To Sqeeze Or Not To Squeeze?

[ginsoakedstranger]

Hi all, I'm looking at doing my first BIAB and have a question about the the mash. Found some great info here on BIAB techniques, but am perplexed by one of the steps. In most of the stuff I've read it's suggested to sqeeze the grain bag and add the excess back to the wort after mashing. However when I was researching before doing my partial-extract brews, most people advised against squeezing the grain bag, as this might release some tannins and other undesirables. Is there a reason why this isn't a problem in the BIAB method or is the whole bag squeezing thing just a myth?

 

[katzke]

Wort pH is the single biggest factor to extracting tannins. Dont squeeze the bag all got started by some expert that wrote a book and every other beer author has quoted it as fact. We are lucky in part because this bit of bad info has no negative impact on brewing.

 

[Scruffy]

yup, pH and temperature.

pH 5.2/5.4 and mash/steep on the low side (in my case i'm at 64C a lot...).

in a traditional all grain homebrew mash, the water to grain ratio is much lower than a BIAB. I reckon for the better - although with less grain per litre, getting the malt to lower the pH needs an occasional nudge (using gypsum or other salts is a bit difficult to master at these ratios, much better the proprietary '5.2'... or lactic or phosphoric acid @ your local sponsor)

each system (and each brewer) is slightly different and results will vary. In the past I've mashed at a higher temp (from 66C up to 72C) with the result less fermentable sugars, so sweeter brews - no tannins in the stewed tea sense... but a slight harshness. I reckon a lot of people use the strained tea bag as an analogy but this is daft, all beer contains tannins, some cause a bit of astringency true, but some contribute to haze an stuff...

 

[Bribie G]

I squeeze like buggery. Some commercial mega breweries (UK particularly) use huge hydraulic presses something like a cider press but rotated onto its side to get the last possible drop.

 

[whitegoose]

I squeeze like buggery. Some commercial mega breweries (UK particularly) use huge hydraulic presses something like a cider press but rotated onto its side to get the last possible drop.

Commercial mega breweries brew BIAB?

 

[Bribie G]

Commercial mega breweries brew BIAB?

Yes - edit, just need a bloody big crane.

Actually they are almost BIAB in that they put the mash into big baggy things which get pressed. I had a diagram on my late computer and can't find it again but it looks something like:



Where the mash is in the brown bags and the blue bags are big rubber thingos that expand and press the shyte out of the brown bags. Then after they have collected the wort they open the brown bags at the bottom and the grain falls out and gets sent off to feed cows whatever. I expect Beerbelly could knock you up a home version for a few grand

 

[felten]

and that is how you get the delicate taste of a VB!

 

[joecast]

another squeezer here. get all that sweet wort out of the grain for the boil baby!

 

[argon]

I used to squeeze used to beat the thing like it owed me money. Never noted any tannin extraction Cause Im a massive tightarse when it comes to brewing and extracting all I can from my batches. But I dont reckon its physically possible by hand to extract tannins form BIAB through squeezing.

Last few brews I havent bothered giving it more than enough so it doesnt drip too much when I move it to sit it in my 19L pot on top of the cake rack. It usually just drips out another couple of litres which is the same amount I would get if I squeezed the bejesus out of it. The only reason I see for the recommendation to squeeze the bag is to get that little extra wort out and grab a couple of efficiency points. For me if I can achieve the same thing by just letting it drip, Im happy and dont bust my arse trying to suspend and squeeze out 9kg of wet grain.

The single biggest jump in efficiency I have noted is in adjusting my ph. I got some of that 5.2 stuff and add that to my strike water. Also in the case of a couple of hoppy ales I did recently added a little Gypsum to the boil as well. Essentially my efficiency jumped from 70% to 79% into kettle without changing a single other thing. And thats with double batches too. Which for BIAB, tend to be less efficient.

 

[under]

I squeeze. But dont go over the top. Then just let it hang over a bucket and dump the dripping into the boil. Seems to be working for me.

 

[Thirsty Boy]

and that is how you get the delicate taste of a VB!

As a matter of fact - that's how you get the often highly approved of taste of Coopers.

Coopers uses a Mash Filter, and that's what Bribie is talking about. Mash filters aren't a type of BIAB... but in a very basic sort of way.. BIAB is a type of mash filter.

Squeeze -- give it a moderate squeeze and you will be fine... no need to go nuts and short of putting it in a press, you probably couldn't go far enough to be a massive problem anyway.

 

[Nick JD]

I reckon the worst part of squeezing the bag would be the HSA activity goings on. Sounds like an 80 year old Nana on the loo after she's had eighteen sherrys.

 

[Bribie G]

Thanks TB, Mash Filter is what I couldn't remember.

Here's the PDF you posted a few years ago, awesome piece of equipment

 

[ginsoakedstranger]

Awesome! Thanks guys...looks like this one's totally busted. To think of all the extra goodness my brews have been missing out on, oh well, no more. It's going to be great to experiment with small AG batchs to get my head around the techniques and how to have greater control over the flavour. Extra considerations like Ph levels adding gypsum and the like got me thinking. Cheers again