Beersmith BIAB w/ batch sparge grain absorption

[Javaslinger]

Curious what people set their grain absorption to when doing BIAB with a batch sparge?

BIAB Default 0.586 fl oz/oz
Mash Tun Default 0.960 fl oz/oz

So if using a mash profile such as Single Infusion, Batch Sparge while doing BIAB, should I set it to 0.586 or somewhere in the middle. I know I can back calculate from a brew day, but I'm trying to get a ball park to begin with from everyone else.

Thanks!

 

[Biscuits]

This depends on whether or not you're squeezing or if you're just using the bag as a filter in your mashtun. If the latter, set it to the Mash Tun default as it is not any different than a traditional method of using a false bottom or bazooka tube. If you are mashing, sparging, and then squeezing, set it to the BIAB default as you will be recovering more trapped liquid from the grain with the squeeze.

 

[kevin58]

Do a full volume mash. Squeeze that bag until you get every drop out. What's left is your final volume.

 

[McKnuckle]

Normally we use gal/lb for absorption, at least I do... So let's convert:

0.96 fl oz/oz = 0.12 gal/lb.
0.586 fl oz/oz = 0.07 gal/lb.

I get about 0.1 gal/lb for BIAB when I do not do an extended gravity drain or squeeze, and 0.08 gal/lb when I do. Sparging is irrelevant, because the grains retain the same amount of liquid regardless of how many times you run water through them.

 

[frozyn]

I usually get about 0.05 gal/lb absorption, as measured across multiple batches, which equates to about .42 fl oz/oz.

I usually use Priceless as my water volume calculator, never thought to go in and update Beersmith to see if I get better predictions from them.

 

[doug293cz]

I usually get about 0.05 gal/lb absorption, as measured across multiple batches, which equates to about .42 fl oz/oz.

I usually use Priceless as my water volume calculator, never thought to go in and update Beersmith to see if I get better predictions from them.

That's a pretty low absorption rate! Do you have any special bag squeezing techniques you use?

Brew on

 

[kjf45]

That's a pretty low absorption rate! Do you have any special bag squeezing techniques you use?

Brew on

My last brew with a 15.5Lb grain bill I calculated the same and came up with 80% efficiency. I set my bag in a collander that sits perfectly into a 5 gallon bucket and squeeze/push till nothing comes out. I do it in a few steps.

Squeeze to get a good bit of wort out dump into kettle. Rotate bag squeeze again, rotate squeeze and repeat till im satisfied. By the time im done the worts coming up to a boil, takes maybe 10-15 minutes depending on how hard im pushing.

 

[frozyn]

That's a pretty low absorption rate! Do you have any special bag squeezing techniques you use?

Brew on

My last brew with a 15.5Lb grain bill I calculated the same and came up with 80% efficiency. I set my bag in a collander that sits perfectly into a 5 gallon bucket and squeeze/push till nothing comes out. I do it in a few steps.

Squeeze to get a good bit of wort out dump into kettle. Rotate bag squeeze again, rotate squeeze and repeat till im satisfied. By the time im done the worts coming up to a boil, takes maybe 10-15 minutes depending on how hard im pushing.

That sums it up for me as well. I double crush my grains at my LHBS, so I imagine I could (1) up my efficiency, or (2) decrease my intense squeezing if I had my own mill set to .020 or some such, but it works for me for now.

Edit: I forgot to say, I do use a small pot lid to start the process off, but always end up using my hands (with gloves on, of course!) to really get my hands in there and get the wort out.

 

[doug293cz]

That sums it up for me as well. I double crush my grains at my LHBS, so I imagine I could (1) up my efficiency, or (2) decrease my intense squeezing if I had my own mill set to .020 or some such, but it works for me for now.

Edit: I forgot to say, I do use a small pot lid to start the process off, but always end up using my hands (with gloves on, of course!) to really get my hands in there and get the wort out.

Since mash efficiency = conversion efficiency * lauter efficiency, you can improve your mash efficiency by improving either, or both, of the contributing efficiencies.

Crush primarily affects conversion efficiency. You can actually quantify your conversion efficiency using the method here. If you are not getting at least 90% conversion efficiency, you should look into getting a finer crush, and/or mashing for longer times.

Squeezing increases lauter efficiency since it reduces the grain absorption rate. You can see how grain absorption rate affects lauter efficiency in the chart below.

Of course if you are happy with your current efficiency, and it is consistent, then you don't have to do anything. Consistency is more important than the actual efficiency.



Brew on