Name: Watermelon Pickle
Ingredients: 1 watermelon rind, cut into 1-inch pieces; ½ cup coarse sea salt (formerly 'bay salt'); 1 tablespoon powdered alum; 2 quarts water (for alum solution); 1 cup sugar (for syrup); 1 quart water (for syrup); 2 cups vinegar; 6 cups sugar (for final syrup); Spices (tied in cheesecloth)

Why it works: Sugar and syrup match in chemistry and in kitchens. They rank in the top 6% of all ingredient pairs, and cooks put them together in 5,842 recipes. Both carry ethanol, which smells alcoholic, ethereal. The science ↓

Watermelon Pickle

Ingredients

1 watermelon rind, cut into 1-inch pieces
½ cup coarse sea salt (formerly 'bay salt')
1 tablespoon powdered alum
2 quarts water (for alum solution)
1 cup sugar (for syrup)
1 quart water (for syrup)
2 cups vinegar
6 cups sugar (for final syrup)
Spices (tied in cheesecloth)

Directions

Prepare the rind

Soak the watermelon rind in a weak brine overnight.
Rinse the rind well.
Drop the rind into strong boiling alum water (1 tablespoon alum to 2 quarts water).
Let it stand for 15 minutes.
Drop the rind into ice water until cold.

Make the syrup

Make a syrup by boiling 1 cup sugar with 1 quart water.
Drop the melon into the boiling syrup.
Simmer for 6 to 8 hours.
Pour off the syrup.
Drop the melon into a new syrup made of 2 cups vinegar and 6 cups sugar.
Add the tied spices.
Boil thoroughly.
Let the mixture sit overnight in the syrup.

Jar and seal

Fill jars with the melon.
Pour the boiling syrup over it.
Seal the jars.

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 + syruptop 6% of all pairs

Smell alikestrong

Cooked together5,842 recipes

Shared aroma: ethanol (alcoholic, ethereal).
Sugar + vinegartop 15% of all pairs

Smell alikemoderate

Cooked together20,806 recipes

Shared aroma: beta-damascenone (apple, rose).
Syrup + vinegartop 29% of all pairs

Smell alikelow

Cooked together385 recipes

Shared aroma: ethanol (alcoholic, ethereal).

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

What each ingredient does

Watermelon rind: Forms the pickle itself, becoming tender and absorbing the sweet-sour syrup as it cooks.
Powdered alum: Firms the rind so it stays crisp rather than turning soft during long simmering.
Sugar: Sweetens the pickle and, at high concentration, helps preserve the melon.
Vinegar: Adds acidity that gives the pickle its sour bite and helps preserve it.
Coarse sea salt: Draws water out of the rind during the initial overnight brine, firming its texture.

The step that matters

Simmer for 6 to 8 hours. Long simmering softens the rind enough to absorb syrup. Too little time leaves it tough, while overcooking can make it mushy. Keeping the rind firm depends on the alum treatment done before.

“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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Watermelon Pickle