Why it works: Lemon and butter are a kitchen classic. They rank in the top 16% of all ingredient pairs, and cooks put them together in 41,227 recipes. Both carry 3-hexenal, which smells apple, fruity. The science ↓
Barley-sugar
Ingredients
Directions
Make the syrup
Combine the sugar and spring water in a large pot.
Add enough egg whites to clarify the mixture.
Heat until the mixture begins to whiten and thicken.
Stir in the lemon juice and boil quickly until it reaches the desired consistency.
Optionally, add a few drops of lemon essence just before removing from heat.
Pour and shape
Pour the mixture onto a lightly oiled marble slab or shallow dish.
Once it starts to harden at the edges, shape it into sticks, lozenges, or balls.
If it cools too quickly, place the vessel in a pan of water and gently reheat to liquefy.
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.
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Lemon + buttertop 16% of all pairsSmell alikemoderateCooked together41,227 recipes
Shared aroma: 3-hexenal (apple, fruity).
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Egg + buttertop 17% of all pairsSmell alikemoderateCooked together118,967 recipes
Shared aroma: decanal (soap, orange peel).
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Sugar + buttertop 17% of all pairsSmell alikemoderateCooked together98,233 recipes
Shared aroma: guaiacol (smoky, sweet).
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Sugar + lemontop 18% of all pairsSmell alikelowCooked together53,532 recipes
Shared aroma: 2-nonenal (fatty, green).
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Egg + lemontop 19% of all pairsSmell alikelowCooked together44,316 recipes
Shared aroma: (e,e)-2,4-decadienal (fatty, deep fried).
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
- Forms the glassy, hard candy structure as it cooks and sets.
- Egg whites
- Clarify the syrup, collecting impurities so the candy turns out clear.
- Lemon juice
- Adds acidity that brightens flavour and helps limit sugar crystallisation.
The step that matters
Boiling to the desired consistency. Boiling sugar syrup to the right temperature sets how hard the candy becomes once cooled. Too little cooking leaves it sticky, while overcooking makes it brittle or lets it darken.
Swap the lemon
The recipe marks lemon as optional. How well each one fits the dish's main ingredients (sugar, egg, butter):
- Vanillafits better
- Lemonthe original
- Raisinfits about as well
- Figfits about as well
Fit is the average pairing score against sugar, egg, butter. 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.
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