Fermented Quick Pickled 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 fermented sauerkraut brine (or any fermented vegetable brine; brine is the liquid in a jar of already fermented vegetables) 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 for fermenting onions.

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

If you can dump already acidic brine with a lot of Lactobacillus 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:

• 16 oz Wide Mouth Mason Jar
• Fermentation Weight to fit your mason jar
• Standard Metal Mason Jar Lid (this can rust in the presence of salt)
• OR Rust Free Plastic Lid
• Unrefined Sea Salt
• Scale
• Mixing Bowl 
• or you can use a Weck Jar (which is what is pictured here)

Fermented Red Onions

We will still ferment red onions in this recipe, 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 24-hour fermentation time before refrigerating, but you can let it go for up to 48 hours before refrigerating.

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

Never eat anything that has 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 is not fermented correctly or to completion, you may encounter effervesce or yeast growth over time.

Taste test at 24 hours: If you prefer the onion to be more tart and sour, let them ferment for 12-24 more hours before refrigerating.

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 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 it refrigerated and consume it within 6 months for full probiotic benefits!

Inspired By Mexican Pickled Red Onions

I also use lime juice in this recipe, giving it a flavor profile similar to Mexican pickled red onions. The pickling process with the lime juice mellows the intense flavor of the red onions. They are flavorful and balanced with a pleasant acidity in just a few hours.

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:

• No-Mayo Roasted Garlic and Herb Potato Salad
• Summer Lemon Kale Salad with Brined Salmon
• Easy Greek Meatballs with Tzatziki Sauce Dressing
• Nutritious Chicken Caesar Salad with Brussels Sprouts

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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!

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• Prep: 10 minutes
• Total Time: 10 minutes

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Ingredients

• 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

*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.

this recipe works best with a 16-20 ounce jar

Kaitlynn Fenley Author, Educator, Food Microbiologist

Kaitlynn is a food microbiologist and fermentation expert teaching people how to ferment foods and drinks at home.

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