果酱糖比例计算器 — 公式

How Jam Sugar Ratios Work

The Standard Ratio

Traditional jam uses a 1:1 ratio of fruit to sugar by weight for high-pectin fruits, or slightly more sugar for low-pectin fruits. Modern recipes often reduce sugar.

Why Sugar Matters

  • Preservation: Sugar at 60%+ concentration inhibits microbial growth.
  • Gel formation: Sugar interacts with pectin and acid to form the gel structure.
  • Flavor: Balances the natural tartness of fruit.

    • Pectin

    High-pectin fruits (apples, citrus) gel easily with less sugar. Low-pectin fruits (strawberries, peaches) may need added pectin or more sugar to set.

    计算示例

    Make jam with 1000 g of medium-pectin berries, standard sweetness.

    1. Base sugar ratio = 0.6 + (1 - 0.75) x 0.3 = 0.6 + 0.075 = 0.675.
    2. Sugar = 1000 x 0.675 x 1 = 675 g.
    3. Lemon juice = 1000 / 500 = 2 tbsp.
    4. Yield = (1000 + 675) x 0.6 = 1005 mL.
    5. Jars = ceil(1005 / 250) = 5 jars (250 mL each).