To put it simply, grain has carbohydrates that yeast can't eat (un-fermentable).
Grains also have enzymes (enzymes are chemicals that cause reactions to occur).
The enzymes work to convert the un-fermentable carbohydrates into (mostly) fermentable carbohydrates (sugar). This only happens between about 140F and 160F. Above this temperature, the enzymes are destroyed.
So, for brewing, we soak the grains at somewhere between 140F and 160F (called mashing), then drain off as much liquid as we can (or remove the grains from liquid), and boil the remaining liquid with hops in it (called wort). The grains are thrown away.
In your case, you've extracted lots of un-fermentable carbohydrate (starch and others) but haven't converted it to sugar. So you won't get much fermentation or alcohol, and might get an infections from something that can eat starch. If you want to, for sh**s and giggles, you could add a packet of glucoamylase, which is an enzyme that will convert the starch to fermentable sugars. I still doubt it'll lead to good beer though!