Fermented Foods | How Do You Make Fermented Foods? | Fermented vegetable recipes
How do you make fermented foods?
It's particularly easy to ferment vegetables safely at home, but it is an exact science. When done correctly fermenting vegetables is a great way to spice up recipes and to add probiotics to your diet.
What kind of vegetables can you ferment?
Mostly all water dense vegetables, as long as you use the right salt concentration and ferment your foods for the right amount of time.
We do not suggest fermenting beets or carrots by themselves due to the sugar content. Also, when we say "Vegetable Fermentation" we are not referring to the fermentation of pulses (beans) or starchy root vegetables.
Why You Should Ferment Vegetables
Fermented Foods are extremely nutritious and fermentation is a delicious preservation method. Fermented vegetables are packed not only with probiotics, but also with essential vitamins, nutrients, minerals and prebiotic fiber necessary for health and wellness.
One third of the foods in the average diet are fermented by our wonderful microbial friends! Fermentation has been around for thousands of years, but long ago it was probably just thought of as a magical occurrence that happened when food was salted, placed in an oxygen free environment or both. However, fermentation is no magic, it’s a science with wondrous and fascinating explanations. A lot of foods in the world are fermented, or rely on some sort of product of fermentation for flavor, preservation or texture. Even all natural shampoo products rely on fermentation byproducts for the sudsy nature of the product.
First and foremost, though, vegetable fermentation has always been a method of preserving harvests for long winters.
Apart from our commercial fermented foods company, we enjoy fermenting whatever is in season from the local farmers market. We also grow a few vegetables on our apartment patio seasonally, and sometimes resort to fermenting when we can’t eat our homegrown veggies quickly enough.
Our vegetable ferments are made solely with salt, vegetables, seasoning and purified water. We focus on microbiology, and we use science to ferment... Uniquely, all of our ferments are checked under the microscope bi-weekly to see what stage they are in. This allows us to include approximate, recipe specific fermentation timelines in all of our fermentation blog posts, helping keep you and your ferments healthy.
What Is Fermentation?
When we talk about fermenting vegetables, we are specifically referring to a microbial process called lactic acid fermentation. This particular fermentation occurs when certain bacteria produce lactic acid as a byproduct of fermenting plant compounds for energy. All it takes is the addition of a very specific salt concentration to vegetables, and you can turn plain old vegetables into flavor rich superfoods. It’s important to remember that you are not actually fermenting, microbes are fermenting. You just have to set the right microbes up for success.
Particular concentrations of salt pave the way for creating a happy home for lactic acid bacteria, and all the microbes needed to get the fermentation process started are already on your vegetables, even after you wash them. The coolest thing about fermented vegetables is that the probiotic microbial population will be different for different vegetables!
First, for the best probiotic microbes to thrive and produce lactic acid (the substance that actually preserves the vegetables) we have to encourage the delicate process of bacterial succession. Bacterial Succession is when the growth and metabolism of certain types of bacteria increase, permanently altering the environment. This leads to the death of those bacteria and the take over different types of bacteria. As one type of bacteria dies off, the next type takes over until the ferment reaches a point with perfect living conditions for species of Lactobacillus (which are the probiotic microbes).
When using wild natural microbes to produce fermented foods, bacterial succession takes time and occurs in three stages that take about 3 1/2 weeks. We call these stages the three microbial stages of fermentation.
Bacterial succession and the stages of fermentation are what make fermented veggies safe, delicious and nutritious!
Once a vegetable ferment reaches stage three there is a very selective environment within the fermentation vessel. It’s salty, acidic, and oxygen free. In this selective environment only probiotic bacteria can thrive; bad microbes have died off and are inhibited from growing.
The Microbiology of Fermented Vegetables
Stage one: Stage one of microbial fermentation begins as soon as you add the salt to your veggies. There are many bacteria naturally on your vegetables that can tolerate salt, and the ones that utilize oxygen proliferate first. In this stage it's the Gram-negative rod shaped species of bacteria, like Enterobacter cloacae and Erwinia herbicola, that thrive. In the brine-vegetable mixture, these bacteria use up all the oxygen present and make the brine into an anaerobic (oxygen free) environment. Once all the oxygen is used up by the stage one microbes, and the brine is now an anaerobic environment, we enter into stage two.
Stage Two: The second stage begins about two or three days past the start of fermentation. At this time the stage one bacteria have died off, and Leuconostoc species of bacteria populate. Leuconostoc species are lactic acid bacteria that tolerate salt and acid. They are Gram-positive cocci shaped, heterolactic fermenters (heterolactic means that they produce two different acids.) Lactic acid, ethanol and carbon dioxide along with small amounts of acetic acid and glycerol are produced when these bacteria thrive. This is the bubbly stage! During stage two you want to look for bubbles in the form of carbon dioxide being produced. (Be sure to burp the fermentation jar during this stage if using a sealing lid, like a mason jar lid). In stage two the environment becomes more acidic, leading us into stage three.
Stage Three: This stage begins after about six to eight days from the start of fermentation. The bacterial population mostly consists of Lactobacillus species in stage three. Lactobacillus species are salt-tolerant, acid-tolerant, homolactic fermenters. They are considered homolactic fermenters because the one main product from their metabolism of plant compounds is lactic acid. The microbial metabolism of plant sugars into lactic acid results in an acidic pH of about 3.1 - 3.7. The lactic acid produced in this stage is what preserves the vegetables. Once stage three is reached you’ll have a fermentation environment that is anaerobic, salty and acidic which is very selective and only allows for the growth of good bacteria. You want to give your ferments time to be in stage three for a bit, so that the lactic acid bacteria have adequate time to produce adequate amounts of their wonderful preserving substance. We always wait about two weeks after this stage is reached, because that time yields a safe pH and a perfectly pleasant sour taste. It is okay to vary this time just a bit though. It is fine to taste test, refrigerate and eat at about 12 days past reaching stage three, (which would be around three weeks total time).
A couple of important factors influence the creation of a perfect fermentation environment, though. First, to reach stage three and to prevent unwanted microbes in your ferments, vegetables MUST stay in an anaerobic environment; you must keep the produce you are fermenting submerged in the anoxic brine created in stage one. Using a fermentation weight is best to accomplish this. You also should keep your ferments at a favorable temperature of 21-24 degrees C (about 71-75 degrees F) and not in direct sunlight. Lastly a steadily decreasing pH is needed; pH strips are great for checking the progress of pH as your ferments move through the stages.
Supplies You’ll Need to Start Making Fermented Foods
To summarize: No, you do not need a fancy expensive jar & no, you absolutely do not need a starter culture or whey for fermenting vegetables.
What you do need:
Mason Jar lid or a Pickle Pipe lid
Metal mason jar screw band or Rust Free Plastic Band
Large jar or pitcher for mixing salt water brine
The produce you'd like to ferment
How Much Salt Do You Use in Fermented Foods?
Always use a high quality salt, such as Cultured Guru Fermentation salt.
Its important to remember that different types of salts weigh different amounts, so using volume measurements like tablespoons or cups is very inaccurate. For example, a teaspoon of a flake salt weighs half as much as a teaspoon of small grain Himalayan salt. You must use mass to calculate a salt concentration. A 1% salt difference is quite a lot to tiny microbes with delicate living parameters, so it is vital to weigh the salt to create the best fermented vegetables! Visit our How Much Salt blog to learn more.
The easiest way to ferment almost any vegetable:
Add 10 grams of salt per 400 grams of vegetables and water combined. Use this ratio to set up a proportion and find the salt you need based on the amount of vegetables and water you’ll be fermenting.
Example 1: If you have 400 grams of cucumbers and 400 grams of water, that’s 800 grams total. So you will add 20 grams of salt. (use the proportion 10/400 = x/800)
Example 2: if you have 700 grams of cabbage and 500 grams of water, that’s 1,200 grams total. Using the proportion 10/400 = x/1200 x = 30 grams.
This is just a simpler way to say: Multiply the total weight in grams of your vegetables and water by 2.5%. Add the result (in grams) of salt to your vegetables and water.
Some vine growing vegetables (like peppers and zucchini) do well with a bit higher salt concentration, around 3%.
Tips on Making Fermented Foods
Stay below the brine.
There is a lot of talk on the internet about what jars and lids are truly air tight, and which ones really "keep oxygen out"... air tight lids are nice to have, but a jar with a proper fitting lid will do fine (such as a mason jar and matching mason jar lid). As far as lids go, you just want to prevent evaporation. Creating an anaerobic environment within the brine, and keeping your veggies submerged in that brine is what's most important. The best way to do this is by using a fermentation weight. Recall that in the first stage of microbial fermentation all the oxygen is depleted from the brine. This means that as long as you keep all the vegetables submerged within the anoxic brine in the jar, it's okay if your lid is not perfectly air tight; you will have a successful fermentation!
Trust your senses.
When your ferments reach the time for stage two, you should look for bubbles. At the proper time, this is the first indicator that your fermentation is on its way to success! Your sense of smell is your greatest ally in fermenting. Smells should be pleasantly sour, never pungent or repulsive. Your senses will let you know when something shouldn't be eaten, so trust your nose! If you do not know what raw fermented greatness smells like, then you can easily buy some of our delicious, raw sauerkraut to smell and eat!
Our fermentation timelines are pretty accurate when you follow the recipe and the directions exactly. This means using the same ingredients, same supplies and keeping your ferments at the same temperature and light conditions will yield almost the same timeline for the stages of fermentation. If you vary the recipe that's fine too! Just be patient. If you have doubts that your ferments have made it to stage three and lingered there a bit, let them sit for a little longer time. A few extra days is better than too few days!
Concentration is important.
Don't just add more salt as a solution to a fermentation problem. It will not help. Salt concentration is very important to tiny microbes because their living parameters are delicate. If you do not have enough brine in to fully submerge your vegetables, just make some more!
Add 2.5 grams of salt per 100 mL of water to make a salt brine solution perfect for topping off vegetables when you didn’t end up with enough brine.
Fungus among us or a funky smell.
If you have a fungus/mold/film/stinky smell in your ferment, I'm sorry but you need to throw it out and start over. You cannot simply scrape off fungus. Just because you don't see it after scraping it out, doesn't mean it isn't there. Fungus indicates that bacterial succession is not occurring properly. Repulsive smells are also definite indicator that something went wrong, and the ferment needs to be thrown away. If you have a curbside compost service or a personal compost bin, a great way to dispose of bad ferments is to compost them. Remember that your sense of smell is your number one sense in fermenting! Trust your nose!