Spent grains are malted barley grains used in the early stages of making beer – like when making tea, the barley grains are steeped in heated water that releases enzymes that breaks down the starch in the grain into sugars.

The water (now referred to as wort) is extracted leaving behind the barley grains (aka spent grains or tea leaves in our analogy)

Note – there are no hops included in the spent grains at this point.

Malted Barley Flour – When you read “malted barley” in most recipes it’s typically a powdered malt extract derived from barley, as opposed to just finely ground malted barley. It acts as an auxiliary source of fuel for yeast in long-fermented doughs (both naturally and chemically leavened) and/or as a way of sustaining robust fermentation when the natural amylase levels in the flour are low.It has no nutritional value to the consumer

Spent barley grains vs malted barley flour / powder

Generally, spent grains have different properties to malted barley flour:

Spent grains would have very little sugar/starch available and significantly more fibre and protein.

The malted barley flour would have very little fibre typically having had the husk sifted out.

In a scenario where the malt flour is being used for it’s enzymatic activity the spent grain wouldn’t provide the desired results, the enzymes having already been used/denatured in the brewing process.

It’s also common to use malt barley flour in sweeter bread products like doughnuts, cakes etc. The concern here would be that spent grain won’t provide the sweetness desired, the starch/solvable sugars already having been extracted in the brew house.

Summary: Malted flour has simple sugars; spent grains have less; more fibre + less of ecological footprint

When to consider using spent barley grains

The wet unprocessed spent barley grain does boost fermentation as well, but it does so by accelerating enzymatic activity, not by feeding the yeast spores directly. Spent grains often requires an adjustment to either the recipe and/or the method in larger quantities, the malted barley powder typically doesn’t. The spent grain also has a more distinct flavour.

This post was complied through research and through conversations with subject matter experts. A big thank you to:

Devin from Barn Owl Malt. If looking for malted barley on Ontario for use in brewing process, please visit Barn Owl Malt

For locally grown Ontario artisan flours, say hi to Mark Hayhoe at K2 Milling

Jonathan Biro, Head Baker, Drake Commissary

Can you replace malt barley grain flour with spent grains?