Diastatic Malt Powder

One US cup of diastatic malt powder weighs between 85 and 168 grams, depending on how the cup is filled and which source measured it. That range is the answer; a single number would not be. Every figure behind it is below, with the method each source used.

Also called diastatic malt, malted barley flour, diastatic barley malt, active malt powder, sprouted barley flour, enzyme active malt.

TL;DR: Diastatic malt powder ranges 96-168 g/cup depending on composition. Pure malted barley flour products (King Arthur, Modern Mountain, Bakers Club) sit near 96 g/cup, while blends with dextrose and wheat flour (Red Star, Kalustyan's) pack denser at 140-170 g/cup. Used in bread baking as an enzyme booster, not a sweetener.

Diastatic malt powder is finely ground sprouted barley that retains the amylase enzymes generated during germination. Those enzymes break flour starch into simple sugars, feeding yeast and improving crust color and rise. The typical dose is tiny — 0.5% to 2% of total flour weight, roughly 1/2 to 1 teaspoon per 3 cups of flour — because too much creates gummy, over-browned crumb. Common uses: bagels (dough and boiling water), pretzels, long-fermented sourdoughs, artisan breads made with organic or whole-wheat flour that doesn't already contain added barley malt, and pizza doughs where extended cold fermentation would otherwise deplete available sugars.

Cup weight varies substantially based on composition. King Arthur's Diastatic Malt Powder is 100% malted barley flour with no additives; their nutrition label lists 1 teaspoon = 2g, giving 96 g/cup. Modern Mountain Baking Company's version is also 100% malted barley flour, similar density. Blended products like Red Star Diastatic Malt (malted barley flour + wheat flour + dextrose) and Kalustyan's diastatic malt (same ingredient set) pack denser because the added dextrose is a fine crystalline sugar that fills gaps between flour particles. Bakers who measure by level scoop report cup weights up to 168 g/cup for blended products, a 75% variance from King Arthur's pure figure.

Physical density comparison: pure malted barley flour behaves like regular barley flour, which King Arthur lists at 85 g/cup. The 96 g/cup King Arthur figure for diastatic malt is 13% higher than plain barley flour, reflecting either the slight density change from sprouting and drying or label rounding of the 1.77g per level teaspoon actual measurement to 2g. Blended products with dextrose (which alone packs at roughly 200 g/cup as a fine crystal) can push density much higher depending on blend ratio.

Substitution equivalence with barley malt syrup: King Arthur publishes 0.8g diastatic malt powder per 1g barley malt syrup. That means for a recipe calling for 1 tablespoon barley malt syrup (21g), substitute roughly 17g diastatic malt powder (about 2 teaspoons of a pure-barley-flour product like King Arthur's). The math accounts for the malt syrup's higher moisture content and the concentrated enzyme activity in the dried powder. Diastatic malt powder is enzymatically active in ways barley malt syrup is not once heated, so use with caution — start at 0.1-0.2% flour weight and work up.

Distinct from non-diastatic malt powder: the two products look similar but function differently. Non-diastatic malt powder (King Arthur lists at 144 g/cup) has had its enzymes deactivated by heat during production. It provides sweetness, flavor, and browning to baked goods but does not accelerate fermentation. Diastatic malt provides enzyme activity for improved rise; non-diastatic provides flavor and color only. Bakers should never assume interchangeability — a recipe calling for diastatic malt will fall flat if non-diastatic is substituted (the enzyme boost is lost), while over-dosed diastatic can turn a non-diastatic recipe into a gummy over-browned mess.

Distinct from malted milk powder: malted milk powder contains dry milk solids, sugar, and malt extract, a completely different product intended for chocolate malt beverages and malt balls. Not a substitute for either diastatic or non-diastatic malt powder in bread applications. King Arthur lists malted milk powder at 140 g/cup — coincidentally similar to non-diastatic malt powder by weight but with completely different functional behavior.

Practical baker recommendation: for any recipe calling for diastatic malt by teaspoon or tablespoon volume, weight is the reliable measure — dose 0.5% to 1% of flour weight for most bread applications, up to 2% for the strongest fermentation boost. Start conservatively; excess diastatic malt turns crumb gummy and crust overly dark. Check the ingredient list on your product: pure malted barley flour products deliver the strongest enzyme activity per gram, while blends are diluted with dextrose or wheat flour and require slightly higher doses to achieve equivalent enzyme activity.