Fermented Quick Pickled Red Onions

by Kaitlynn Fenley

How do you quick pickle and ferment red onions at the same time? Easy, you just need sauerkraut brine, apple cider vinegar, lime juice and some thinly sliced fresh red onions!

The Best Pickled Red Onions

The way I ferment red onions is different from the way I usually ferment other vegetables. I’ve done quite a few fermented red onion recipe tests using traditional wild fermentation techniques… and I wasn’t too fond of them. So I turned to my other favorite method of fermentation called wild heirloom culturing. This method employs using sauerkraut brine (or any fermented vegetable brine) and apple cider vinegar to ferment fresh vegetables using wild heirloom cultures found in the fermented brine. 

This method of fermentation is more similar to yogurt fermentation than it is to something like sauerkraut fermentation… and it’s very similar to refrigerator pickling, but with beneficial microbes included.

Lacto Fermented Red Onions

I know you may be curious why the traditional lacto fermentation process isn’t great when trying to ferment onion.

Basically you don’t want to wild ferment any vegetables that are high in fructose and fructans, because it leads to more of an effervescent alcohol fermentation. This is true no matter how much salt you use.

So if you can just dump already acidic brine with a lot of Lactobacillus already present, you can skip the first two stages of wild fermentation (you know the part with all the bubbles). Lactobacillus bacteria only make lactic acid, they can’t make alcohol. So the onions still ferment, but only the desirable fermentation occurs.

Making Fermented Onions

Supplies You Need:

Fermented Red Onions

In this recipe we will still ferment red onions, but this is a different kind of vegetable fermentation: We call this wild heirloom culturing. I made it up one day, and it’s phenomenally delicious. We use wild fermented sauerkraut brine and apple cider vinegar to culture the onions with wild Lactobacillus. This method only requires a 48 hours fermentation time, before refrigerating.

Always Trust your sense of smell: Fermented onions should smell pleasantly sour and a bit oniony. Never eat anything that smells repulsive. 

Never eat anything that had mold growing on it: By following directions you should not encounter this problem.  The effectiveness of this recipe does depend on the quality of wild fermented sauerkraut you use. If sauerkraut was not fermented properly, or to completion, you may encounter effervesce or yeast growth over time.

Taste test at 48 hours: If you prefer the onion to be more tart and sour, let them ferment 12 more hours.

Apple Cider Vinegar Pickled Onions

These fermented quick pickled red onions are very easy to make, and since they are made with already fermented vegetable brine and apple cider vinegar, not much can go wrong. you just need to remember a few things:

  • Keep your fermenting red onions at a temperature between 70-80 degrees F. Keep out of direct sunlight
  • Since this is a fermentation with added cultures from the sauerkraut brine, you only need to ferment the onions for a short time.
  • Keep refrigerated and consume within 6 months for full probiotic benefits!

Inspired By Mexican Pickled Red Onions

I also use lime juice in this recipe, which gives it the a similar flavor profile to Mexican pickled red onions. The pickling process with the lime juice included mellows the pungent flavor of the red onions. In just a few hours, they are perfectly flavorful and balanced with a pleasant acidity.

Recipes with Pickled Onions

Here’s a short list of some of my favorite recipes you can use these fermented quick pickled red onions in:

Print

Fermented Quick Pickled Red Onions

How do you quick pickle and ferment red onions at the same time? Easy, you just need sauerkraut brine, apple cider vinegar, lime juice and some thinly sliced fresh red onions!

  • Author: Kaitlynn Fenley
  • Prep Time: 10 minutes
  • Total Time: 10 minutes
  • Yield: 16 Ounces 1x
  • Category: Fermented Foods
  • Method: Fermentation
  • Cuisine: Mexican
  • Diet: Vegan

Ingredients

Scale
  • 200 Grams Chopped Red Onion
  • 5 Grams Sea Salt
  • 100 Grams Raw Apple Cider Vinegar
  • 200 Grams Sauerkraut Brine
  • the juice of one small lime
  • Mustard Seeds or peppercorns

Instructions

  1. Wash your fermentation equipment (jar, weight and lid)
  2. Peel then wash your red onions in cool water. Using a knife, slice your onion to desired thickness.
  3. Place your kitchen scale on the counter. Turn it on and set it to weigh in grams.
  4. Place a mixing bowl on your kitchen scale and tare/zero* the scale. 
  5. Add chopped onion into the bowl on your scale until the scale reads 200 grams.
  6. Remove the bowl from your scale and set aside. Place your empty, clean mason jar on the scale, and tare/zero the scale. Make sure your scale is still set to grams and add 200 grams of Sauerkraut Brine and 100 grams of apple cider vinegar to the jar. Add the juice of one small lime
  7. Add the 200 grams of onions from your bowl, into the mason jar.
  8. Place a small bowl on your scale and tare/zero the scale. Weigh out 5 grams of salt. Then add the 5 grams of salt to the jar of onions.
  9. Add in about a teaspoon of mustard seeds or peppercorns (optional). 
  10. Place your standard mason jar lid on the jar, and secure. shake the jar vigorously for 2 minutes.
  11. Leave at room temperature for 8 to 24 hours, stirring the onions a couple of times, then refrigerate.
  12. Refrigerate for at least 1 hour before serving.

Notes

*This recipe works best in a 16-20 ounce jar. 

*Taring/zeroing the scale with a container on it subtracts the weight of the container, allowing you to weigh only what is added to the container. After taring/zeroing the scale, the scale should read 0.0 with the container on it.

Keywords: red onions, pickled onions, fermented onions

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8 comments

Wolf April 1, 2020 - 7:28 pm

Does using vinegar in this recipe kill the beneficial bacteria?

Reply
Kaitlynn Fenley April 2, 2020 - 2:13 pm

No, the beneficial bacteria thrive in acidic conditions.

Reply
Nerissa April 18, 2020 - 3:00 am

Hello. A great recipe thank you, I love fermenting but adore vinegar Ed onion and pickles, so a great combo. Is there an alternative to the sauerkraut brine? I have whey from milk kefir, could I substitute with that please.

Reply
Kaitlynn Fenley April 18, 2020 - 2:15 pm

You’re welcome! The only alternative is brine from other fermented vegetables, like pickles or kimchi.

You cannot use whey from milk kefir for this type of fermenting because milk kefir contains yeast.

Reply
Paul Haldane April 24, 2021 - 9:38 am

Your great!!

Reply
Carleen May 13, 2021 - 8:08 pm

Does the ACV HAVE to be raw? I only have regular ACV on hand.

Reply
Kaitlynn Fenley May 14, 2021 - 6:38 am

No, it does not have to be raw. The regular will work fine.

Reply
Allan May 18, 2022 - 2:55 pm

Hi this differs slightly from the low sodium recipe you have for carrots. You put the jar in the fridge to ferment for 48 hours as apposed to 48 hours for this recipe before refrigeration. How does this change the end product when comparing both techniques? Does the additional salt in this recipe effect the fermentation or is it for taste?

Reply

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