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Dessert

Rock Sugar

A hard candy made by boiling clarified sugar and adding powdered sugar and optional colorants.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 7 ingredients
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Why it works: Sugar and egg are a kitchen classic. They rank in the top 21% of all ingredient pairs, and cooks put them together in 122,807 recipes. Both carry 2-nonenal, which smells fatty, green. The science ↓

Rock Sugar

Ingredients

Directions

Prepare the mixture

  1. In a large sugar pan, heat ½ pint of clarified sugar over the fire.

  2. In a small saucepan, beat a small amount of egg white with a fork.

  3. Gradually add fine powdered sugar until it reaches the thickness of cake icing.

Cook and set

  1. Once the sugar has boiled to caramel height, remove it from the heat.

  2. Quickly stir in a tablespoon of the icing mixture and let it rise twice.

  3. Pour the mixture into a sieve or paper case and cover until it sets.

Color

  1. For colored sugar, add carmine, powdered blue, or saffron as desired.

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.

  1. Sugar + eggtop 21% of all pairs
    Smell alikemoderate
    Cooked together122,807 recipes

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

  2. Sugar + saffrontop 30% of all pairs
    Smell alikelow
    Cooked together650 recipes

    Shared aroma: 1-penten-3-one (fish, pungent).

  3. Egg + saffrontop 32% of all pairs
    Smell alikelow
    Cooked together535 recipes

    Shared aroma: nonanal (fat, citrus).

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

What each ingredient does

Clarified sugar
Forms the crystalline body of the candy as it cools and sets.
Fine powdered sugar
Thickens the mixture to an icing consistency, giving fine crystals to form around.

The step that matters

Removing the sugar from the heat at caramel height. Sugar must reach the right temperature to set firmly when cooled. Removing it too early leaves the candy soft, while letting it cook longer turns it darker and more brittle, changing both texture and flavor.

Swap the saffron

How well each one fits the dish's main ingredients (sugar, egg):

  1. Cinnamonfits better
  2. Nutmegfits better
  3. Gingerfits better
  4. Saffronthe original

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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