Fermentation is a funny thing; it kind of just happens. But most of us do what we can to control it. We add salt to our vegetables to keep them crisp and preserve them longer. We add specific cultures to our milk to manipulate the flavor of the end product. And we go out of our way to make it work for us.
But fermented foods as we know them, for the most part, were discovered often times by accident. And it is those accidents that we now cherish and add to our meals. But our ancestors most likely considered the best parts of these foods to not be the delicious flavors they add, but the preservation qualities of the fermented foods themselves.
This form of food preservation has been going on for generations, and for good reason. Before canning and freezing and the modern day appliances that made all of that possible, fermentation could preserve food with very little added energy or special ingredients. And that is precisely what makes it a more sustainable means of food preservation today.
Here’s what I mean.
Each of the main categories of cultured foods boasts better keeping qualities than its modern or fresh counterparts. For that reason these cultured foods can be considered “preserved”. One of the key components of this is the lactic acid, and other organic acids, created during the fermentation process.
Fermented pickles and preserves boast lactic acid, which acts much like vinegar, or acetic acid, in preserving the vegetable. The acidic nature of the brine surrounding the vegetable fights off harmful bacteria, thereby preventing spoilage. If properly prepared and kept, these can keep for literally months or years.
Yogurt, buttermilk, and kefir all contain beneficial organic acids that create an environment unfriendly to putrefying bacteria. There are also beneficial yeasts and bacteria involved that help to crowd out the unfriendly versions of both microorganisms. These products will keep longer than fresh milk without spoiling, though they do have a shelf life of their own. Cheese is, of course, the ultimate form of dairy preservation.
I have heard from some bakers who are certain that their sourdough bread is still “alive” even after baking. I can’t speak to that either way, but I do know that sourdough bread tends to keep longer, without molding and without staling, than those breads made with quick-rising yeasts. For that reason, bread can be baked less frequently and be made to stretch longer throughout the week from fresh loaf to casserole ingredient to bread crumbs.
Soy & Beans
This is a great example of restraining the natural progression of microorganisms in favor of a better end product. As they ferment, beans can really give off an odor, and peculiar flavor. By harnessing this process by adding specific cultures or controlling the environment, foods like tempeh, bean pastes, and soy sauce become delicious additions to our table.
And all of these processes can be done with little to no energy output. Which is why it plays an important role as a method of food preservation in a sustainable food system.