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Pickled red onions

These refrigerator-pickled onions have a crisp bite, a bright pink color, and a clean vinegar tang. Thin slices absorb the lightly sweetened brine evenly, while refrigeration keeps the texture firm.

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Acidity
3% in the liquid
Hands-on
15 min
Jar
1 liter
Keeps
14 days
Thin red onion half-rings in pink pickling liquid in a glass jar.
The onions turn bright pink as they absorb the vinegar brine.

Storing safely

  • Keep the vegetables under the pickling liquid. Anything sticking out can spoil.
  • Use a clean jar and serve with a clean utensil, so no food scraps end up inside.
  • Any film, mold, slime, bubbles, a bulging lid or an off smell: throw it all out, do not taste. When in doubt, throw it out.
  • This has not been heat-processed: always keep the jar in the refrigerator (4 °C / 39 °F or below).

Method

  1. Thoroughly clean a heatproof 1000 ml jar and its lid, then rinse the jar with hot tap water to warm the glass.Use a lid with a plastic lining; vinegar can corrode exposed metal.
  2. Cut 400 g peeled red onions into 2 mm half-rings and place them in the prepared jar.Keep the slices even so they soften and absorb the brine at the same rate.
    Half rings, as thin as you can slice them.
  3. Combine 300 ml distilled white vinegar with 5% acidity, 200 ml water, 20 g granulated sugar, and 10 g fine salt in a saucepan. Bring to a boil at 100 °C (212 °F), stirring for 1 minute until the sugar and salt dissolve.Use food-grade vinegar, never cleaning vinegar.
  4. Pour the hot brine over the onions and gently release any trapped air bubbles. Leave 2 cm (¾ in) of headspace.Slide a clean utensil along the inside of the jar to release air pockets.
    Pouring the hot, still colorless liquid over the raw onion.
  5. Keep all the onions below the brine, adding a small glass weight if the rings float. Pour off excess liquid if needed to maintain 2 cm (¾ in) of headspace.Use a clean glass weight suitable for food contact.
  6. Cover the jar and let it cool briefly, then refrigerate within 1 hour.Do not leave the jar on the counter until it is completely cool.
  7. Let the onions steep in the refrigerator at 4 °C (39 °F) for 24 hours for full flavor.The onions are edible after 1 hour, but their flavor will be less developed.
    After a day in the fridge: bright pink and still crisp.
  8. Keep the jar refrigerated, keep the onions submerged, and use within 14 days. Discard the contents if you notice mold, slime, or an unusual odor.Use a clean utensil each time you take onions from the jar; this is not a shelf-stable preserve.

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When it goes wrong

What you seeLikely causeNext time
Some onion rings remain pale or taste sharply raw.The slices are uneven or have not steeped long enough.Cut even 2 mm slices and allow 24 hours in the refrigerator for full flavor.
Onion rings float above the liquid.The rings are buoyant or air is trapped between them.Release trapped bubbles and use a small glass weight to keep every ring submerged.
Sugar or salt remains visible in the saucepan.The brine was not stirred until fully dissolved.Stir the brine as it comes to a boil and check that it is clear before pouring.
The jar cracks when the brine is added.The glass was cold or not heatproof.Use a heatproof jar and warm it with hot tap water before filling.
The lid shows corrosion.The acidic brine has contacted exposed metal.Use a lid with an intact plastic lining.
The onions are softer than expected.The slices were too thin or the jar stayed warm too long.Cut 2 mm slices and refrigerate within 1 hour.
Mold, slime, or an unusual odor appears.Contamination, exposed onions, or inadequate refrigeration may have allowed spoilage.Discard the contents without tasting; next time, clean the jar thoroughly, keep the onions submerged, and refrigerate at 4 °C (39 °F).
Pickled red onions

Ingredients