Lemon Curd: why 227 g per cup is wrong
King Arthur Baking Ingredient Weight Chart publishes 227 g (8 oz) per US cup of lemon curd. This site rejects that figure and publishes 320 g (11.3 oz) instead, from Bonne Maman Lemon Curd (producer label) (density 1.3526 g/mL, matching the composition of the substance). The reason:
0.959 g/mL is lighter than water, but lemon curd is about half sugar, cooked with lemon juice, egg and butter; even the butteriest jarred curd (13% fat, 54% sugars) works out from its composition to about 1.26 g/mL, and the labels give 1.35. Half a cup is 4 fluid ounces, and 113 g is 4 weight ounces: the fluid ounce read as a weight ounce, King Arthur's 227 g cup.
The arithmetic
| Source | 1 cup | Density | Status |
|---|---|---|---|
| King Arthur Baking Ingredient Weight Chart | 227 g8 oz | 0.9595 g/mL | Rejected on physics |
| Bonne Maman Lemon Curd (producer label) | 320 g11.3 oz | 1.3526 g/mL | Published here |
The 227-gram pattern
The figure 227 is 8 × 28.35 — the conversion for weight ounces (avoirdupois). It is applied to volume in fluid ounces without going through the substance’s density. For a substance that happens to have a density of about 0.96 g/mL, the answer would be right; for water, milk, yogurt, cream, buttermilk, pumpkin purée, ricotta and evaporated milk, all of which are denser than water, it is wrong. The same number 227 appears on the King Arthur chart for every one of these ingredients, which is the signature of an arithmetic pattern rather than a measurement.
The full list of 227-gram rejections is on the corrections page.
The published figure and its sources
The full sourcing for lemon curd, including every accepted and rejected figure, the state or filling method behind each, and the physics or standards reasoning applied, is on the ingredient page.
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