For barley and oats that temp would be ok, they're both fairly easy to get them to gel. I don't know about wheat, haven't used any except malted. With corn it's really tough, ya pretty much have to boil it for a good while, or use steam injection, at least 30-45 minutes, often longer, to get the starch to gel out.
"Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves." William Pitt