Name: Watermelon Preserve
Ingredients: 4 cups sugar; 8 cups watermelon juice; watermelon rind, sliced; 2 cups sugar (for rind); 1 lemon, sliced; spices (in a bag)

Why it works: Sugar and lemon are a kitchen classic. They rank in the top 18% of all ingredient pairs, and cooks put them together in 53,532 recipes. Both carry 2-nonenal, which smells fatty, green. The science ↓

Watermelon Preserve

Ingredients

Directions

Prepare the juice

Cut the red part of the watermelon and boil until soft.
Squeeze the watermelon through a colander to extract the juice.

Cook the preserve

Combine 4 cups of sugar with 8 cups of watermelon juice and boil for 30 minutes.
Add the sliced watermelon rind and 2 cups of sugar, then boil for 2 hours.
Slice the lemon and add the spice bag, then boil for another hour.

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.

Sugar + lemontop 18% of all pairs

Smell alikelow

Cooked together53,532 recipes

Shared aroma: 2-nonenal (fatty, green).

Sugar and lemon barely smell alike, yet cooks put them together in 53,532 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

Sugar: Sweetens the preserve and helps it thicken as it cooks down.
Watermelon rind: Provides the bulk of the preserve and absorbs syrup as it simmers.
Lemon: Adds acidity that brightens the flavour and supports setting.

“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.