Skip to main content
Main

Pickled Onions

A pickled onion recipe using onions, coarse sea salt, vinegar, and mustard, soaked in saltwater and then pickled in vinegar.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 4 ingredients
Jump to recipe ↓

Why it works: Onion and mustard match in chemistry and in kitchens. They rank in the top 6% of all ingredient pairs, and cooks put them together in 9,259 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Pickled Onions

Ingredients

Directions

Soak the onions

  1. Peel the onions.

  2. Soak them in a weak saltwater solution for six days, changing the water every other day.

Pickle

  1. Boil vinegar with two handfuls of coarse sea salt and let it cool completely.

  2. Pour the cooled vinegar over the onions.

  3. Add 2 tablespoons of mustard for each quart of pickled onions for extra flavor.

Recipe from a historical cookbook (Internet Archive).

Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.

Explore the science

The flavor team

The pairs that carry this dish. Each one is judged two ways: how much their aromas overlap, and how often cooks already put them together.

  1. Onion + mustardtop 6% of all pairs
    Smell alikestrong
    Cooked together9,259 recipes

    Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).

  2. Vinegar + mustardtop 7% of all pairs
    Smell alikemoderate
    Cooked together14,067 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  3. Onion + vinegartop 14% of all pairs
    Smell alikemoderate
    Cooked together18,226 recipes

    Shared aroma: acetic acid (sour, vinegar).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

What each ingredient does

Onions
Form the body of the pickle, softening slightly while absorbing the brine and vinegar flavors.
Vinegar
Adds acidity that sharpens the flavor and helps preserve the onions.
Mustard
Adds sharp, pungent flavor that complements the sourness of the vinegar.

The step that matters

Let the vinegar cool completely before pouring it over the onions. Hot vinegar would partly cook the onions, softening their texture and dulling their crispness. Cooled vinegar brines them gently and keeps a firm, crunchy bite.

Swap the onion

How well each one fits the dish's main ingredients (vinegar, mustard):

  1. Horseradishfits better
  2. Radishfits better
  3. Lettucefits better
  4. Onionthe original

Fit is the average pairing score against vinegar, mustard. Candidates are from the same food group and used in at least 100 recipes.

“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.

More pickled onions recipes

and Apples 3and Cucumbers 3 See all 163 →

You might also like

Tomato SoupTomato Soup526 recipesBrown BreadBrown Bread461 recipesMutton BrothMutton Broth292 recipesYorkshire PuddingYorkshire Pudding264 recipes