How to Make Lacto-fermented red onions

Lacto-fermented Red Onions Recipe

Red onions, water, salt and a starter culture are all it takes to make lacto-fermented red onions. They are not as common as pickled onions but they're easier to make, tastier and healthier!

Course Side Dish
Cuisine Any
Prep Time 15 minutes
Total Time 15 minutes
Servings 12 ounces
Author Craig Fear


  • 2 medium red onions, sliced into rings
  • 1/2 - 1 TBSP sea salt
  • 12 ounces filtered water
  • 1 TBSP whey, optional
  • Herbs of your choice, optional


  1. Pack sliced onions firmly into 12 ounce glass jar.  Layer in any herbs you want.
  2. Dissolve salt in 12 ounces of filtered water and add whey.
  3. Pour brine over onions and tilt jar a few times to mix well.  Leave one inch between the top of the jar and the top of the brine. Use a weight (find a good source for fermenting weights here) to keep the onions under the brine, if necessary.
  4. Let sit on counter for three to seven days. Use an airlock lid (find a good source for airlock lids here) or burp the jars (meaning just open them) every day to let out the gasses that are a natural byproduct of fermentation.  If the water level rises, simply pour some out.
  5. Enjoy on salads, burgers or anywhere you usually use red onions.  Fermented red onions will have a sour albeit less pungent flavor than unfermented ones.