Pickled Red Onions

250 g	red wine vinegar
250 g	water
200 g	sugar
12 g	salt
400 g	red onion, halved and sliced thin through root end

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red onion,: Red onions get their color from the presence of anthocyanins, a type of compound present in many other colorful foods, including fruits like red grapes and cherries. If you’ve ever pickled red onions, you know that when the hot, acidic liquid of your pickling solution hits the sliced onions, their color goes from dull reddish purple to a bright, intense pink. The culprit of this color change are those colorful anthocyanins. At low pH (approximately pH 3 and below), anthocyanins are positively charged and tend to have a red color. At higher pH (pH 4-5), anthocyanins are nearly colorless and carry no charge. As the pH increases (to approximately pH 8 and above), anthocyanins can gain a negative charge and are blue. The pH sensitivity of anthocyanins is responsible for many of the pesky color changes we see in food, such as the grey-blue color of blueberries cooked in alkaline quickbreads.

1 cup red wine vinegar

1 cup water

1 cup (7 ounces) sugar

2 teaspoons salt

2 red onions, halved and sliced thin through root end

Hide Annotation

red onions,: Red onions get their color from the presence of anthocyanins, a type of compound present in many other colorful foods, including fruits like red grapes and cherries. If you’ve ever pickled red onions, you know that when the hot, acidic liquid of your pickling solution hits the sliced onions, their color goes from dull reddish purple to a bright, intense pink. The culprit of this color change are those colorful anthocyanins. At low pH (approximately pH 3 and below), anthocyanins are positively charged and tend to have a red color. At higher pH (pH 4-5), anthocyanins are nearly colorless and carry no charge. As the pH increases (to approximately pH 8 and above), anthocyanins can gain a negative charge and are blue. The pH sensitivity of anthocyanins is responsible for many of the pesky color changes we see in food, such as the grey-blue color of blueberries cooked in alkaline quickbreads.

- 250 g red wine vinegar
- 250 g water
- 200 g sugar
- 12 g salt
Whisk vinegar, water, sugar, and salt together in medium saucepan and bring to boil over high heat. Cook, whisking frequently, until sugar and salt dissolve, 2 to 3 minutes.
- 400 g red onion, halved and sliced thin through root end
Meanwhile, transfer onions to large jar or bowl. Pour hot pickling liquid over onions and let cool for 20 minutes. Cover and refrigerate until onions turn pink and are seasoned throughout, at least 8 hours. Strain onions and serve. (Onions can be refrigerated in pickling liquid for up to 2 weeks.)

- 1 cup red wine vinegar
- 1 cup water
- 1 cup (7 ounces) sugar
- 2 teaspoons salt
Whisk vinegar, water, sugar, and salt together in medium saucepan and bring to boil over high heat. Cook, whisking frequently, until sugar and salt dissolve, 2 to 3 minutes.
- 2 red onions, halved and sliced thin through root end
Meanwhile, transfer onions to large jar or bowl. Pour hot pickling liquid over onions and let cool for 20 minutes. Cover and refrigerate until onions turn pink and are seasoned throughout, at least 8 hours. Strain onions and serve. (Onions can be refrigerated in pickling liquid for up to 2 weeks.)