No, I sometimes mash for several hours. All it means is that you'll get great efficiency...although you don't want to lose TOO MUCH heat. I figure as long as it doesn't fall below 140°F in the time it takes me to go out for dinner and drinks, then I'm fine
A long sparge COULD extract tannins, as it could leave the temperature too high for too long. Temperature is more important, tho. Once you've killed those enzymes (at about 162°F) there is no more conversion taking place and if you go much further above that (the consensus is 170°F, tops) for a long period, then there could be a problem. Think of it like leaving your tea bag in the hot water for too long and it becomes astringent.
I did a SMaSH recently that tastes somewhat astringent and the only thing I can think of was that it had a long, hot sparge. That being said, I wouldn't worry about it much...just err on the side of caution.
How was your efficiency?
A long sparge COULD extract tannins, as it could leave the temperature too high for too long. Temperature is more important, tho. Once you've killed those enzymes (at about 162°F) there is no more conversion taking place and if you go much further above that (the consensus is 170°F, tops) for a long period, then there could be a problem. Think of it like leaving your tea bag in the hot water for too long and it becomes astringent.
I did a SMaSH recently that tastes somewhat astringent and the only thing I can think of was that it had a long, hot sparge. That being said, I wouldn't worry about it much...just err on the side of caution.
How was your efficiency?