Buttermilk Powder

One US cup of buttermilk powder weighs 120 grams (4.2 ounces). Going the other way, 100 grams is about 0.83 cups.

Also called dried buttermilk, dry buttermilk, powdered buttermilk, buttermilk powder dried, sweet cream buttermilk powder, cultured buttermilk powder.

Buttermilk powder weighs 120 g per US cup (4.2 oz), 30 g per quarter cup and 15 g per 2 tablespoons. USDA, King Arthur's own Dried Buttermilk Powder package, NOW Foods and Bob's Red Mill all give exactly that density. King Arthur's chart, at 18 g per 2 tablespoons (144 g per cup), contradicts King Arthur's own label and is rejected.

Buttermilk powder is buttermilk with the water taken out: the liquid left after cream is churned into butter, dried to a fine powder. NOW and Bob's Red Mill sell it as sweet cream buttermilk powder, and King Arthur's ingredient list reads simply "buttermilk". USDA puts it at 3% water, 49% lactose, 34% protein, 8% minerals and 6% fat. Bakers keep it for pancakes, biscuits, scones, breads and ranch-style seasoning: the powder goes in with the dry ingredients and the water with the wet. King Arthur's directions reconstitute it at 1 part powder to 4 parts water.

USDA SR Legacy "Milk, buttermilk, dried" (FDC 171274) lists 1 cup at 120 g and 1/4 cup at 30 g. King Arthur's Dried Buttermilk Powder package gives 1/4 cup at 30 g, NOW Foods' label 1/4 cup at 30 g, and Bob's Red Mill's 2 tablespoons at 15 g: all four are 120 g per cup. USDA's own tablespoon, 6.5 g, scales to only 104 g per cup, a reminder that a level tablespoon of fine powder rarely scales up exactly. A few smaller brands, as transcribed by the recipe-costing site ReciPal, label heavier: Anthony's and Hoosier Hill at 8 g per tablespoon (128 g per cup) and Judee's at 18 g per 2 tablespoons (144 g). Saco's Cultured Buttermilk Blend is a different product, churned buttermilk blended with sweet whey and lactic acid; its can serves 4 tablespoons, retailers list that serving at 23 g, about 92 g per cup, so follow its own label.

The physical check compares the figure with what the powder is made of. From USDA's composition, the solid powder with no air in it is about 1.43 g/mL, so a cup at 120 g is about a third powder and two thirds air, which is how a fine, dry powder behaves when spooned. The other non-instant dairy powders on this site agree: non-instant nonfat dry milk weighs 112 to 148 g per cup and whole milk powder 100 to 120 g. King Arthur's 144 g would be a cup packed a fifth tighter, the weight of a cup scooped from the bag or tapped down rather than spooned.

King Arthur's chart lists buttermilk powder at 2 tablespoons = 2/3 oz = 18 g, 144 g per cup. King Arthur's own package for its dried buttermilk says 1/4 cup is 30 g, which is 15 g per 2 tablespoons. The chart and the label cannot both be right, and USDA, NOW and Bob's Red Mill side with the label. The chart figure is recorded as a rejected source with its own correction page.

Practical guidance: 1 tablespoon is 7.5 g, 2 tablespoons 15 g, 1/4 cup 30 g and 1/3 cup 40 g. To replace 1 cup of liquid buttermilk, King Arthur's 1-to-4 ratio works out to 1/4 cup of powder (30 g) and 1 cup of water. Opened powder takes up moisture and forms lumps; keep it tightly closed and break up lumps before measuring, since a lumpy cup packs unevenly. Spoon the powder into the cup and level it rather than scooping.

The following published figures for buttermilk powder are rejected here, with the physics or standards reasoning behind each rejection on its own page:

• King Arthur Baking Ingredient Weight Chart: 144 g per cup