While cakes CAN be used as spawn it is typically frowned upon since most folks use spores with brf which can contain contaminants. The preferred practice for bulk would be agar work in order to ensure your spawn (grains) is clean. From my experience cakes

I have 12 brf cakes in pint-sized wide-mouthed jars that are all 3/4 the way colonized and have been consolidated in the middle for a week now. Now I see the reason why half-pint wide-mouthed jars are the best due to the space and length of time for brf c

How I spawn brf to bulk is pretty simple given you have basic knowledge of what we're doing here.The amounts and containers will change,but the procedure is the same. Here's how I like to spawn my brf to bulk,shoebox style! First I gather and prep