Name: Blackberry Jam
Ingredients: blackberries; ½ cup sugar; 1 tablespoon lemon juice (optional)

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 ↓

Blackberry Jam

Ingredients

blackberries
½ cup sugar
1 tablespoon lemon juice (optional)

Directions

Boil the blackberries and sugar together for 40 minutes.
Cover closely and keep in a dry, 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.

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

Blackberries: Provide the fruit body, flavor, and pectin-containing pulp that forms the jam's structure.
Sugar: Sweetens the jam and helps it thicken and keep by binding water.
Lemon juice: Adds acidity that brightens flavor and supports pectin set.

“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.