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 ↓
Boston Cream
Ingredients
Directions
Make the syrup
Boil the sugar and water together for 15 minutes.
Beat the egg whites until well combined.
Once the sugar and water mixture is cool, mix in the egg whites, tartaric acid, and essence of lemon.
Let the mixture cool, then bottle for use.
Make the drink
For a drink, pour ⅓ cup of the mixture into a tumbler and fill it three-quarters full with water.
Add enough carbonate of soda to cover a sixpence and stir quickly until a cream-like foam forms on top.
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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Sugar + lemontop 18% of all pairsSmell alikelowCooked together53,532 recipes
Shared aroma: 2-nonenal (fatty, green).
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Lemon + eggtop 19% of all pairsSmell alikelowCooked together44,316 recipes
Shared aroma: (e,e)-2,4-decadienal (fatty, deep fried).
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Sugar + eggtop 21% of all pairsSmell alikemoderateCooked together122,807 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
- Sugar
- Dissolves into the syrup to provide sweetness and body.
- Egg whites
- Trap air and add foam and a light, creamy texture.
- Tartaric acid
- Provides sourness and reacts with the carbonate to release bubbles.
- Carbonate of soda
- Reacts with the acid to release carbon dioxide, creating fizz and foam.
- Essence of lemon
- Adds a bright lemon aroma and flavour.
The step that matters
Stirring quickly after adding the carbonate of soda. The carbonate reacts with the tartaric acid to release carbon dioxide almost immediately. Stirring quickly spreads the gas through the liquid and helps the foam form before the bubbles escape.
Swap the lemon
How well each one fits the dish's main ingredients (sugar, egg):
- Vanillafits better
- Raisinfits about as well
- Lemonthe original
- Datesfits less well
Fit is the average pairing score against sugar, egg. 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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