Malted grains leftover following brewing mash
Drying time may vary depending on your environment or oven. Your barley is dry when you feel absolutely no moisture remaining.
Alternately, a food dehydrator works as well.
Set your oven to the lowest setting possible. For most ovens this is 75–90°C.
Spread out your grain on a clean, ungreased sheet pan in a thin 5mm layer.
Place in oven and let dry for approximately 7 hours.
4 hours into drying, pull out barley and toss to mix with a spoon.
Using a coffee or spice grinder, process dried spent grain until it becomes a fine flour.
Store your spent grain flour in an airtight jar or plastic container in your pantry.