Barley Malt Syrup

One US cup of barley malt syrup weighs 336 grams. Going the other way, 100 grams is about 0.30 cups.

Also called barley malt, malt syrup, barley malt extract, traditional barley malt syrup, organic barley malt syrup, non-diastatic malt syrup.

TL;DR: Barley malt syrup consistently weighs 336 g/cup (21g per tablespoon), converging across King Arthur's chart, Eden Foods (the dominant US brand), and USDA branded food data. The naming confusion is where bakers get tripped up: it's a distinct product from barley malt extract powder, diastatic malt, non-diastatic malt powder, and malted milk powder.

Barley malt syrup is a thick, dark, molasses-like sweetener made by extracting maltose and complex carbohydrates from sprouted (malted) barley. Its primary baking uses are bagels (both in the dough and in the boiling water for glossy crust), pretzels (soft or hard), pumpernickel and other dark whole-grain breads, gingerbread, and baked beans. About half as sweet as refined sugar, it contributes a distinctive malty flavor no other sweetener duplicates.

Density is a solved physical property here. Concentrated maltose solutions at the standard 74-79% solids fraction produce a density near 1.42 g/mL, virtually identical to honey. Eden Foods (USDA branded UPC 024182491159, the dominant retail brand and only widely-available producer of barley-malt-only syrup in US supermarkets) publishes 21g per 1 tablespoon on their nutrition label, which works out to 336 g/cup. King Arthur's Ingredient Weight Chart lists barley malt syrup at 42g per 2 tablespoons, the same 336 g/cup. USDA branded food data for the Eden UPC confirms 355 g per metric cup (336 g per US cup). Three independent sources, exact convergence, no correction needed.

The disambiguation matters more than the density. Five related products are frequently confused for one another. Barley malt syrup (this entry) is a thick liquid concentrate at 336 g/cup, non-diastatic, used for sweetness and flavor in bagels and dark breads. Barley malt extract is often used interchangeably with barley malt syrup, but the extract label sometimes covers products containing other grains or corn syrup; home brewers use liquid malt extract (LME) for beer wort at similar density. Non-diastatic malt powder is the dried version of malt syrup with no active enzymes: King Arthur sells it at 18g per 2 tablespoons (144 g/cup), and the substitution equivalence is 1 tablespoon syrup (21g) matches roughly 2 tablespoons powder (16g) by weight solids. Diastatic malt powder retains active amylase enzymes that break down starch, used in tiny quantities (fractions of a teaspoon per loaf) to boost fermentation and browning in long-proofed doughs. Malted milk powder contains dry milk solids and sugar plus malt extract, made for chocolate malt beverages and malt balls: it is not a substitute for barley malt syrup in bread applications, and King Arthur lists it at 35g per 1/4 cup (140 g/cup).

King Arthur also has a separate Malt syrup chart entry at 43g per 2 tablespoons (344 g/cup), a 2% variation from the barley-malt-specific entry that likely reflects blended malt syrups containing non-barley grains.

Practical baker recommendation: for bagels and pretzels, use barley malt syrup by weight (21g per tablespoon in dough, more in the water bath). For any barley-malt-syrup recipe where the product is unavailable, molasses is the closest 1:1 substitute by weight; light brown sugar dissolved in equal weight of water works in a pinch but lacks the malty character. If a recipe calls for barley malt syrup and you only have non-diastatic malt powder, use half the weight of powder (16g powder for every 21g syrup).