Fermented Red Onions

I LOVE fresh and pickled red onions... a lot. We always have red onions in our house and we never, ever run out. We put them in quinoa bowls, in burrito bowls, on avocado toast, and pretty much any savory meal. Want to know what we love more than pickled red onions though? Fermented Red Onions! It's the same great taste of pickled red onions, but with an awesome purpose: gut health! 

We fermented some for two weeks and some for four weeks, and they are delicious! I prefer the four week fermented batch because they are just a bit more tart. Four weeks allows for the Lactobacillus in stage three of the fermentation to make more lactic acid, dropping the pH a bit more, and allowing the flavor to develop. 

If you are curious what the elusive "good for your gut" Lactobacillus look like here is a picture from my microscope:

 
 

  This is a diluted sample of the two week fermented red onion brine. It's rich in probiotic Lactobacillus and there are still a few Leuconostoc bacteria remaining. The chain of rod shaped bacteria in the middle is Lactobacillus. The two little round bacteria to the right are Leuconostoc bacteria. The big blob to the left is a piece of onion.  I love using microscopy, because it validates the safety and probiotic quantity of everything we ferment.  When developing recipes we always keep the focus on the microbes, whats best for selecting just friendly species of microbes, and what allows for a high population of those friendly microbes. Then we share recipes like this based on science and facts! 

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Fermented Red Onions

Ingredients

Takes

Brine Method: The brine method we use to make fermented Red Onions is to chop and then weigh the onions and add 2.5% of that weight in salt, then to add a 2.5% salt water solution. The brine method will be explained in the recipe steps. Read the science behind salt conenctration here.

We highly recommend just investing in a kitchen scale for about $10 from Target or Amazon. If you're going to master fermentation and select for the best probiotic bacteria in your ferments, you'll need one to weigh salt. Weighing is the only way to create an accurate salt concentration.  The scale we use in our home kitchen is this one.

Instructions

  1. First, make a 2.5% saltwater brine. To do this, put an empty large jar on your kitchen scale, and tare the scale. Fill the jar with warm filtered water and record the weight of the water (in grams).
  2. Next multiply the weight of the water by 0.025, the number you get is the amount in grams of salt you need to add to the water.
  3. Place a small separate bowl on your scale and tare the scale. Weigh out your Fermentation Salt in grams. 
  4. Add your salt to the water and stir it in until it dissolves. Then let the mixture cool. 
  5. While the salt water cools, chop your onions however you desire. I perfer to chop the onions in slivers.  
  6. Place an empty bowl on your kitchen scale and tare it. Place the chopped onion in the bowl and record the weight in grams. Using the same math method, multiply the weight of your chopped onion by 0.025. The number you get is the grams of salt you need to add to the chopped onion.
  7. Place a small separate bowl on your scale and tare the scale. Weigh out your Fermentation Salt in grams. 
  8. Add your salt to the onions and mix until evenly distributed. If mixing with your hands, you may want to wear gloves so your hands dont stain purple or smell like onion.
  9. Once you have mixed the onion and the salt thoroughly, it is time to add the mixture into a jar. We used a pint sized mason jar for this recipe. Before you add in the onion pieces, you need to dump any liquid from the bowl into the jar. Then add in all the onion pieces.
  10. Place a fermentation weight in the jar to hold everything down. Then once the saltwater brine you made is cool, pour it over the onions and fermentation weight until everything, including the fermentation weight is submerged. 
  11. Store your fermentation jar in a cool place out of direct sunlight. It should be kept in an area that stays around 70-75 degrees F
  12. During the first few days of fermentation carbon dioxide and  bubbles will be produced. During this time you will need to burp the jar. To burp the jar, just remove the lid to let the gas out and check to make sure everything is still submerged below the brine. You must make sure that your fermentation weight and onions are staying submerged BELOW the brine. You may have to press everything down with a spoon/tamper a few times. 
  13. When fermenting onions you should not experiance a loss of brine. But if you do lose brine during the first few days (which is possible in very full jars when bubbles are produced) use steps 1-4 to make a salt solution to replace the lost brine. Replacing lost brine can only be done during the first 4-5 days. Adding brine after that will dilute acid present in the ferment, disrupt bacterial sucession, and cause the ferment to not be properly preserved. 
  14. The onions should ferment for 2-4 weeks, so that all the stages of bacterial succession can occur. The time line is a little different from a cabbage fermentation, due to a different micorbial population on onions. 2-4 weeks also allows enough time for the final stage Lactobacillus bacteria to produce enough lactic acid to drop the pH to preservation levels. Visit our Science of Fermentation blog to read more about the stages of fermentation!
  15. We tracked our onions throughout the fermentation process. By checking the progress of microbial stages under the microscope we have provided you with this handy timeline! If you follow our recipe and directions, your timeline of red onion fermentation should approximately match ours!

    24 - 72 hours: all contents in the jar should be submerged beneath the brine. At this time there are still Gram negative bacteria and possible pathogens present.

    72 hours - 5 days: After 72 hours you should start to see lots of bubbles being produced. This is the stage in which you will burp the jar. This is when the ferment enters stage two of vegetable fermentation. Leuconostoc bacteria begin to thrive and produce a lot of carbon dioxide. Gram negative organisms die off.

    5 - 14 days: The bubbles in the brine will decrease, as the ferment leaves stage two and enters stage three. The red onions will become cloudy and start to develop a pleasant sour smell. The onions will also start to turn fully pink. Lactobacillus species are most abundant during this time period.

    14 - 28 days: Lactobacillus make up majority or all of the microbial population. They produce copious amounts of lactic acid, and make the ferment smell even more pleasantly sour. This is the time in which the vegetable mixture becomes preserved. This is when you want to smell and taste test.

    30 days: Wait for the onions to smell and taste as you like, and refrigerate when you find the smell and taste most pleasant! We like ours best when we refrigerate at about 30 days, but they are also good at around 15-20 days. The longer the red onions ferment, the more the flavors develop.

Peace, Love and Probiotics,

Kaitlynn Fenley

Kaitlynn Fenley