Brew day no-no?

[paanderson86]

After completing the mash or specialty grains, is it a no-no to squeeze the grain bag a little to get the fluids out? Should I just let gravity do its thing and drain it, then leave it be?

 

[Dozer71]

Squeeze as hard as you like. Most people I know that do BIAB give their bag a good squeezing.

 

[shelbymedic]

Isn't there the risk of tannin release?

 

[soccerdad]

I would modify Dozer's comment slightly:
1) I have no prob squeezing a BIAB bag that has mashed at 150 degrees for an hour
2) I actually used to do the big squeeze .. these days I am more inclined to let it drain
3) I worry (rightfully ?? I dunno) about tannin extraction with a big squeeze on grains steeped to 170 degrees

There is nothing scientific in my thought process, but I have never watered the lawn with BIAB that was undrinkable due to astringency .. I ditched two batches of extract with steeping grains due to astringency. Both stouts. There may have been another factor altogether that brought astringency to those batches, but that is a variable that I was able to identify. YMMV

 

[ziggurat]

Squeezing shouldn't be a problem, at least in my experience. I have been doing small one gallon BIAB batches regularly since April, and I haven't noticed any astringency in my brews. Almost every batch has included a mash out of 10 minutes around 168 degrees.

Wringing out the grain bag definitely helps my efficiency. I would recommend trying the technique out.

As soccerdad said, YMMV, particularly if the grain bill includes darker malts. I've been brewing base malt SMaSHs, blonde, and pale ales to work on my brewing methods, so I might have been lucky so far.

 

[dstockwell]

Yes squeeze....

 

[enkamania]

I put a refrigerator shelf over the pot and push down with a pot to squeeze

 

[csurowiec]

To quote someone else on this site whose name I don't remember at the moment, "squeeze it like it owes you money "

 

[singybrue]

Isn't there the risk of tannin release?

Not from squeezing. Tannins are a result of high temperature and pH.
Squeezing may make the wort a little cloudy, but that will all drop out after fermentation.

Go ahead and squeeze your sack to get the fluids out!

 

[GHBWNY]

Isn't there the risk of tannin release?

Tannins are extracted from the malt during the boil. They are not "hiding" in the grain and released when squeezing the bag. Squeeze or not, tannins in your beer are not a result of it.

 

[day_trippr]

Tannins are extracted from the malt during the boil.[...]

Wait!

Ok. Proceed...

 

[BlueHouseBrewhaus]

The main concern for extracting tannins is during a sparge. In sparging, my understanding is that three conditions must be present to extract tannins - 1) pH >6, 2) temp >170F, 3) runnings gravity <1.010. Squeezing a bag could be considered a kind of sparge since you are pushing additional wort out of the grain. Whether or not that is an accurate characterization, I'm not sure. It seems not since you're squeezing wort out, not adding new fresh water to rinse the grains.

However, even if it could be considered a sort of sparge, it would be highly unlikely that the three conditions above would be met. The temp of the wort you squeeze out will be about the same as your mash temp (i.e. <170). The pH will be pretty much the same as your mash (i.e. <6). As for gravity, I've measured the gravity of the "squeezings" and they have always been well above 1.010.

In other words, squeeze it until it begs for mercy.

 

[seabass07]

Don't squeeze the sack too hard. It's tender.