You need to either create a slurry in a cold liquid, which also works with cornstarch, or you've got to do your gravy in a very wide pan and kind of scatter the flour over the top and then very quickly whisk it in.
Alton BrownI kept thinking, 'Somebody has to make a food show that is actually educational and entertaining at the same time... a show that got down to the 'why things happen.' Plus, I hated my job - I didn't think it was very worthwhile
Alton Brown