What is fermentation?
There are many ways to ferment foods. Fermenting vegetables in salt is probably the simplest and most cost effective way to preserve produce for new fermenters. All fresh vegetables naturally contain microorganisms like bacteria, yeasts and moulds. Some of these microorganisms will spoil vegetables, but certain bacteria are beneficial and under the right conditions can transform raw foods into something really special. The beneficial bacteria break down the natural sugars in the vegetable into forms that are easier to digest. Lactic acid is a by-product of fermentation which helps to control any harmful bacteria and preserves the vegetables.
Proper fermentation needs:
- The right amount of additive-free salt
- A temperature of 21°C- 24°C (70°F to 75°F)
- No oxygen (achieved by covering the vegetables completely with brine)
- At least 2 weeks and up to 4 weeks for fermentation to complete
Proper salting is critical for successful fermentation. Too little salt is not enough to kill unwanted bacteria while too much salt can stop fermentation so don’t be tempted to adjust the salt in recipes. The best salts to use are pickling salt, canning salt or coarse salt. Read the salt label. Do not use salt that contains iodine or other additives. Iodine can interfere with fermentation and additives can cause your food to be dark or cloudy.
When fermenting, use food-grade plastic containers, glass or ceramics. Don’t use containers that have scratches or cracks which might harbour harmful bacteria. Metal containers (except for stainless steel) may react with the acid in the food and give it a strange flavour or colour. Large ceramic crocks are good for fermenting larger amounts of food.
Salt: the essential ingredient
Fermenting vegetables needs just one extra ingredient: salt. Not all salt is the same. The best salts to use are pickling salt, canning salt or coarse salt. Read the salt label. Do not use salt that contains iodine or other additives. Iodine can interfere with fermentation and additives can cause your food to be dark or cloudy.
Use the right amount of salt. Too little salt is not enough to kill unwanted bacteria while too much salt can stop fermentation. Vegetables need 2.5 percent by volume which works out to 12.5 grams (½ ounce) of salt per 500 grams (1 pound) of vegetables. Weigh vegetables and salt for accuracy.
If you are making a small batch of fermented vegetables, use 10 ml (2 teaspoons) of pickling salt per 500 grams (1 pound) of vegetables.
Vegetables: Salt Volumes and Weights for Best Fermentation
|
Weight of vegetables (grams) |
2.5 % salt by volume (grams) |
|
500 grams |
12.5 grams |
|
1000 grams |
25 grams |
|
1500 grams |
37.5 grams |
|
2000 grams |
50 grams |
|
2500 grams |
62.5 grams |
|
Weight of vegetables (pounds) |
2.5 % salt by volume (ounces) |
|
1 lb |
0.4 ounce |
|
2 lb |
0.8 ounce |
|
3 lb |
1.2 ounces |
|
4 lb |
1.6 ounces |
|
5 lb |
2 ounces |
Dry-salting or brining?
There are two methods for adding salt to the vegetable mixture: dry salting and brining.
Dry-salting is simply adding salt to vegetables. After salting, knead the salted vegetable mixture with clean hands to soften and draw moisture out of the vegetables which creates its own brine. This method is used for vegetables which are chopped, grated or sliced like sauerkraut or kimchee.
Sometimes extra brine is needed for dry salted vegetables to ensure they are fully immersed in brine. Brine excludes oxygen from the mixture which is essential to proper fermentation. Use the brine solution recipe below.
Brining is immersing vegetables in a salt water mixture. This method is better for whole vegetables, like pickles. To make a brine solution, dissolve 1 – 3 tablespoons of salt per 1 quart of water.
Best practices
Use freshly harvested vegetables. Scrub off soil and wash well in cool water. Start fermenting soon after harvesting your vegetables for best results. Do not use store packaged baby carrots or other "ready to eat" vegetables as they may have been treated with food-safe cleaners that will prevent successful fermentation.
Food grade plastic containers, glass or ceramics are good. Don’t use containers that have scratches or cracks which might harbour harmful bacteria. Metal containers (except for stainless steel) may react with the acid in the food and give it a strange flavour or colour. Never use plastic garbage bags or garbage cans for fermenting. Large ceramic crocks are good for fermenting larger amounts of food.
Wash all surfaces, tools and containers used for fermenting. Use hot sudsy water and then rinse well with very hot water.
Use freshly harvested vegetables. Scrub off soil and wash well in cool water. Start fermenting soon after harvesting your vegetables for best results.
If you notice scum on top of the brine, remove it with a slotted spoon. If your fermented vegetables are mouldy, slimy or smell bad, then something has gone wrong. Discard the entire batch.
After fermenting you can put the finished product in smaller clean containers and store them in a cool place like a refrigerator. When temperatures are cooler, fermentation slows down. That’s why fermented foods can be stored for up to three months or longer, without losing their quality and good taste.
If you want to store fermented foods much longer than 3 months, you may wish to can them using recommended processing times for each food. Canning will alter the beneficial organisms that live in your product so if you're very keen on the health benefits of these, you may wish to plan smaller, more frequent batches to ensure they get eaten. There are some fermenting methods that use "starters" from existing ferments where you'd frequently add new produce. This is a different method and does not require canning to maintain long term.
Recipes
We've included some easy recipes below to get you started!
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Sources and further reading
Since it is no longer a common food preservation technique, a lot of people are concerned about fermenting foods. It helps to see other people succeed with recipes you've never considered. There are many fantastic Facebook groups dedicated to fermenting. Join one and see what everyone is doing. The variety of fermented foods people eat may suprise you!
Hertzberg, Ruth; Greene, Janet; Vaughan, Beatrice (2010) Putting Food By: Fifth Edition. New York, New York: Penguin Group (USA) Inc.
Lewin, Alex (2012) Real Food Fermentation: Preserving whole fresh food with live cultures in your home kitchen. Beverly, Massachusetts: Quarry Books.
Cancler, Carole (2012) The Home Preserving Bible. New York, New York: Penguin Group (USA) Inc.
https://www.nmto.ca/sites/default/files/igunaq.pdf
https://www.health.harvard.edu/staying-healthy/fermented-foods-can-add-depth-to-your-diet