Fermenting Vegetables
What is fermentation anyway?
Fermentation is a metabolic process in which an organism converts a carbohydrate, such as starch or sugar, into an alcohol or an acid in the absence of oxygen. For example, yeast perform fermentation to obtain energy by converting sugar into alcohol. Bacteria perform fermentation, converting carbohydrates into lactic acid.
There are two types of fermentation:
Lactic Acid Fermentation - bacteria convert carbohydrates into lactic acid. Think: Sauerkraut, Olives, Pickles
Alcohol Fermentation - yeast converts carbohydrates into alcohol. Think: Bread, Beer, Wine, Hard Cider, Vinegar
Wild v. Cultured
Wild fermentation utilizes the yeasts and bacterias naturally present in an environment or on the surface of a fruit or vegetable by creating an environment when they can thrive. This creates a diverse and variable ferment.
A cultured ferment is created by adding a particular combination of yeasts and/or bacterias to make a controlled and predictable ferment. By saving the cultures from a previous batch we can perpetuate that specific culture. You can save the cultures from your own wild ferments, or you can acquire centuries-old cultures for prized ferments like San Francisco sourdough, bleu cheese, kombucha.
Equipment
Crock or Jar: Ferments are best made in ceramic or glass. Never ferment in metal! Metal containers can leach into your ferments as they sit for extended periods of time becoming more and more acidic. Food-grade plastic can also be used.
Weight: The most important step in preventing spoilage in your ferments is making sure solids remain submerged in liquid. A weight can be an object that will sit inside your fermenting container and keep the solids submerged. Some options include a jar filled with water, a plate with a clean rock on top, and specially designed fermenting weights. You may also want to place large leaves (like those from the outside of a cabbage) under the weight to cover any surface area your weight cannot.
Cloth Covering or Airlock: A piece of muslin with a rubber band, a pillowcase, etc. can be used to prevent bugs and other detritus from contaminating your ferments. While not strictly necessary, many people prefer to cap their vegetable ferments with an airlock to prevent microbial contamination. An airlock can be helpful in reducing mold growth.