Ice-Bath Onions: Taming the Allium

A short little post for a stellar back-pocket kitchen technique to elevate, and tame, a simple ingredient: raw onion.

The method could barely be easier: Soak sliced (or chopped) raw onions in an ice bath for 20 to 30 minutes. Drain. Eat.

The cold water neutralizes many of the sulfur compounds responsible for the strong, almost hot, taste of onions. In doing so, the onions lose that characteristic bite, allowing the pure flavor and subtle sweetness to shine through. (Heating, as you might have guessed, has the same effect — think how soft and mellow caramelized and grilled onions can be.) Raw onions soaked in water with ice will also get very crisp.

We like it with any of the bulb onions (e.g., Vidalia, yellow, white, or spring bulb onions), but are most partial to red onions for their bright color + added nutritional benefits that come with blue/purple produce.

These are a terrific topping for smoky chilli, spicy Indian dishes, and grilled pork, poultry, red meat, and seafood. Imagine they’d do equally as well with your favorite sausage, burger or even meatballs, or with meatless options like grilled eggplant, portobellos, tofu or tempeh. I’m excited to experiment with socca flatbread + one of our Friday night homemade pizza soon.

Tops on our list so far is tucking the crisp red onions into grilled fish tacos with lime-cilantro peppers and a cumin-spiked grilled pineapple-cabbage slaw. Perfect with an ice cold IPA, a glass of fresh and bright white or rosé wine, or even a light Pinot Noir as we enjoyed!

What’s in it for me?

One serving of sliced onions (about 8 to 10 thin rings, or roughly 1/2 cup) offers approximately 25 calories, 1 gram (g) protein, 6 g carbohydrate, only 2.5 g sugar, and virtually zero sodiumfat, and cholesterol. This serving also provides about 7% of your daily vitamin C needs, 5% of your vitamin B6, and 4% that of fiber.

The bright purple-y color of red onions indicates the presence of anthocyanins (a type of flavonoid) and lycopene (a type of carotenoid) — potent antioxidants that promote heart health and cancer-fighting benefits. In addition, the sulfur compounds (characteristic of Alliums (e.g., garlic and other stalk + bulb onions) help the body synthesize the antioxidant glutathione — a powerful anti-inflammatory that helps increase the health of your immune and cardiovascular systems, and has been linked to prevention of some cancers.

Soaking your raw onions in an ice water bath is one of those little ideas that can make a big difference — minimizing the sharp, spicy pungency, while maximizing sweetness and crunch. No burn, no overpowering taste, and little to no risk of that lingering onion aftertaste. If you have older onions that are otherwise a bit sad and limp, this trick can also be a means of revival.

A fast, flavorful and fresh twist to this basic everyday ingredient you probably have in your kitchen already, it’s a simple trick you can and should try this summer!

Cheers, Heather

Tell me… What are your favorite dishes to top with raw onions?

Ice-Bath Onions
Prep Time
Cook Time
Total Time
Recipe Type: condiment, veg
Makes: approximately 1 cup
  • 2 cups cool or cold water
  • Handful of ice cubes
  • 1 medium to large red onion, peeled
  1. In a medium bowl, stir together the water and ice cubes to make an ice bath. Set aside.
  2. Use a sharp knife to slice the whole onion into thin rings. Alternatively, cut the onion in half, then cut into thin slices or any size dice you like. Add the onions to the ice bath, and give the contents a good stir. Set the bowl aside to soak at least 20 to 30 minutes, up to 2 hours; does not need to be refrigerated, but won't hurt if you have the space.
  3. When ready to use, drain the onions well (pat dry, if you like) and use immediately, or refrigerate, covered, up to 1 hour until needed.
HGN Notes
This method also works for other bulb-type onions, e.g., Vidalia, yellow, white, or spring bulb onions.

+ Boost flavor by splashing in a bit of lime or lemon juice, or cider or wine vinegar. Really amp it up by swapping the water entirely for one of these alternatives. (You may need to add a bit of honey or pinch of sugar to balance the vinegar, however.)
+ Add 1 Tbsp fresh or 1 tsp dried herbs for a subtle background note -- chives, oregano, thyme, rosemary or sage sound good.
+ Sprinkle over a pinch of hot red chilli flakes to give it a spicy kick.
+ Cut the bite entirely with this Cook's Illustrated recommendation to soak the onions for 15 minutes in a baking soda solution (1 Tbsp per 1 cup water): (Haven't tried, but CI is always on point with food science tips.)
Nutrition Info
Serving Size: 8 thin slices Calories: 25 Fat: 0 Saturated fat: 0 Unsaturated fat: 0 Trans fat: 0 Carbohydrates: 6 Sugar: 2.5 Sodium: 2 Fiber: 1 Protein: 1 Cholesterol: 0

+ + + +

Check out my downloadable nutrition guides.

p.s. I love hearing from you! Check back if you ask a question, because I’ll answer it here.

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