The term “fermented foods” applies to many different kinds of foods, which can be loosely classed in several different categories.
This can help you know which type of fermentation process works best, and what kind of environment is appropriate for the food you want to ferment.
Fermentation does two things: It encourages the growth of certain microbes – bacteria or yeasts (that means FUNGUS, or even MOLD – not all mold is harmful). Those microbes then CHANGE the food – imparting a different flavor, incorporating air bubbles, adding alcohol, extending shelf life, or other changes that people want to impart to their food.
So, we have foods that do really well in an open container, some that do well in open or closed container (they aren’t picky as long as conditions inside the ferment are right), and some that are easier to ferment in an airlock system (because they do best in a closed container, but they release a lot of gas, and an airlock system vents more easily). NONE of them require an airtight environment.
Some of the basic classes of fermented foods include:
- Brine pickled foods – this includes pickled vegetables of all kinds, pickled salsa, and sauer kraut. These foods either use a salt and water brine to submerge the food, or by adding salt to the food, they create their own salt brine to cover the food. These are some of the easiest foods to ferment. They work well in either type of fermenting system as long as you keep the food under the brine.
- More solid salted fermented foods – bean paste, hummus, mustard, ketchup, mayo, and other foods which are fermented but do not have a brine on them. These do best in an enclosed system, though you need to leave plenty of headspace, they can expand quite a bit! Many people do these successfully in a mason jar, by venting the lid periodically to keep gasses from building up.
- Cultured Fermented Dairy – Kefir and yogurt, sour cream, and other milk cultures which are cultured using a specific bacteria or bacteria and yeast starter, and which are grown to encourage the growth of those specific microbes in the milk. These can work well in either type of system, though a closed (but not airtight) system is traditional. Kefir will gas quite a bit.
- Sourdough – Either wild or cultured sourdough starter. This can go either way also, and partly depends upon the stage the starter is in. To begin with, some starters work best in an open fermenting environment. If reviving a dried starter given to you by someone else though, you may wish to do it in a closed airlock environment, to discourage outside contamination (this is actually NOT a huge issue from the air unless you live in a very moldy environment, most outside contamination comes from ingredients, or improperly cleaned dishes, not from the air).
- Alcoholic Beverages – Modern brewing is done with an airlock – Traditionally done in open vats, or in a cask with a hole at the top which let out the gasses and much of the foam as the brew expanded. After the initial fermentation, it is sealed up in containers for long term aging, or in the case of ale, used right away. The goal here is to concentrate the alcohol and keep out airborne microbes that would cause it to turn to vinegar. Alcohol is usually cultured with specific microbial cultures to produce a more predictable flavor, but was traditionally done without that. There is NO direct comparison in needs between alcoholic beverages and pickled vegetables, because one has a high amount of natural sugars, and the other is fermented in a salt brine. Those two internal environments are completely different. We do not provide information on creating alcoholic beverages nor do we encourage their manufacture.
- Water Kefir – This stuff will brew open or closed. If you want a low alcohol concentration, drain off the grains, and re-ferment the water for several days, in an open or loosely lidded container. This diminishes the alcohol content and gives it a vinegary flavor and smell. If you keep it in a closed container, it WILL become alcoholic. “Tests” which purport to show otherwise were improperly conducted, invalidating the results. It becomes most alcoholic when combined with fruit juice (you just made wine, folks!).
- Kombucha, and Vinegar – both of these ferment best in an open fermenting container, until established. Vinegar, once it is finished fermenting, is stored in an airtight container. Kombucha is fermented in an open container until the Scoby is established, after which it can be fermented in an airlock. Kombucha is another thing which we do not ferment ourselves, nor do we provide further information on doing so (it is mentioned here because of the number of requests we get regarding which type of cap to use).
The type of environment a fermented food requires depends upon the needs of the food during fermentation, and upon the end goal.
Once you can do one food from a fermenting group, you can easily do another from the same group. Even between all of the groups, a similar set of skills and conditions are required for the majority of the tasks involved, so it is not difficult to learn to make pickles if you have made kefir, etc.
The whole argument over whether you have to have an airlock system to properly ferment foods or not is pretty silly really. Some things REQUIRE open air, some do better in a closed system, but none of them require an airlock. It is just a matter of convenience for those things which do better in a closed system but which gas a lot during the fermentation process. It helps to not have to keep venting the jar.
Frankly folks, we’d love to sell you our airlock cap. But we’d much rather give you the facts and retain our integrity than to leave out half of the truth in an attempt to persuade you to buy our product. If you want convenience, good tools can help make the process easier and a bit more predictable. But if you just need to get good food onto your table, just DO it, and don’t feel guilty because someone is trying to persuade you that you have to spend a boodle to do it right! You don’t. Just follow the longstanding rules that humanity has practiced for thousands of years, and you’ll be able to turn out healthy and invigorating foods that you and your family can enjoy for months.
Happy pickling!