Whenever a dish needs a pop of brightness, acidity, or color, I turn to the trusty jar of pickled red onions in my fridge. Made by soaking red onions in a simple vinegar solution, this simple condiment brings acid and crunch to braises, slow-cooked soups and stews, and dark green salads. The gorgeous, magenta-hued strands can turn any one-tone dish (looking at you, pork tenderloin) into a vibrant meal.
I make a batch of pickled red onions every week, filling a clean mason jar with fresh sliced onions, pickling liquid, and herbs or spices. Follow this basic pickled red onion recipe to make your own, then get creative with flavors and seasonings. But first, let’s start with a little science:
Why do pickled red onions turn pink?
Great question. According to culinary scientist Jessica Gavin, the anthocyanins (or coloring pigment) in the red onions react with the acid in the hot pickling liquid to turn the onions a radiant pink. The low pH of the pickling liquid also helps preserve the onions’ crunch, she notes. If you don’t want the vibrant color, you’re better off pickling white onions. But who wouldn’t want a pop of color on their plate? Eat the rainbow, as they say.
How to make pickled red onions:
To make pickled onions, you’ll steep sliced red onions in a vinegar solution (in its most rudimentary form, a 1:1 mixture of water and vinegar, plus sugar and salt). Stash them in the fridge and a day later, you’ll have a jar of fresh pickled onions, ready to add to countless dishes.
This easy recipe for pickled red onions requires just four ingredients and about 12 hours (psst: we’ve also got a shortcut version below, ready in as little as 15 minutes). Once you’ve mastered the basic pickling formula, there are endless ways to experiment—we’ll get into a few variations below. But first, let’s break down the components that go into perfect pickled onions.
Red onions: Red onions have a sharper flavor than white and yellow onions, which makes them ideal for pickling. Slice the onion into rounds, half-moons, or from pole to pole with a sharp chef’s knife or, for the most uniform cuts, a mandoline.
Vinegar: You can make pickled red onions with pretty much any type of vinegar. Distilled white vinegar offers a blank canvas, so the flavorings you add can really shine. But you can use apple cider vinegar, white wine vinegar, champagne vinegar, rice vinegar, or any type you have in the cabinet. I like to enhance the onions’ natural pink color with red wine vinegar.
Water: Cutting the pickle brine with water keeps the vinegar’s puckery punch in check. Recipes generally recommend a 50:50 ratio; for a pickle with more bite, you can use 3 parts vinegar to 1 part water. For one that’s more mellow, skew in the opposite direction. Filtered tap water is fine here—the important thing is to ensure it comes to a boil, as the hot water–vinegar solution will help the sugar and salt dissolve.
