.
Unlike ethanol fermentation that produces alcohol, lactic acid fermentation is used to create many foods: fermented vegetables such as sauerkraut and beet kvass, and cultured dairy like yogurt and kefir. These bacteria consume the natural carbohydrates in cucumbers, transforming them into tangy pickles.
A common misconception among fermentation beginners is that dairy products like whey are necessary to initiate lactofermentation of vegetables such as sauerkraut. This idea was spread by the influential book Nourishing Traditions, which included whey in every fermented vegetable recipe.
Because lactic acid bacteria are naturally present on our skin, on produce, and on kitchen surfaces, there is no need to add a starter culture. Vegetables will ferment safely and effectively on their own, often yielding superior flavor.
The Majority of Fermented Vegetables Require No Starter
Nearly every fermented vegetable recipe—from homemade sauerkraut to sour pickles—neither requires nor significantly benefits from a starter culture. Traditionally, they are made without one. The process is straightforward: salt the vegetables, pack them into a crock or jar fitted with an airlock, and let the native bacteria slowly work, creating a pleasantly sour flavor and preserving the vegetables for extended periods.
This traditional method—fermenting without a starter like whey—is called wild fermentation, a concept popularized by Sandor Katz in his book Wild Fermentation. It relies on naturally occurring bacterial strains rather than the domesticated ones found in starter cultures.
Vegetables and Other Foods That Do Not Require a Starter
- All fermented vegetables: sauerkraut, sour pickles, sauerruben, kimchi, and similar.
- Preserved citrus fruits like lemons and limes.
- Bonny clabber (clabbered raw milk).
Certain Fermented Foods Absolutely Require a Starter
A few fermented products need a starter culture to guarantee safety, consistency in taste and texture, or both.
Sourdough bread relies on a starter—either created through wild fermentation or, more reliably, obtained from another baker. Kombucha and Jun tea require a SCOBY (mother culture) for proper brewing. Water kefir needs water kefir grains, while yogurt and milk kefir each depend on their respective starter cultures. Most homemade sodas, such as root beer or probiotic lemonade, also require a starter.
If sweetened black tea—the base for kombucha—is simply left on the counter, it is prone to mold and will not become sour naturally. But when a kombucha SCOBY is introduced, the bacteria and yeast consume the sugar, producing acids that create a tangy flavor and enriching the tea with B vitamins.
Likewise, raw milk left at room temperature will naturally sour and clabber into bonny clabber, but the flavor and texture can vary significantly. Using a yogurt starter culture ensures consistent results every time—whether you desire the thick, ropy consistency of viili yogurt or the sweet-tart profile of Bulgarian yogurt.
Foods That Mandate a Starter Culture
Some Fermented Foods Are Enhanced by a Starter but Can Be Made Without
Certain fermented items can be made via wild fermentation without a starter, yet they often turn out better with one. These are usually short-term ferments like condiments or high-sugar fruits. Adding a starter culture jump-starts the fermentation, yielding more predictable outcomes.
Homemade fermented condiments such as ketchup and mustard develop peak flavor within just a few days. Because they are pastes, keeping them submerged in brine is challenging, leaving them exposed to oxygen and vulnerable to mold. Inoculating with a starter culture shortens the fermentation period, thereby lowering the risk of mold (proper equipment also aids in prevention).
High-sugar fruits tend to become alcoholic if fermented for too long. If your goal is a light sauce, condiment, chutney, or relish rather than an alcoholic beverage, using a starter culture to shorten the fermentation time can produce a vibrant, bacteria-rich result without alcohol. Try this recipe for fermented mixed berries.
Certain ferments like beet kvass are traditionally made with a starter culture even though they can be wild-fermented. Personally, I prefer to follow tradition and include a starter.
Foods That Are Improved by a Starter but Not Dependent on It
- Condiments and pastes that are hard to keep submerged in brine.
- Fruits with high sugar content.
Selecting the Right Starter Culture
Because Nourishing Traditions recommended whey in every fermented recipe, many beginners gravitate toward whey obtained from homemade yogurt or clabbered raw milk. Whey is cheap and plentiful if you already make yogurt or have raw milk. However, any liquid teeming with beneficial bacteria works, as does a commercial starter culture.
If you are using fermented foods for therapeutic purposes and want a particular bacterial strain, selecting a starter culture that contains that strain can be advantageous.
Options for Starter Cultures
- Whey from straining yogurt, kefir, or clabbered raw milk (note: sweet whey, powdered whey, and cheese whey are ineffective)
- Brine from fermented vegetables, e.g., sauerkraut juice or pickle brine
- Kombucha or Jun tea
- Water kefir
- A high-quality probiotic supplement
- A commercial starter culture from a reputable source
Handy Fermentation References
Wild Fermentation and The Art of Fermentation are two outstanding books on traditional fermentation techniques that deserve a place in your library.
Keep in mind that fermented vegetables don't require a starter, but using proper equipment—such as a fermentation crock or a jar with an airlock—will improve your outcomes.
For items that do need a starter, purchase them online from trusted suppliers. Kombucha and Jun SCOBYs, along with fresh water kefir and milk kefir grains, are available here. Yogurt cultures and sourdough starters can be found here.
Commercial starter cultures are a solid option for foods that benefit from their addition.
