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Fun with Fermentation

What do beer, sauerkraut, sourdough bread, wine, yogurt, and pickles all have in common? They are all fermented! Fermentation is when a food or a substance is broken down into simpler components with bacteria and yeast being an essential factor. People ferment foods in following with family traditions, food preservation, improving the flavor of food, or for the potential health benefits. “Working so much in food safety, I often talk mainly about the bad, harmful bacteria, but fermentation is an example of using bacteria to our advantage. We wouldn’t have yogurt, cheese, chocolate, or coffee without fermentation and the helpful bacteria,” Lisa Peterson Nutrition and Wellness Educator with University of Illinois Extension explains. Additionally, fermented foods contain probiotics, good for gut health, and make nutrients more readily available and easily digestible.

There are two main types of fermentation, Lacto-fermentation, and alcohol fermentation. Lacto-fermentation is associated with fresh fruits and vegetables. All produce has the bacteria Lactobacillus. When fruits and vegetables are without oxygen, Lactobacillus turns the fruits and vegetables natural sugars into lactic acid, serving as a way to keep them longer acting as a preservative and preventing the growth of harmful bacteria. Have you ever taken a bite of sauerkraut and puckered? That sour taste is thanks to the Lactobacillus bacteria in action. Alcohol fermentation is the method used to make beer and wine.

Home fermentation has become increasingly popular recently, but humans have been doing it for over 12,000 years. When fermenting at home, the goals are to create an environment for bacteria to thrive, overpower the spoilage bacteria, and to increase the helpful microorganisms. The first step is making sure to wash fruits and vegetables, utensils, surfaces, containers, and hands before beginning. For fermentation, especially, you want to avoid introducing any type of harmful bacteria.

To create an environment for helpful bacteria to flourish, make sure to choose the right fermentation vessel. Food grade containers free of phthalate or bisphenol, high-density polyethylene containers, or high grade commercial stainless steel are suggested. Do not use copper, iron, lead-glazed, or galvanized metal containers for fermentation. Glass, wide mouth jars with plastic lids are another suggestion, but be sure to inspect for chips or cracks before using them. The general rule is a one-gallon container will hold five pounds of fresh produce. 

The best temperature for fermentation is between 68-72°F, and the process takes between three to four weeks in ideal conditions. If the temperature is too high, spoilage bacteria may take over and ruin the product as well as produce a less flavorful result. If the temperature is too low, the process may take six weeks or longer.

After fermentation is complete, store products in the refrigerator or a cool, dry place if it was safely canned. Shelf life for frozen and refrigerated fermented foods depends on the food and based on quality. For canned foods, most products canned properly are at best quality for up to one year.

University of Illinois Nutrition and Wellness Extension team is offering weekly webinars every Wednesday, June through July, from 1-2 pm on preserving garden produce. On Wednesday, June 17, the focus is on the art of fermentation and will go into more detail on controlling for spoilage, the role salt plays, water quality, and the use of weights and other equipment for fermentation. Call the extension office to sign up or register yourself at

Homemade Ginger Ale

1/8 tsp dry active yeast

1 cup sugar

2 tbsp grated fresh ginger root

3 tbsp freshly squeezed lemon juice

Spring or filtered water

2-liter plastic soda bottle

1. Put the sugar and yeast into the soda bottle and gently shake to distribute. Peel and grate the ginger. Measure 2 tbsp into your measuring cup.

2. Juice the lemon and measure 3 tbsp into the same measuring cup. Fill the measuring cup with ½ cup water and stir. Using a funnel, pour the contents of the measuring cup into the soda bottle. If the ginger gets stuck, use more water to wash it through.

3. Fill the bottle the rest of the way up with water and screw the lid on. VERY GENTLY, tip the bottle upside down until the contents are thoroughly mixed. Let the ginger ale sit for 24-48 hours on your counter at room temperature until the bottle can no longer be squeezed. It should be hard to the touch. The time it needs to sit will depend on the temperature inside your house. The warmer it is, the shorter the amount of time it will take.

4. Move the ginger ale to the refrigerator and let sit for 24 hours before opening to avoid an overflow.

NOTE: This is a fermented product and if it sits too long without being “burped” of the carbon dioxide, it will explode. Never make this in a glass container.


Questions about food safety, nutrition, food preservation, or looking for recipes? Contact the local University of Illinois Extension office.

Source: Lisa Peterson, Extension Educator, Nutrition and Wellness