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Tomato Catsup

A thick tomato sauce made by boiling tomatoes with vinegar, spices, onions or garlic, salt, and red peppers.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 8 ingredients
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Why it works: Allspice and clove match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 7,874 recipes. Both carry estragole, which smells anise, licorice. The science ↓

Tomato Catsup

Ingredients

Directions

Prepare

  1. Wash and chop the tomatoes.

Cook and strain

  1. Combine tomatoes, vinegar, allspice, cloves, black pepper, onions or garlic, salt, and red peppers in a large pot.

  2. Boil the mixture for a long time until it thickens.

  3. Strain through a sieve and add the vinegar last.

  4. Continue boiling until it reaches the desired thickness.

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 + clovetop 1% of all pairs
    Smell alikestrong
    Cooked together7,874 recipes

    Shared aroma: estragole (anise, licorice).

  2. Clove + peppertop 5% of all pairs
    Smell alikestrong
    Cooked together17,451 recipes

    Shared aroma: ethyl octanoate (fruity, wine).

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

    Shared aroma: estragole (anise, licorice).

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

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

  5. Tomato + oniontop 8% of all pairs
    Smell alikemoderate
    Cooked together20,633 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

Tomatoes
Provide the main body, flavour and bulk of the ketchup.
Vinegar
Adds acidity that gives the ketchup its sharp tang and helps preserve it.
Onions or garlic
Add savoury depth and aroma to the sauce.
Red peppers
Contribute colour, sweetness and vegetable flavour.

The step that matters

Boiling until thick. Long boiling evaporates water and concentrates the tomato solids, so the sauce thickens. Stopping too early leaves it thin and watery, while the acid from the vinegar keeps the flavour bright as it reduces.

Swap the onion

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

  1. Capsicumfits better
  2. Mustardfits better
  3. Carrotfits better
  4. Onionthe original

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