Binurong Pulang Sibuyas (Fermented Red Onions)

Encouraged by how frequently I use the fermented garlic in my meals, I decide to ferment another Filipino staple, onion. 

I use red onion for this recipe because of its pleasant color and, more importantly, better nutritional profile than the milder white variety. It has anthocyanin, the antioxidant that is responsible for the blue, purple, or red color in natural foods, known for being among the most nutritious.

Red onions are high in Vitamin C, B vitamins, and potassium. They have the potent anti-inflammatory quercetin that fights cancer, decreases the risk of heart disease, and helps lower blood pressure. The sting and strong smell of red onions is due to its high sulfur content that also inhibits tumor growth. Both the sulfur compounds and quercetin have anti-diabetic benefits such as lowering blood sugar.

Many of these amazing benefits of onion are better reaped when it is eaten raw. Understandably, this can discourage a lot of people. I find that fermentation tempers the bite of raw onion and the lactic sourness brings out some of its sweetness. So do not be put off by the pungency when you burp the jar. The longer you ferment the onions, the more tempered the flavor. 

Feel free to add spices and aromatics too, such as dahon ng laurel, curry leaves, or mustard seeds. When fermenting the white variety, add some turmeric and black pepper for a bright golden color and additional benefits from the curcumin and piperine.


  • 2 large red onions
  • 1 cup of filtered water
  • 2 tsp salt


  1. Wash the onions thoroughly and slice thinly into half moons. Transfer the onions into a jar.
  2. Dissolve salt in the water and pour the brine into the same jar with the onions.
  3. Use a fermentation weight to make sure that the onion slices are submerged. Make sure to have at least an inch of headroom.
  4. Let ferment for at least 7 days. Burp at least once a day. Store in the fridge once you like the taste.

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