Beersmith, BIAB and Cooling Shrinkage

[geoffm33]

I was reading an old post that didn't seem to come to a resolution. It was in the All-Grain forum and not software, so I am creating this new thread in Software to hopefully get some answers.

Essentially, for BIAB brewers using Beersmith, do you zero out the "Cooling Shrinkage" value in your equipment profile since the full volume into the kettle is measured cold?


Here is a quote from the OP of that thread:

I have a question regarding the cooling shrinkage calculation when dealing with a BIAB type setup.

I do a no-sparge style BIAB and fill my kettle with the full volume right out of the gate. This is cold water, which I then heat to strike temperature, add my bag and dough in.

It seems to reason that I should set the cooling percentage to 0% in Beersmith as I'm starting with already-cold water that will expand when heated, and then contract again once cooled.

My Equipment and Mash profiles combine to give me this for a typical recipe:

Volume Tab

* MASH *
Tot Mash Water: 8.08 gal
Grain Absorption: .74 gal
Water Avail from Mash: 7.34 gal

* Boil and Fermentation *
Kettle Top Up: 0 gal
Est Pre-Boil Vol: 7.34 gal
Boil Off: 1 gal
Post Boil Vol: 6.34 gal
Cooling Shrinkage: .25 gal
Trub Loss: .6 gal

* Fermentation/Bottling *
Batch Size: 5.5 gal

Since I put the initial 8.08 gallons into the my Boil Kettle cold (BIAB, Full Volume) I will end up with an extra .25 gallons in the kettle assuming I hit my trub loss, boil off and grain absorption numbers.

 

[raysmithtx]

I'm not Brad Smith so I could be wrong here...
If you look under the Vols tab, the cooling percentage is shown in the Boil and Fermentation section and I believe it relates to the Post Boil Volume. So if you measure the volume at the end of the boil boil time (while the water is still boiling or still very close to boiling) to get the recommended post boil volume number then the cool shinkage comes into play there.

The numbers work out perfect (at least for me) if I take the Post Boil Volume and multiply it by .96 (4% cool shrink), then subtract the Trub Loss to get the Amount into the Fermentor.

 

[Snicklefritz]

I'm not Brad Smith so I could be wrong here...
If you look under the Vols tab, the cooling percentage is shown in the Boil and Fermentation section and I believe it relates to the Post Boil Volume. So if you measure the volume at the end of the boil boil time (while the water is still boiling or still very close to boiling) to get the recommended post boil volume number then the cool shinkage comes into play there.

The numbers work out perfect (at least for me) if I take the Post Boil Volume and multiply it by .96 (4% cool shrink), then subtract the Trub Loss to get the Amount into the Fermentor.

+1 to this. That setting, as far as I understand it, is how much wort is lost due to evaporation between flameout and pitching temps

 

[tootal]

Cool Shrinkage? Sorry, I really don't want to talk about it...

 

[geoffm33]

It's certainly a little confusing:

From the values in the OP:

(Tot Mash Water: 8.08 gal measured at 45°F) - (Grain Absorption: .74 gal) = (Water Avail from Mash: 7.34 gal)

(Est Pre-Boil Vol: 7.34 gal) - (Boil Off: 1 gal) = (Post Boil Vol: 6.34 gal)

(Post Boil Vol: 6.34 gal) - (Cooling Shrinkage: .25 gal) - (Trub Loss: .6 gal) = (Batch Size: 5.49 gal)

So my original kettle volume of 8.08 is measure at 45°. (If I were using an HLT and MLT, I'd be measuring the total mash water at 150° F +)