I have a recipe that calls for 8.5lbs of light LME, I have extra light DME from a previous batch. Will substituting the LME for DME result in any off flavor or color? The batch I wanna make is a Dogfish Head clone 60min IPA.
It might be a *little* lighter, but no big deal. LME tends to be a little bit darker (even "light" LME), but this won't impact flavor. I know DFH 60 isn't a terribly light beer, but presumably you're getting color mostly from whatever specialty grains are called for in the recipe anyway.
As 2nd Street said, it's about a 20% difference. I can't remember if technically you use 20% less DME than LME, or you use 20% more LME than DME (the math works out slightly different when you do the conversion) - in any case, change it by 20% and you're close enough.