Last Updated on June 1, 2025 by Nico
Lacto-fermented onions are high in probiotics and make a tangy addition to hamburgers and salads. They are simple to prepare and make a healthy condiment or side dish.
Lacto-fermented vegetables are so simple to make. I originally learned to ferment vegetables as a way to preserve the veggies I bought at the farmer’s market. I still preserve vegetables in this way but I also love to ferment staples veggies like onions and garlic in order to consume more probiotics. Beyond those, I have also tried fermenting carrots, tomatoes, garlic, and jalapenos.
Fermenting staple vegetables, like onions or garlic, gives you a bump of probiotics without changing much in your diet. Once you have fermented onions or garlic on hand, you just need to swap them with regular onions and garlic.
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Tips
There are two important things to keep in mind when fermenting vegetables.
First, it is important that you use enough salt in the salt water brine. I like to use two tablespoons of salt per quart of water. If you’re making a larger or smaller amount, just multiple or divide by 2.
The second important thing to keep in mind is that the vegetables are kept below the brine while the fermentation process is happening. I like to use a fermenting weight but you can also use a Ziploc bag with water in it or a rock or something else that’s heavy.
FAQ
I like to consume my fermented veggies within three months of putting them into cold storage.
You can lacto-ferment any veggie. Fermented cucumbers make delicious pickles, fermented cabbage makes sauerkraut, and more. For most vegetables the process remains the same – you simply chop it up, pour a salt water brine overtop, and leave it on the counter for a week or so.
Yes, any lacto-fermented vegetable has probiotic benefits to your body.
Lacto-fermented onions have a taste similar to raw onions, but are more tangy and less biting.
We like to use lacto-fermented onions on top of hamburgers, hotdogs, in salads, quiches, and eggs, or as a tangy side dish.
Tools
Two Pint Mason Jars
Measuring Cups And Spoons
Fermenting Weight (or a Ziploc bag with water)
Ingredients
Onions
Water
Salt
For complete measurements, see the printable recipe card below.
Photo
Instructions
Chop the onions and add them to a quart mason jar. I like to chop mine into half moons.
Add two tablespoons of an unadulterated salt into a separate quart jar.
Boil water. Dissolve the salt by pouring boiling water into the jar with the salt.
I like to fill the quart jar with the salt ¼ of the way full with boiling water, stir the salt until it dissolves, and then fill the rest of the quart jar with cold water or ice. This is to cool down the boiling water enough so it’s safe to pour over the vegetables right away.
It’s important to avoid pouring boiling water over vegetables you would like to ferment. This is because good bacteria, which facilitate the fermentation process, can be killed by boiling water. You need those bacteria in order to fermented vegetables so it’s important to cool the salt water brine down to room temperature.
After the salt water brine is room temperature, pour it over top of the chopped onions in the mason jar.
Place a fermenting weight on top of the onions and ensure that they are completely below the brine.
Place a loose lid on the jar and leave it on the counter for about a week. After a week or so, taste an onion and see if you like the flavour.
If you do, remove the weight, tighten the lid, and store the onions in the fridge for 2-3 months. If you would like them more fermented, simply replace the weight and leave them on the counter for a few more days.
What to read next
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10 Simple Lacto-Fermentation Recipes
Simple Lacto-Fermented Carrots
Simple Strawberry Kefir Smoothie Recipe For Gut Health
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Healthy Probiotic Lacto-Fermented Onions
Ingredients
Method
- Chop the onions and add them to a quart mason jar. I like to chop mine into half moons.
- Add two tablespoons of an unadulterated salt into a separate quart jar.
- Boil water. Dissolve the salt by pouring boiling water into the jar with the salt.
- I like to fill the quart jar with the salt ¼ of the way full with boiling water, stir the salt until it dissolves, and then fill the rest of the quart jar with cold water or ice. This is to cool down the boiling water enough so it’s safe to pour over the vegetables right away.
- After the salt water brine is room temperature, pour it over top of the chopped onions in the mason jar.
- Place a fermenting weight on top of the onions and ensure that they are completely below the brine.
- Place a loose lid on the jar and leave it on the counter for about a week. After a week or so, taste an onion and see if you like the flavour.
- If you do, remove the weight, tighten the lid, and store the onions in the fridge for 2-3 months. If you would like them more fermented, simply replace the weight and leave them on the counter for a few more days.
Nutrition
Video
Notes
- It is important that you use enough salt in the salt water brine. Use two tablespoons of salt per quart of water.
- Keep in mind is that the vegetables need to be kept below the brine while the fermentation process is happening. I like to use a fermenting weight but you can also use a Ziploc bag with water in it or a rock or something else that’s heavy.
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