Skip to main content
Main

Tomato Catsup

A thick tomato sauce made by boiling tomatoes, onions, mace, and pepper until it fills two bottles.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 5 ingredients
Jump to recipe ↓

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 Catsup

Ingredients

Directions

Prepare the tomatoes

  1. Wash the tomatoes and remove the stems.

  2. Place the tomatoes in a pot over medium heat without adding water.

  3. Sprinkle with salt and boil steadily for 1 hour, stirring frequently.

  4. Strain the mixture through a colander, then through a sieve.

Make and bottle the ketchup

  1. In a pot, combine the strained liquid with chopped onions, mace, and black pepper.

  2. Boil until the mixture is thick enough to fill two bottles.

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

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

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

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

  3. Onion + peppertop 11% of all pairs
    Smell alikemoderate
    Cooked together68,474 recipes

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

  4. Mace + peppertop 16% of all pairs
    Smell alikelow
    Cooked together12,257 recipes

    Shared aroma: myristicin (spice, warm).

  5. Onion + macetop 17% of all pairs
    Smell alikelow
    Cooked together7,078 recipes

    Shared aroma: eugenol (clove, spicy).

Mace and pepper barely smell alike, yet cooks put them together in 12,257 recipes: they work on texture and structure more than aroma.

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 liquid that reduces into the thick ketchup.
Coarse sea salt
Seasons the tomatoes and helps draw out their juices during cooking.
Chopped onions
Add savoury depth and aromatic flavour to the strained tomato base.
Mace
Adds a warm, aromatic spice note that complements the tomatoes.
Black pepper
Adds a mild, pungent heat and aroma to the sauce.

The step that matters

Boil until thick enough to fill two bottles. Ketchup thickens only as water evaporates during long, steady boiling. Stopping too early leaves a thin sauce that may spoil, while over-reducing makes it pasty.

Swap the mace

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

  1. Garlicfits better
  2. Cuminfits better
  3. Thymefits better
  4. Macethe original

Fit is the average pairing score against tomato, onion, 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.

More tomato ketchup recipes

Green 26 See all 523 →

You might also like

Tomato SoupTomato Soup526 recipesCream of Tomato SoupCream of Tomato Soup107 recipesTomato BisqueTomato Bisque61 recipesCream Tomato SoupCream Tomato Soup28 recipes