[mpietropaoli]

Am starting the boil on a BIAB "5 gallon" kolsch. 

10.3 LB Weyermann Pils
.5 LB Wey Vienna

-doughed with 5.4 gal to reach mash temp of 149, 75 minute mash
-raised to mash out of 170 for 10 min
-2 gal of 168* water for a single batch "sparge" (I remove the bag from my kettle and place in an empty fermenter with the sparge water for 10 min, and teabag it a bit :-)....took a brix measurement, got about 1.75 gallons @ 1.018/6 brix from this step)
-I squeeze my brew bag like it owes me money after the sparge, collected 7.25 gallons at 12 brix/1.048 pre-boil, so 348 total gravity points

by my calc, this is somewhere between 87 and 89% efficiency (10.8lb total grist, times maximum yield of 36-37 points per gallon per pound, or 399 gravity points....divide 348/399 = 87%). 

I am considering adding some water volume, but is this possible?  Help!

[cornershot]

Sounds like it's possible. The question is: is it a good idea to squeeze the grain bag to achieve it? I don't have much experience with biag, but i'd say you're extracting significant tannins. If this worked, we'd all have presses built into our mash tuns!

[mpietropaoli]

You know, its interesting, I had originally heard when I first started extract brewing that squeezing the grain/muslin bag is a terrible idea...you should just let it drain.

Then I started BIAB'ing, and have been squeezing the bag like crazy (typically I will spin it around like I'm going to tie it, which extracts more liquid, then I also put it onto a canning rack above my kettle and apply pressure with the kettle lid).  I honestly can't perceive tannins.  I've recently heard that they are more of a result of low mash pH than applying pressure to the husk of the grain to extract liquid.  Makes sense I guess. 

Anyway, looking like I have a little more Kolsch than I planned for with a touch higher gravity.  One of those good problems I guess!

Cheers!

[cornershot]

Ok then, next brew I'm gonna no-sparge. Then i'll use my press to wring out wort for a separate 1 gallon batch. It will double as a hot side aeration experiment!   

[a10t2]

If this worked, we'd all have presses built into our mash tuns!

A lot of breweries do!

[erockrph]

I BIAB/no-sparge. Since I started milling my own grain my kettle efficiency is right at 84-86%, so I'd say this is definitely possible. I've always squeezed the ever-loving snot out of my bag and I've never picked up any astingency in my beers from this. As long as you don't get a lot of husk material passing through your bag I think you'll be fine.

If I had to venture a guess about the old cautions about not squeezing your grain bag, I'd guess that the issue would be husk material getting through the muslin bag into the boil.

[cornershot]

If this worked, we'd all have presses built into our mash tuns!

A lot of breweries do!

Ok now I'm officially interested!  I will get back to trying biag. I will squeeze the bag. Maybe I will build a press onto my mash tun! If I can save time and increase efficiency without sacrificing quality, that's just a no-brainer! In fact, I could use my existing AG system and double my output in roughly the same amount of time! And all I need is a couple of bags! Love it already!

[beersk]

I BIAB/no-sparge. Since I started milling my own grain my kettle efficiency is right at 84-86%, so I'd say this is definitely possible. I've always squeezed the ever-loving snot out of my bag and I've never picked up any astingency in my beers from this. As long as you don't get a lot of husk material passing through your bag I think you'll be fine.

If I had to venture a guess about the old cautions about not squeezing your grain bag, I'd guess that the issue would be husk material getting through the muslin bag into the boil.

Definitely. I brew in a bag as well and squeeze the bag a lot. I get around 78-80% efficiency with my mill gap set at .032". Works out pretty nicely. Wort is maybe a little cloudier, but the beer turns out fine, so no big deal. I've noticed that my beers don't form as big of a krausen on brew in a bag batches though. Kinda strange, but beers haven't had head retention issues.

[denny]

Sounds like it's possible. The question is: is it a good idea to squeeze the grain bag to achieve it? I don't have much experience with biag, but i'd say you're extracting significant tannins. If this worked, we'd all have presses built into our mash tuns!

Some commercial breweries do use presses for the mash.  Can you explain why it would cause tannin extraction?

[denny]

You know, its interesting, I had originally heard when I first started extract brewing that squeezing the grain/muslin bag is a terrible idea...you should just let it drain.

Then I started BIAB'ing, and have been squeezing the bag like crazy (typically I will spin it around like I'm going to tie it, which extracts more liquid, then I also put it onto a canning rack above my kettle and apply pressure with the kettle lid).  I honestly can't perceive tannins.  I've recently heard that they are more of a result of low mash pH than applying pressure to the husk of the grain to extract liquid.  Makes sense I guess. 

Anyway, looking like I have a little more Kolsch than I planned for with a touch higher gravity.  One of those good problems I guess!

Cheers!

Tannins can result from a high mash pH, not low. 

[garc_mall]

You know, its interesting, I had originally heard when I first started extract brewing that squeezing the grain/muslin bag is a terrible idea...you should just let it drain.

Then I started BIAB'ing, and have been squeezing the bag like crazy (typically I will spin it around like I'm going to tie it, which extracts more liquid, then I also put it onto a canning rack above my kettle and apply pressure with the kettle lid).  I honestly can't perceive tannins.  I've recently heard that they are more of a result of low mash pH than applying pressure to the husk of the grain to extract liquid.  Makes sense I guess. 

Anyway, looking like I have a little more Kolsch than I planned for with a touch higher gravity.  One of those good problems I guess!

Cheers!

Tannins can result from a high mash pH, not low.

Denny, You are on it this morning... I am still not caffeinated enough to catch these things...

[cornershot]

Sounds like it's possible. The question is: is it a good idea to squeeze the grain bag to achieve it? I don't have much experience with biag, but i'd say you're extracting significant tannins. If this worked, we'd all have presses built into our mash tuns!

Some commercial breweries do use presses for the mash.  Can you explain why it would cause tannin extraction?

I guess it is something i learned in my early days of extract with specialty grain brewing: don't squeeze the bag. I just carried on and never questioned it. So why don't more homebrewers press out their spent grains?

[denny]

Sounds like it's possible. The question is: is it a good idea to squeeze the grain bag to achieve it? I don't have much experience with biag, but i'd say you're extracting significant tannins. If this worked, we'd all have presses built into our mash tuns!

Some commercial breweries do use presses for the mash.  Can you explain why it would cause tannin extraction?

I guess it is something i learned in my early days of extract with specialty grain brewing: don't squeeze the bag. I just carried on and never questioned it. So why don't more homebrewers press out their spent grains?

Likely because they heard the same thing you did.

[denny]

You know, its interesting, I had originally heard when I first started extract brewing that squeezing the grain/muslin bag is a terrible idea...you should just let it drain.

Then I started BIAB'ing, and have been squeezing the bag like crazy (typically I will spin it around like I'm going to tie it, which extracts more liquid, then I also put it onto a canning rack above my kettle and apply pressure with the kettle lid).  I honestly can't perceive tannins.  I've recently heard that they are more of a result of low mash pH than applying pressure to the husk of the grain to extract liquid.  Makes sense I guess. 

Anyway, looking like I have a little more Kolsch than I planned for with a touch higher gravity.  One of those good problems I guess!

Cheers!

Tannins can result from a high mash pH, not low.

Denny, You are on it this morning... I am still not caffeinated enough to catch these things...

Only one cup so far, but it was a big one!