I frequently see recipes with a variety of malt, usually as each contributes a desirable element (body, head retention, etc.) but not so much with different grain types. The reason for my question: I have this canister of organic multi-grain cereal that is made up entirely of rolled rye, barley, oats and wheat. Was going to toss it all into the mash, but didn't know if there are any conflicts.
(honestly, I'm never going to eat it otherwise)