I'm planning on doing a 2.5 gallon brew of oatmeal stout with a coopers Irish stout and 500 grams of dme. Just wondering if anyone can help me on how much oatmeal to use? Thanks
Consider toasting it on a cookie sheet in the oven at 300* for 30-45 mins beforehand to bring out the oatmeal flavor. Once you really start to smell the oats, they're done and ready for the brew.
I'm using flaked/rolled oats as they have their starches pre-gelatinized and don't really require cooking. I'd stay away from steel cut oats that do require cooking.
Oats, however, do not have the enzymes to self-convert and you must do a mini-mash with say a pound of 2-row malt. Otherwise you'll end up with unconverted oatmeal starches in your beer and that is not a good thing.