Name: Peanut Brittle
Ingredients: 1½ cups sugar; ½ cup water; ⅓ cup glucose (pure corn syrup); 2 tablespoons butter; ½ pound raw shelled peanuts; 1 teaspoon vanilla extract; 1 teaspoon baking soda; 1 tablespoon cold water

Why it works: Corn and peanut match in chemistry and in kitchens. They rank in the top 6% of all ingredient pairs, and cooks put them together in 346 recipes. Both carry 2,4-decadienal, which smells seaweed. The science ↓

Peanut Brittle

Ingredients

Directions

Make the syrup

Combine sugar, water, and glucose in a saucepan over medium heat.
Stir until sugar dissolves.
Wash down the sides of the saucepan with a damp cloth.
Cover and boil for 3-4 minutes.
Uncover and cook until the mixture reaches 275°F (135°C).
Test by cooling a small amount; it should cling but not stick to teeth.

Add peanuts and soda

Add butter and peanuts, stirring constantly until peanuts are browned.
Dissolve baking soda in cold water, add vanilla, and stir vigorously into the candy mixture.
Once the candy stops foaming, pour it onto a warm, well-oiled marble surface or platter.

Pull and shape

When edges cool slightly, pull the candy as thin as possible.
Loosen the center with a spatula, flip it over, and pull thin again.

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.

Corn + peanuttop 6% of all pairs

Smell alikestrong

Cooked together346 recipes

Shared aroma: 2,4-decadienal (seaweed).
Sugar + syruptop 6% of all pairs

Smell alikestrong

Cooked together5,842 recipes

Shared aroma: ethanol (alcoholic, ethereal).
Sugar + vanillatop 8% of all pairs

Smell alikelow

Cooked together35,032 recipes

Shared aroma: beta-damascenone (apple, rose).
Corn + vanillatop 9% of all pairs

Smell alikemoderate

Cooked together1,943 recipes

Shared aroma: ethyl cinnamate (sweet, balsamic).
Peanut + vanillatop 10% of all pairs

Smell alikestrong

Cooked together1,176 recipes

Shared aroma: guaiacol (smoky, sweet).

Sugar and vanilla barely smell alike, yet cooks put them together in 35,032 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: Forms the brittle's crisp, hard candy structure as it cooks to temperature.
Glucose (pure corn syrup): Inhibits sugar crystallization, keeping the candy smooth rather than grainy.
Raw shelled peanuts: Provide the nutty body and toasty flavor as they brown in the syrup.
Baking soda: Reacts with the hot syrup to release gas, creating a light, airy, brittle texture.
Butter: Adds richness and a smoother mouthfeel to the candy.

The step that matters

Cooking the syrup to 275°F (135°C). Sugar must reach the correct temperature to set into brittle when cooled. Undercooked syrup stays sticky and soft, while overcooked syrup turns bitter and dark. Stirring the syrup would encourage crystallization.

Swap the peanut

How well each one fits the dish's main ingredients (sugar, corn, syrup, butter, vanilla):

Almondfits better
Chestnutfits better
Hazelnutfits better
Peanutthe original

Fit is the average pairing score against sugar, corn, syrup, butter, vanilla. 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.