Extract twang

Home brewers often complain about 'extract twang' which vaguely describes the telltale off-flavors from extract brewing. It seems the main problem (aside from contamination) is boil size. The typical kit is for 5 gallon batches but the process involves a 3 gallon boil since most homebrewers can't boil much more. There are two negative consequences:

1. The extracts are added to the boil portion and hence saturate it. The hops cannot be as effectively absorbed. This can be avoided, in part, by not adding half of the extracts until the end of the boil (long enough to sanitize)
2. Water needs to be added to the wort in the fermenter to bring it up to full size, rather than being incorporated in the whole boil. If you did this with a curry sauce, I doubt it would be as flavorful.

These contribute to the extract twang. This is where the smaller batches are advantageous: you can do the wort as a full boil.