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Sauce

Tomato Catsup

A homemade tomato ketchup made by stewing tomatoes with spices, straining, reducing, and bottling.

From an old cookbook · modernised transcription
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Why it works: Allspice and mustard match in chemistry and in kitchens. They rank in the top 2% of all ingredient pairs, and cooks put them together in 1,928 recipes. Both carry methyleugenol, which smells clove, spice. The science ↓

Tomato Catsup

Ingredients

Directions

Make the ketchup

  1. Combine the tomatoes, salt, allspice, red pepper, and ground mustard in a bowl and mix thoroughly.

  2. Stew in the vinegar for 3 hours.

  3. Strain the mixture through a sieve.

  4. Simmer the strained liquid until it reduces to 1 quart.

Bottle

  1. Pour into bottles and seal tightly.

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. Allspice + mustardtop 2% of all pairs
    Smell alikestrong
    Cooked together1,928 recipes

    Shared aroma: methyleugenol (clove, spice).

  2. Allspice + peppertop 5% of all pairs
    Smell alikestrong
    Cooked together6,395 recipes

    Shared aroma: estragole (anise, licorice).

  3. Tomato + peppertop 7% of all pairs
    Smell alikemoderate
    Cooked together17,923 recipes

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

  4. Mustard + vinegartop 7% of all pairs
    Smell alikemoderate
    Cooked together14,067 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  5. Pepper + mustardtop 9% of all pairs
    Smell alikemoderate
    Cooked together15,430 recipes

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

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

What each ingredient does

Skinned tomatoes
Form the main body of the ketchup and provide most of its liquid and flavor.
Vinegar
Adds acidity that gives the ketchup its tang and helps preserve it.
Salt
Seasons the sauce and draws out flavor from the tomatoes.

The step that matters

Simmer the strained liquid until it reduces to 1 quart. Simmering evaporates water and concentrates the tomato solids, thickening the sauce and deepening its flavor. Stopping too early leaves it thin and watery, while reducing too far makes it pasty.

Swap the tomato

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

  1. Horseradishfits better
  2. Radishfits better
  3. Shallotfits better
  4. Tomatothe original

Fit is the average pairing score against allspice, pepper, mustard, vinegar. 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.

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