Name: Apple Jelly
Ingredients: 1 pail of sour apples; water (enough to cover the apples); 1 lb sugar; lemon (to taste)

Why it works: Apple and lemon are a kitchen classic. They rank in the top 14% of all ingredient pairs, and cooks put them together in 7,551 recipes. Both carry trans-2-nonenal, which smells cardboard, fatty. The science ↓

Apple Jelly

Ingredients

1 pail of sour apples
water (enough to cover the apples)
1 lb sugar
lemon (to taste)

Directions

Boil the sour apples in enough water to cover them.
Let the mixture drain through a fine sieve.
For every pint of juice, add 1 lb of sugar and lemon to taste.

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.

Apple + lemontop 14% of all pairs

Smell alikemoderate

Cooked together7,551 recipes

Shared aroma: trans-2-nonenal (cardboard, fatty).
Apple + sugartop 18% of all pairs

Smell alikelow

Cooked together16,478 recipes

Shared aroma: beta-damascenone (apple, rose).
Sugar + lemontop 18% of all pairs

Smell alikelow

Cooked together53,532 recipes

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

Apple and sugar barely smell alike, yet cooks put them together in 16,478 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

Sour apples: Provide the pectin and acidity that help the juice set into a jelly.
Sugar: Adds sweetness and helps the juice thicken into a jelly when cooked.
Lemon: Adds acidity that brightens the flavor and supports setting.