Heavy cream: why 227 g per cup is wrong
King Arthur Baking publishes 227 g per US cup of heavy cream. This site rejects that figure and publishes 238 g instead, from USDA FoodData Central (density 1.006 g/mL, matching the composition of the substance). The reason:
0.9595 g/ml is below water density and below what any of the three cream products in this row can physically be. Half and half is roughly 10-18% milkfat and sits around 1.02 g/ml. Light cream is 18-30% and sits around 1.01 g/ml. Heavy whipping cream at the FDA minimum 36% sits at USDA's 1.006. All three are denser than water because their aqueous phase carries dissolved milk solids. The same weight assigned to three products with substantially different fat contents cannot be a bench measurement of any of them; it is the volume of a US cup expressed in fluid ounces read as a weight, the same convention that produced the rejected King Arthur figures for milk and yogurt.
The arithmetic
| Source | 1 cup | Density | Status |
|---|---|---|---|
| King Arthur Baking | 227 g | 0.9595 g/mL | Rejected on physics |
| USDA FoodData Central | 238 g | 1.006 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 heavy cream, 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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