Fermenting

Fermentation of food and beverages has been around for centuries as a safe way to preserve food. Fermenting is the process by which beneficial bacteria break down food under conditions that improve the test, texture, and shelf life of the food or beverage. It is important to maintain a high level of cleanliness before and during the process, follow research-tested procedures, and ferment under ideal conditions to obtain the safest, best quality product.  

The process of fermentation takes between three to four weeks to complete under ideal conditions. Store the container at 70°–75°F (21°–23°C) while fermenting. At these temperatures, sauerkraut for example will be fully fermented in about three to four weeks; at 60°–65°F (15°–18°C), fermentation may take six weeks. Below 60°F (15°C), sauerkraut may not ferment. Above 80°F (26°C), sauerkraut may become soft and spoiled. 

After fermentation is complete, store products in the refrigerator; store products in a cool, dry place if they have been safely canned. Shelf life for frozen and refrigerated fermented foods depends on the food and based on quality. For canned foods, most properly home-canned products are of the best quality for up to one year. 

As with all low-acid vegetables, do the following when cucumbers are made into fermented dill pickles:

• Do not alter vinegar, food, or water proportions in a recipe or use vinegar with unknown acidity. Use vinegar with 5% acidity.

• Use only recipes with tested proportions of ingredients. 

• There must be a minimum, uniform level of acid throughout the mixed product to prevent the growth of botulinum bacteria.

USDA has two research-tested recipes for fermented foods – dill pickles and sauerkraut, which are included in the sources below.
 

Sources: 

National Center for Home Food Preservation – Fermenting
Background information and recipes for fermented dill pickles and sauerkraut