« on: July 27, 2016, 07:15:24 AM »
I think the "tannins" thing is a bit of a crock. However squeezing can indeed cause starch haze in the final beer if your mash hasn't fully converted.
Personally I incorporate a dunk sparge for improved efficiency. And I always, always, always add every single drop from the draining of the bag. Without any squeezing required. Often times 30 or 45 minutes into the boil, I am still finding a cup or two of wort below the grain bag and I simply add it to the boil. This will maximize efficiency. Alternatively, sometimes I have saved the extra wort for making yeast starters, which is a great purpose for it as well but sacrifices 1 or 2 points of efficiency.
Caveat: Efficiency really isn't all THAT important anyway. Consistency is way more important. If you can skip a sparge or do a sloppy sparge and still get more than 70% efficiency on a consistent basis, then you've already won, keep on doing what you're doing.
I really am not a big advocate for squeezing the bag though. It just isn't necessary. Get yourself a colander and let gravity do all the work for you. Then there's negligible chance for squeezing anything weird out of the grains, whether that's starch or tannins or anything else.
Great questions. Cheers.