Guide to Fermenting Foods

If you mention fermenting foods most people typically think of wine and beer. Beyond these first thoughts of delightful fermented beverages, fermentation is a valuable method of food preservation that has been around for thousands of years. Fermenting foods allowed for longer storage in the absence of refrigeration.  In our modern times fermented foods are simple to produce, have excellent nutritional value, and require little effort to process.  However, similar to other methods of food preservation, in order to be successful you need to first have an understanding of the basic science that is involved.

Fermenting foods is one of the easiest methods of food preservation.  Very little equipment is required. The steps for successful fermentation are easy.



Three Types of Fermentation

  1. Lactic acid fermentation. This is where yeast and bacteria convert sugars and starches into lactic acid. This type of fermentation produces pickles, kimchi, yogurt, sourdough bread, and sauerkraut. 
  2. Ethanol fermentation/alcohol fermentation: This is the process where yeast break down sugars and starches into alcohol and some other byproducts. This is what produces wine and beer. 
  3. Acetic acid fermentation: The fermentation of the sugars and starches in fruit and grains produces a sour tasting product. Examples are vinegar and kombucha. 

How Does Fermentation Preserve Food? 


For this example, I am referring in particular to Lacto Fermentation. The term “lacto” simply refers to a specific species of bacteria known as Lactobacillus. Various strains of Lactobacillus are ubiquitous in the environment. They are commonly found on plants and in our gastrointestinal tract, mouths, and other portions of our body.

Fermentation occurs in the absence of oxygen and in the presence of beneficial microorganisms (microbes) such as bacteria, yeasts, and molds. During fermentation these microbes break down sugars and starches into alcohols. Lactobacillus converts sugars into lactic acid through a natural fermentation process. It was named Lactobacillus because of its ability to easily convert lactose, the sugar in milk, into lactic acid. However, lacto fermentation does not necessarily have to involve dairy products.

The end result of fermentation is the production of an anaerobic (no oxygen), acidic environment. The primary things that cause food spoilage cannot exist in this type of environment. This acidic, anaerobic environment promotes the growth of “good” bacteria and inhibits the growth of “bad” bacteria.  Thus lactic acid in the absence of oxygen acts as a natural preservative and food can be stored for later use. 

This basic process involves chopping vegetables and submerging them in a brine. Keeping the vegetables submerged creates the right conditions for naturally occurring bacteria to proliferate. The salty brine, at the proper temperatures, creates an anaerobic environment and promotes the growth of Lactobacillus. Additionally, at the proper temperatures, the fermentation process is controlled. By doing so, the fermentation occurs slowly and the end product is a pleasant tasting, naturally preserved food that will last for months.  

Six Benefits of Lacto fermentation

1) An easier process

Lacto fermentation can be as easy as chopping vegetables, making a brine, packing the jars and allowing the fermentation process to take over. Food preservation occurs naturally.  This is a very simple process compared to canning food. 

2) Environmentally friendly, sustainable process

Canning and freezing foods uses a lot of energy whether that is gas or electricity. Lacto fermentation requires neither of these things. It is a natural process that will preserve food for months.  

3) Aids in digestion

During fermentation some sugars and starches are broken down. This makes the food easier to digest. 

4) Increased availability of nutrients

Naturally occurring nutrients in foods are not always in a form that our bodies can utilize. Thus they are not “bioavailable”. Fermentation can increase the bioavailability of certain nutrients and vitamins. Our bodies can then readily absorb and utilize them. 

5) Improved Immune Function

The bacteria in your gastrointestinal tract (GI) has a huge impact on your immune system.  Consuming foods that are rich in probiotics helps to promote and maintain healthy types of bacteria in the GI tract.  Our modern, busy lifestyle in addition to a diet high in refined sugars tends to cause a lot of inflammation and promotes GI disorders. Consuming fermented foods can keep that in check and promote a healthy GI tract. Consequently, it improves your immune system. Many fermented foods are also rich in vitamin C, iron, and zinc. All of these elements also aid in strengthening the immune system. 

6) Improved Nutrient Content

Due to the temperatures involved, canning and freezing foods has detrimental affects on vitamins and nutrients.  In many cases, lacto fermentation improves nutrient quality and quantity. 

Common Fermented Foods

  • Kefir: a fermented milk product that tastes like a drinkable yogurt. It is rich in vitamins and minerals, particularly B vitamins and vitamin K
  • Miso: created by fermenting soy beans, brown rice or barley with koji, which is a fungus. This is a traditional Japanese product.  It is rich in minerals, B vitamins, vitamin E, K, and folic acid.
  • Kimchi: a Korean delicacy made from vegetables including cabbage. It contains iron, selenium, calcium, vitamins A, B1, B2, and C. 
  • Aged cheese

  • Yogurt: the most common Lacto fermented food in the United States. It provides a valuable source of probiotics. 
  • Sauerkraut: produced from fermented cabbage. This dish is easy to make at home and rich in multiple vitamins and minerals.  
  • Pickles: contains lots of vitamins, minerals and antioxidants
  • Wine: grapes are mixed with yeast and allowed to ferment
  • Beer: made from fermented mashed grains such as hops and wheat
  • Vinegar
  • Kombucha: This is a fermented black tea with a fizzy taste and a slight alcohol content.  
  • Lassi: This is similar to a drinkable yogurt. 
  • Bread: Sourdough breads are a fermented product. 

Basic Equipment Needed

As with any project, having the right equipment makes the job easier. The tools needed for fermentation are very basic. Consequently, you likely already have most of these in your kitchen.  

  • Cutting board for chopping vegetables
  • Chopping equipment such as a knife, food processor, or mandolin slicer.  Chopping can always be done by hand. However, using some sort of equipment such as a mandolin slicer is much faster and yields consistent thickness of the vegetables.  
  • Blunt meat pounder, potato masher, or similar tool to break up some vegetables and release the juices.  
  • Unrefined salt or pickling salt
  • Freeze dried starter, whey, or kefir grains 
  • Fermenting containers: glass jars, ceramic containers, insert from an old crock pot, glass or ceramic bowl, fermenting crock. DO NOT use metal or plastic containers.

  • Stone crock, lead free clay crock

Keep in mind that a 1 gallon container holds about 5 pounds of vegetables. Therefore,  a 5 gallon crock is sufficient for fermenting 25 pounds of cucumbers.  Be sure that all containers and equipment are washed thoroughly and clean before you start. 

A Basic Recipe for Fermenting Vegetables

This recipe is a great general guideline for fermenting any vegetable. You can add any spices or other dry ingredients according to your choice. You should have fun experimenting.  Keep reading to find three easy recipes which follow this general guideline.   

Yield: One Quart


  • 4 cups of vegetables, washed, cleaned, peeled as needed (carrots), cut to size to fit into the jars of your choice.  
  • 2 tablespoons of sea salt
  • 4 cups of chlorine free water (See note in FAQs about using chlorine free water for fermenting.) 
  • Seasonings of your choice


  • Wash and clean a wide mouth quart jar. Alternatively you can use 2 pint jars
  • Cut vegetables to size to fit into the jar of your choice
  • Add the seasonings of your choice. If using two jars, divide the seasonings evenly.  
  • Mix 2 tablespoons of sea salt with 2 cups of water.  Stir well in order to dissolve all of the salt.  If needed, heat the water slightly but then allow it too cool.  
  • Pour the brine over the vegetables allowing one inch of headspace at the top of the jar. 
  • Place a weight on top of the vegetables to make sure they stay submerged in the brine. You can use a smaller jar that will fit inside the mouth of the larger one. You can also use a rolled cabbage leaf, an apple, or fermentation weights.  
  • Cover the jar. Either use something breathable, such as a coffee filter or cheese cloth, or place a lid on the jar. If using a lid, be sure of open the jar once daily to allow gases to escape. 
  • Leave vegetables to ferment for 2 to 3 days, ideally at a temperature of 60 -75 ℉. 
  • Watch for the formation of bubbles. This is a sign that fermentation is taking place. 
  • Taste vegetables periodically. Refrigerate them after they have reached the flavor of your liking. 

Three Easy Recipes for Fermenting Foods

1) Lacto fermented carrots

Yield 2 pints


  • 1 1/2 pounds carrots
  • 3 cups chlorine free water
  • 2 tsp kosher salt or sea salt


  • Wash and clean two pint jars. No need to sterilize them. 
  • Peel carrots if using whole ones. Cut to size as needed to fit into the jars. 
  • Pack carrots length wise into the jars. Tight packing is okay because they will shrink slightly during the fermenting process. Packing them tightly will help to make sure they stay submerged during the fermentation process. 
  • Dissolve the salt into the water. 
  • Pour the salt brine into the jars leaving 1 1/2 inch of head space.
  • Cover the jar. 
  • Leave at room temperature for 24 to 48 hours.  Allowing to ferment for 1 to 2 weeks makes them taste even better.  
  • Taste them periodically. When they reach a flavor of your liking, refrigerate them. 

2)Fermented Red Onions

Yield 1 pint


  • 2 medium to large red onions
  • 1 tbsp sea salt
  • 2 cups chlorine free water
  • 1 tbsp whey (optional) 
  • Herbs of your choice. 


  • Wash and clean a one pint jar
  • Sliced onions into whole or half rings
  • Pack onions into jars, laying in the herbs of your choice
  • Dissolve salt in 2 cups of chlorine free water. Add the whey (optional)
  • Pour the brine over the onions leaving 1 inch of headspace at the top of the jar. 
  • Weigh the onions down with a fermentation weight, a smaller jar, a rolled cabbage leaf, or a small apple to keep them submerged.  
  • Cover the jar with cheese cloth or a coffee filter. If closing the jar with a lid, then open the jar slightly once daily to allow gases to escape.
  • If the water level rises then pour off some of the liquid.  The fermentation process can draw the natural liquids out of vegetables. This causes the liquid content in the jar to rise.   
  • Allow to ferment at room temperature for 5 to 7 days. 

3)Lacto Fermented Pickles

Yield One quart


  • 6 pickling cucumbers, each about 4 inches long
  • 2 to 3 cloves of garlic, peeled and chopped
  • 3 to 5 sprigs of fresh dill
  • 2 cups chlorine free water
  • 1 1/2 tbsp kosher salt or 1 tbsp salt and 1/4 cup whey


  • Dissolve the salt in the water. If using whey, dissolve the salt first then add the whey. 
  • Wash and slice the cucumbers. 
  • Chop the garlic and dill together and mix with the cucumbers. 
  • Place the mix of cucumbers, dill, and garlic in the jars
  • Pour the brine into the jars. Leave 1 1/2 inch head space. 
  • Cover the jars with something breathable such as a coffee filter or cheese cloth.  Alternatively, close the jar with a lid and open once daily to allow natural gases to escape.  
  • Allow to ferment for 7 to 14 days at room temperature. 
  • Store in the refrigerator. 

FAQs About Fermenting Vegetables

Can plastic containers be used for fermenting or storing veggies?

Food grade plastics are sometimes used for fermenting.  However, plastic containers are easy to scratch and damaged.  These damaged areas can harbor harmful bacteria. Also plastic containers can leach chemicals during the fermenting process. The same is true when storing fermented products in plastic.  It is better to stick with glass or ceramic.

Can you use metal containers for fermenting?

NO. The salt used for fermenting and the lactic acid produced during the fermentation process will react with metal producing a very unpleasant taste. 

How can you tell if fermented vegetables “go bad”?

Vegetables properly fermented are bright and colorful. Batches that go bad usually have a very strong foul odor and turn dark. Fermented vegetables are going to have somewhat of a “stinky smell” to them when you first open the jar. That smell dissipate quickly after the jar is opened.  The number one rule for home processed food: If in doubt throw it out!    

Do you always need a starter culture? 

No. In most cases the bacteria on the vegetables are a natural starter culture . If a recipes calls for a starter culture it is often because it will improve your results, not because it is necessary. This is even the case with sauerkraut and pickles. 

Do fermented vegetables have to be refrigerated?

Fermentation is a natural means of preserving food in the absence of refrigeration.  The lactic acid produced during fermentation prevents the growth of harmful bacteria and acts as a natural preservative.  The fermentation process will continue under refrigeration. The cooler temperature simply slows down the process. Furthermore, by slowing down the fermentation the nice flavor you produced is preserved for a longer time.

Can you freeze fermented veggies?

Freezing  will kill some of the good probiotic bacteria.  However, the veggies are still good if frozen. Fermented veggies do keep for a long time with basic refrigeration. Consequently, freezing is just no necessary.  

Why do I have to use Chlorine free water for fermenting?

The chlorine that is added to most municipal water supplies will inhibit the fermentation process.  Chlorine inhibits the growth of “bad” bacteria as well as the “good” bacteria that is important for fermentation. Some references state that you can allow chlorinated water to sit for 24 hours or boil the water to release the chlorine.  However, some water has chloramine compounds add so this technique is ineffective.  If you are serious about fermenting, then install a filter on your tap that will remove the chlorine.

Why is it important to keep the vegetables submerged in the brine?

Proper and safe fermentation requires that the veggies be in an anaerobic (no oxygen) acidic environment.  If they are not properly submerged in the brine they could become contaminated and ruin your culture. 

What is the best way to keep the vegetables submerged in the brine?

There are several ways to weigh them down.  Use a small glass jar that fits inside the mouth of the fermentation jar. Some people simply use a rock. Use fermentation weights designed for this purpose.  Another option is to use a rolled up vegetable leaf or even an apple to weigh them down.

What about the possibility of food poisoning? 

Lacto fermentation is a very safe process.  This form of food preservation was used prior to the availability of modern refrigeration. If your ferment goes bad you will know due to the very unpleasant odor.  As always, if in doubt throw it out!!  

What is the different between “pickling” and “fermenting?

The standard supermarket pickle is made in a vinegar brine.  Fermenting still produces pickles but now you have a probiotic powerhouse on your hands.  

Do you have to use bottled water?

NO!! In most cases regular tap water is fine to use. However, I do have a water filtration system at the cabin. I produce purified water for less than three cents/gallon AND I am not sending hundreds of plastic bottles per year to the land fill.  

What is the best temperature for fermenting?

About 70 ℉ is best. But, a range of 60 to 75 is acceptable.   If your ferment is too cold, it may not ferment at all.  If it is too warm, it may ferment too quickly and the outcome may not be the best product.  

What kind of salt is best for fermenting foods?

Any salt is suitable for fermenting foods.  But, some are better than others. Generally you want an unrefined salt because it contains many beneficial minerals and nutrients.  Good salts to use are non-iodized sea salt, Himalayan salt, and Kosher salt.  Pickling salt can also be used but it is refined and it may not give you the best results. 

I hope by now you have concluded that fermenting veggies is truly very easy.  There is some basic science behind the process. But if you follow the basic guide lines you will produce a very safe, nutritious product.  Here are some additional resources that have even more ideas and recipes.   

Additional Resources

North Carolina State has a a published guide on Fermentation and Pickling. 

The National Center for Home Food Preservation provides a basic guide for fermenting foods here. 

The folks at Cultures for Health provide a complete downloadable PDF guide on Lacto Fermentation. 

Additional Posts of Interest

Guide to Home Canning

Guide to Freezing Food

Guide to Smoking Meat

Guide to Dehydrating Foods

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