Fermented Onion Relish - A Relish That You Are Sure To Relish.

Fermented Onion Relish - Main Ingredients

About The Recipe

It is believed that onions originated in central Asia before rapidly spreading across the world. Without a doubt, they have become a universal flavoring ingredient in cooking. In fact, they are an integral part of Asian cuisine; where they’re used with meats, fish, seafood, poultry or enjoyed in soups and salads. Without onions, many curries would lose their oomph, the world renowned “French Onion Soup” would not exist, and this beautiful Fermented Onion Relish could never be achieved. Fermented onions are super delicious, healthy, and make a colorful addition to any meal.

Health Benefits

While making you cry on the outside, onions make you happy on the inside by providing your body with layer upon layer of health giving nutrients. Interesting fact: most of an onion’s beneficial nutrients are concentrated in the outer layers. So, in the future stop peeling as soon as you’ve removed the outermost paper layer. Onions are high in beneficial polyphenols. Polyphenols increase the ratio of beneficial bacteria in your gut. Remember a healthy gut equals a healthy immune system. Here’s a condensed list of some of the onion’s more curative properties:

  • Onions have anti-inflammatory properties that help with joint pain and arthritis.
  • Onions help prevent diabetes by assisting in regulating blood sugar.
  • Onions are rich in Quercetin, a powerful antioxidant, which fights against cancer-causing free radicals. Repeated tests have shown that onions lower our risk of certain types of cancer like colorectal cancer, laryngeal cancer, and ovarian cancer
  • The large amounts of Biotin present in onions maintain healthy skin.

Let’s Get started

This onion relish makes a wonderful gift. Not only because it’s brimming with probiotic goodness but also because it doesn’t have that overwhelming vinegary taste like many of the store bought varieties. Make up a huge batch and offer jars to friends and family over Christmas, Hanukkah, birthdays or just because. Get organised with some pretty ribbons and labels and you’re good to go. The sweet, tangy flavor goes particularly well with cheese and crackers or in burgers or sandwiches.  Another plus is the long shelf life. Once ready this ferment will keep in the fridge for up to 18 months.

What You Need

  • 4 Large red onions, sliced into rings (adjust quantity for jar)
  • 1 Tbsp. mustard seeds
  • 2 Tsp. ground cumin
  • 1 Tbsp. sauerkraut brine
  • 1 1/2 Tbsp. Salt - No iodine
  • Easy Fermenter Lids 
  • Fermenting Weights 


  1. Mix all ingredients together in a large bowl.
  1. Spoon onion mix  into a pre-sterilized, wide mouth mason glass jar leaving as little headroom as possible.
  1. Cover the jar with the Easy Fermenter Lid and place the Fermentation Weights in the jar to ensure perfect fermentation results.
  1. Store in a cool, dark place (room temperature 60-70°F is preferred,) for 1 to 2 weeks. You can start to check if the ferment is nearing completion after about 7 days.
  1. Once jar has been opened, move to cold storage. The flavor will continue to develop with time.

Variations To The Ferment

Red onions can be substituted with yellow or white. To sharpen the flavor even more, garlic and/or chili could be added to the mix along with your choice of herbs. Instead of sauerkraut brine, whey powder could be used as a handy bacterial starter to put the fermentation process into gear. Or, you could try straining your own organic greek yogurt at home to collect the whey in liquid form to add to your ferments.

Visual Guide


Want To Take Your Fermenting To the Next Level?

Enroll in our Fermenting Mastery Video Series. A complete set of detailed, step-by-step instructions that will give you the confidence to create ferments that you’re proud of, every single time. Even when you make up your own recipes and techniques! Included are 14 professionally recorded recipes - Over two hours of content to help you master your ferments.