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Tomato Catchup or Catsup

A homemade tomato ketchup made by boiling ripe tomatoes, seasoning, and reducing the juice.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 5 ingredients
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Why it works: Tomato and pepper are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 17,923 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Tomato Catchup or Catsup

Ingredients

Directions

Prepare the tomatoes

  1. Collect fully ripe tomatoes before frost.

  2. Squeeze or bruise them well.

  3. Boil slowly for 30 minutes.

  4. Strain through a cloth.

Season and reduce

  1. Add salt, pepper, and spices to taste.

  2. Add horseradish if desired.

  3. Boil again. Remove any scum.

  4. Continue boiling slowly until about half of the juice is reduced.

  5. Let it cool.

Bottle and store

  1. Pour into clean glass bottles. Cork tightly.

  2. Store in a cool place.

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

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

  2. Pepper + horseradishtop 11% of all pairs
    Smell alikemoderate
    Cooked together2,646 recipes

    Shared aroma: coumarin (sweet, hay).

  3. Tomato + horseradishtop 13% of all pairs
    Smell alikemoderate
    Cooked together415 recipes

    Shared aroma: coumarin (sweet, hay).

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

What each ingredient does

Fully ripe tomatoes
Provide the main body, sweetness and acidity that the sauce is built on.
Salt
Seasons the sauce and sharpens its overall flavour.

The step that matters

Continue boiling slowly until about half of the juice is reduced. Long, gentle reduction thickens the sauce and concentrates its flavour. Boiling too hard or stopping too early leaves it thin or scorched.

Swap the horseradish

The recipe marks horseradish as optional. How well each one fits the dish's main ingredients (tomato, pepper):

  1. Capsicumfits better
  2. Eggplantfits better
  3. Carrotfits better
  4. Horseradishthe original

Fit is the average pairing score against tomato, 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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