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KitchenMath.io

Methodology

How we source density values, what we do when sources disagree, and how often we update.

Primary sources, in priority order

  1. King Arthur Baking Company ingredient weight chart. Authoritative for baking ingredients. Updated periodically. Cited on every applicable ingredient page with a direct link.
  2. USDA FoodData Central. Free public database. Density back-computed from "Cup, NFS" entries against gram weights. Cited on dairy, fat, sweetener, and produce pages.
  3. Cook's Illustrated and America's Test Kitchen for ingredients where laboratory testing has produced specific published values.
  4. Manufacturer packaging (Bob's Red Mill, Morton, Diamond Crystal, Domino) as confirmation data points and for brand-specific values.

Two-source verification

Every published density value on this site has at least two independent source citations. The frontmatter of every ingredient file lists the primary source and at least one secondary source, both with URLs. If the two sources disagree by more than ten percent, we document the disagreement on the ingredient page itself, including which source is used as the calculator default and why.

When sources disagree

Disagreement is common in baking. King Arthur publishes 120 grams per US cup for all-purpose flour. USDA publishes 125. Bob's Red Mill prints 130 on the package. Cook's Illustrated tested at 142 with the scoop method and 113 with the sift method. The right answer depends on which technique the recipe author had in mind.

We default to the value that gives the cleanest match against the most commonly cited per-cup figure for the standard measurement technique. We document the spread in the expert notes on each page. We do not invent a synthetic value when sources disagree.

Update cadence

Density values are reviewed quarterly against primary sources. The lastUpdated date in each ingredient frontmatter reflects the most recent review. If a primary source revises a published value, the affected ingredient page is updated and the lastUpdated date is bumped.

What we do not do

  • We do not scrape competitor conversion sites to populate density values.
  • We do not use the generic 240 gram per cup figure for solid ingredients.
  • We do not invent values when sources disagree. We show the range and explain.
  • We do not use AI to generate density numbers. AI is used only to draft expert content under the densities, which is then reviewed and edited.

Corrections

If you spot a density value that does not match a primary source, or have access to a more authoritative reference, we want to know. The corrections inbox is on the about page.