i have read that it was common for people to drink a grainy, low-alcohol beer throughout the day, even with breakfast. if this is true, does that mean many people were just walking around partially buzzed?
Unfortunately, OP, that's a very common myth about Medieval Europe, and it's exactly that myth which it is my life's work to kill. (Hence the flair.)
But no, it's not true. See here for the complete breakdown.