is there such a thing as to much grains in a batch? i am an extract brewer right now. was just curious the affect of say steeping 3, 4 or 5 lbs of grains for a 2-3 gallon extract boil?
As far as specialty grains, there is never any need to have 5 lbs in a 5 gallon batch. You'd have a huge muddening of flavors and it wouldn't work too well for you. You can though go for a partial mash.
Yeah, that would be entering the partial mash realm with that much grain. Being an extract brewer, you typically won't steep more than 2# of grain, and that is pushing it.
The main thing you get from steeping grains is color and the proteins that aid in head retention. I often use a half pound and never more than a pound with good results.
If those specialty grains are Crystal malts, you'd have an awfully sweet beer at 3-5 lbs. If they're base grains (such as 2-row) that's fine in that quantity, but you'd need to do a proper mash, not a steep.
You can quickly see what the addition of specialty grains will do to the color of your beer.
Next, make a stop at http://www.brewsupplies.com/grain_profiles.htm to see what each type of specialty grain adds to the flavor. With these 2 pieces of information, you will have a better understanding of what to add and why.