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Fruits & Roots

Fermented Quick Pickled Red Onions

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

Prep: 10 minutes
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Ferment | Fruits & Roots

Fermented Quick Pickled Red Onions

How do you quick pickle and ferment red onions at the same time? You need sauerkraut brine, apple cider vinegar, lime juice and 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 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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Fruits & Roots

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5 from 6 reviews

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!

  • Prep: 10 minutes
  • Total Time: 10 minutes

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

Did you make this recipe?

Please leave a 5-star review below if you loved it! Tag @cultured.guru on Instagram

 

Nutrition information is auto-calculated and estimated as close as possible. We are not responsible for any errors. We have tested the recipe for accuracy, but your results may vary.

author avatar
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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hey i’m kaitlynn, i’m a microbiologist and together with my husband jon we are cultured guru.

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  1. Wolf
    04|01|2020

    Does using vinegar in this recipe kill the beneficial bacteria?

    Reply
    1. Kaitlynn Fenley
      04|02|2020

      No, the beneficial bacteria thrive in acidic conditions.

      Reply
  2. Nerissa
    04|18|2020

    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
    1. Kaitlynn Fenley
      04|18|2020

      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
  3. Paul Haldane
    04|24|2021

    Your great!!

    Reply
  4. Carleen
    05|13|2021

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

    Reply
    1. Kaitlynn Fenley
      05|14|2021

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

      Reply
  5. Allan
    05|18|2022

    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
  6. Carolyn Gamboa
    08|10|2022

    Hello,
    Where can one obtain sauerkraut brine ?
    Thank you,
    Carolyn Gamboa

    Reply
    1. Kaitlynn Fenley
      08|10|2022

      It’s the liquid in a jar of homemade or store bought fermented sauerkraut.

      Reply
  7. Sketti
    08|22|2022

    Where can I purchase it bag gorgeous jar featured in the video?

    Reply
    1. Kaitlynn Fenley
      08|23|2022

      The jar is linked in the body of this blog post. In the equipment list.

      Reply
  8. APinDC
    11|09|2022

    Thanks for the recipe. Going to try it later today. I understand (or at least think I do) the precise ratios of brine, acv and salt but…Why is it 200g of onions?

    Reply
    1. Kaitlynn Fenley
      11|09|2022

      Because all the ingredient measurements are precise. I write all my fermentation recipes in grams, requiring a kitchen scale.

      Reply
  9. Fay
    12|30|2022

    This recipe was a hit! I’m wondering if I can reuse the brine from the first time I made this recipe without adding the ACV? Or do I use the brine and still add ACV? Or am I not able to use this brine at all?

    Reply
    1. Kaitlynn Fenley
      01|03|2023

      You can re-use it about twice before it becomes less acidic and not good for preserving the onions. When you reuse the brine from the previous batch, add more ACV.

      Reply
  10. Amanda
    01|02|2023

    Can I use beet brine instead of sauerkraut brine?

    Reply
    1. Kaitlynn Fenley
      01|03|2023

      No, it needs to be sauerkraut brine.

      Reply
  11. Ray
    02|19|2023

    I’m experienced in fermenting cauliflower. Can I use the brine from my cauliflower fermentation process instead of sauerkraut juice? I also use kosher salt. May I use that instead of the sea salt?

    Reply
    1. Kaitlynn Fenley
      02|20|2023

      yes and yes 🙂

      Reply
  12. MsLinda
    04|25|2023

    Hello,
    I have some kimchi brine and some sauerkraut brine but not 200 grams of either. Can I combine the two to get a total of 200 without ruining the recipe or the process?
    Thanks

    Reply
    1. Kaitlynn Fenley
      04|26|2023

      Yes! You can combine them. I bet it will be delicious!

      Reply
  13. Melissa Humphries
    09|05|2023

    Had a few issues. First of all, I made the Saurkraut from your site in preparation to make this recipe. I didn’t realize until I was already making this recipe that I would have needed 2 jars of Saurkraut because I only had 100 gram worth from 1 batch. I used water to sub. Is that Ok?
    The second issue is that my 16 ounce mason jar overflowed at 500 grams so the spice and lime weight sent it spilling over. I pushed the onions and dumped out enough liquid to leave an inch of space at the top of the jar. Then reset the scale to 0 to ensure I added the right salt concentration. Hope this was the right move. Wondering if I somehow added too much of something or if my batteries are weak but I use my scale all of the time and rarely mess it up. I added 100 grams ACV, 200 brine (w/ water mixed in to bring to weight), 200 onions, 20 grams seeds, 37 grams lime.

    Reply
  14. Melissa Humphries
    12|06|2023

    I made this again because they were the best pickled red onions I have tasted. Plus a great way to use up the kraut juice in the bottom of a few containers. I also encountered the same problem as before. There is too much liquid for 16 ounce jar and I had 4 about ounces leftover that would not fit in the jar. Seeing how this is a pickle more than a ferment, I didn’t worry about that too much and just made an extra 8 ounce jar worth from the leftover brine and cut up as many red onions that would fit. The kraut brine really does add something different in a very good way. I wish I had more kraut brine but after we finish a jar we usually only have about 70 grams of brine leftover so it takes 3 jars before I have enough to make this recipe. Plus the color is just sooo beautiful!

    Reply
  15. JF
    01|02|2024

    Hi!
    I’ve been long time looking for low fodmap onions, are these ones low fodmap? Have the Lactobacillus enough time to eat the fructans in 24/48 hours?

    By the way, in the main text it says let it for 48 or 54 hours, but in the instructions section says just 24 hours, not sure wich one is the right one.

    Thank you so much!

    Reply
    1. Kaitlynn Fenley
      01|04|2024

      When I had fructan intolerance, these onions worked great for me. But everyone is different, you can let them sit at room temperature for longer if you want.

      Reply
      1. JF
        01|27|2024

        Hi Kaitlynn, thanks for the advice. I tried it and it’s amazing. I can’t wait three weeks for my new brine to make them again! And no fructans effects.

        By the way, I’ve done a lot of yours recipes but I’m not sure about a white growth thing in cucumbers and peppers. It’s not a pellicle or sediment at the bottom but a white stripe on the side of the vegetables, what could it be?

        Thank so much for sharing your knowledge.

        Reply
  16. Valerie
    03|12|2024

    Would the liquid from store-bought probiotic fermented red onions work for this recipe? Or would sauerkraut brine work better? Excited to try this!

    Reply
    1. Kaitlynn Fenley
      03|13|2024

      That can probably work! I’ve only ever made them with sauerkraut, kimchi and pickle brine though.

      Reply
  17. Clive
    03|30|2024

    Could you give imperial measurements? I get so frustrated trying to convert from metric, that I don’t even try metric recipes. Thanks.

    Reply
    1. Kaitlynn Fenley
      04|01|2024

      I only have the recipe as written and did not test it with imperial measure. You can use google to convert if you’d like.

      Reply
  18. Janet
    04|10|2024

    Could I replace them Lime with a lemon or orange?

    Reply
    1. Kaitlynn Fenley
      04|10|2024

      yes!

      Reply
  19. Cathleen Luoma
    04|18|2024

    Could you use liquid from store bought peperoncini?

    Reply
    1. Kaitlynn Fenley
      04|18|2024

      If they’re fermented, it should work great!

      Reply
  20. Leanne
    04|28|2024

    Can you use whey in place on the sauerkraut brine?

    Reply
    1. Kaitlynn Fenley
      05|03|2024

      I haven’t tried it, but it might work!

      Reply
  21. John Carson
    07|25|2024

    Definitely NOT fermentation . Pickling

    Reply
    1. Kaitlynn Fenley
      07|25|2024

      It is absolutely fermentation. Try reading the body of the blog post and learn something.

      Reply
  22. stacy
    08|17|2024

    SO delicious! My family loves this recipe! I just want to make sure I understand correctly – I can reuse the brine from the first batch of fermented quick pickled red onions that I made from your recipe to make another batch by putting in another sliced red onion and some additional ACV? How much additional ACV? It can only be reused once or twice?

    Thank you!

    Reply
    1. Kaitlynn Fenley
      08|18|2024

      yes, you can reuse the brine a couple times. Top with enough ACV to submerge the onions. I only reuse it 2-3 times before starting over with fresh brine.

      Reply
  23. C. Patterson
    09|02|2024

    Hi – the intro indicates 48 hrs. at room temper this type of fermentationf, the recipe shows 8-24 hrs before refrigeration. Could you comment? Thanks!

    Reply
    1. Kaitlynn Fenley
      09|03|2024

      It’s a preference thing. I fixed the wording of the part you’re referencing. Recipe needs at least 8-24 hours, but you can leave it culturing at room temp for up to 48 hours.

      Reply
  24. Georgie
    09|18|2024

    After shaking it up, you place the pickle pebble/weight on top of the onions, correct? And then does it need a pickle pipe lid or no?

    Reply
    1. Kaitlynn Fenley
      09|18|2024

      You can use a fermentation weight, but you don’t have to for this kind of fermentation since its so short. Also, I never recommend those silicone lids. a regular jar lid works better.

      Reply
      1. Georgie
        10|05|2024

        Okay. Thank you. I was just about to ask on your basic pickle recipe about using the silicone pickle “pipe”… so you wouldn’t suggest that? I’m afraid I’ll forget to burp it! I bought them before researching them at all… can you explain why you don’t recommend them?
        Also, wondering about replenishing the onions… You can reuse the brine, right? Do you just pull the jar out of the fridge, add more onions and repeat 24 hours on the counter and then move to the fridge? TIA! 🙂

        Reply
  25. Georgie
    10|11|2024

    Wondering about replenishing the onions… You can reuse the brine, right? Do you just pull the jar out of the fridge, add more onions and repeat 24 hours on the counter and then move to the fridge? TIA! 🙂

    Reply

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sourdough discard 🤝 cottage cheese combined tw sourdough discard 🤝 cottage cheese

combined two of the best fermented foods to make the best pancakes. And yes, you can ferment the batter overnight in the fridge for easier digestion. 

My recipe makes 15 pancakes and each serving of 3 pancakes had 17 grams of protein! 

Get the recipe from my recipe index, linked in my profile✨

#sourdough #cottagecheese #pancakes #fermentation
It can suppress overgrowth of Candida albicans, wh It can suppress overgrowth of Candida albicans, while boosting good bacteria in your gut! 

Roasting garlic increases beneficial garlic compounds like diallyl sulfide and diallyl disulfide — or DADS, for short. Both of these compounds have been studied for their anti-inflammatory (anti-cancer), antioxidant, and antifungal properties.

It’s definitely a sauerkraut you should keep in your rotation.

To get the recipe google “garlic sauerkraut.” and you’ll see mine it’s the first one.

Sources:
PMC8777027 (Diallyl Disulfide (DADS) Ameliorates Intestinal Candida albicansInfection by Modulating the Gut microbiota and Metabolites and Providing Intestinal Protection)

https://doi.org/10.3390/fishes9100401 (diallyl disulfide (DADS) shows a substantial increase, with concentrations rising from 1.6 mg/g in non-fermented garlic to 4.8 mg/g in its fermented counterpart, suggesting enhanced bioactivity through fermentation)
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I know, I know, I’m making everything with cottage cheese right now. But how can I not? Cottage cheese is one of the most protein-rich fermented foods.

If you love ice cream and cheesecake-like flavor, you’ll love this recipe. it’s high in protein, requires only four simple ingredients, and does not require churning. So, you do not need an ice cream maker!

A half-cup serving of this ice cream has 12 grams of protein, making it a healthy and balanced sweet snack. Get the recipe from the recipe index linked in my profile. 

#cottagecheese #icecream
Baked ✨Cottage Cheese✨ Queso Dip It’s crea Baked ✨Cottage Cheese✨ Queso Dip 

It’s creamy, cheesy, and packed with protein, but with fewer calories thanks to the cottage cheese base. And it’s only 6 ingredients +toppings! 

I love it topped with cilantro, diced tomatoes, onions and fresh jalapeños! 

Get the full recipe from my recipe index, linked in my bio. 

#queso #cheese #cottagecheese
Why do you add water to sauerkraut? To that I as Why do you add water to sauerkraut? 

To that I ask: who told y’all you can’t add water to sauerkraut? 

Adding water standardizes my recipes, making sure everyone gets enough brine, regardless of cabbage variability. 

Google “cultured guru sauerkraut” and you’ll see my recipes! 

#sauerkraut #fermentation
Bok choy is similar in texture to Napa cabbage and Bok choy is similar in texture to Napa cabbage and lovely for fermentation. 

Since bok choy and all cabbages grow low and very close to the soil, their microbiome composition is wonderful! This makes all cabbages easy vegetables to ferment, and fermented bok choy is one of my absolute favorites.

Google fermented bok choy and you’ll see my recipe, it’s the first one. ☝🏼 #cabbage #fermentation #homestead 

Ps. I used some tiny weck jar lids for weights in my bigger weck jar and it worked great!
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