• Welcome to the new forum! We upgraded our forum software with a host of new boards, capabilities and features. It is also more secure.
    Jump in and join the conversation! You can learn more about the upgrade and new features here.

Measuring grain absorption

pedrovic

Apprentice
Joined
Sep 12, 2020
Messages
14
Reaction score
0
Hi, I hope everyone's okay.
I realized that the default values for the grain absorption of BS don't correspond to the values measured in my post-mash volume. As I don't want to lose my next batch, I thought I'd measure the absorption in small scale, with 1oz of malt pilsner in a cup of water and calculate the volume difference after 1 hour. Is this method correct?
Thank you
 

Oginme

Grandmaster Brewer
Joined
Mar 16, 2013
Messages
3,156
Reaction score
1
Location
New Hampshire, US
Since you are doing BIAB (I am assuming since you posted this in the BIAB topics), the measurement of grain absorption is pretty easy.

Add your water into the kettle and measure your volume when at strike temperature.  Do your mash and remove the grains.  Add back any wort you squeeze out or allow to drip out, then take another volume measurement.

Difference in measurements if your water absorbed into the grain. Take this value and divide it by the weight of the grain and you have your grain absorption rate to plug back into BeerSmith.

 

pedrovic

Apprentice
Joined
Sep 12, 2020
Messages
14
Reaction score
0
The units used in this calc is gallons for water and pounds for grains?
Thanks for the help. Yes, I'm using BIAB.
 

pedrovic

Apprentice
Joined
Sep 12, 2020
Messages
14
Reaction score
0
I used 2.2 gal in my initial volume of water (I brew small batches), with 3.3 lb of malt. After I removed the grain bag, the new volume was 2.0 gal in the kettle. I did this calc and the result was 0.0559. It would be correct?
 

Oginme

Grandmaster Brewer
Joined
Mar 16, 2013
Messages
3,156
Reaction score
1
Location
New Hampshire, US
BeerSmith absorption uses fixed units of fluid ounces per ounce of grain.  So, in your case:

Volume loss = 2.2 gal - 2.0 gal = 0.2 gal * 128 flu oz/gal = 25.6 fluid ounces

Grain weight = 3.3 lbs * 16 oz/lb = 52.8 ounces

Absorption = 25.6 fluid ounces / 52.8 ounces = 0.4848 fl oz/oz of grain

Hope this helps with the conversion broken down.
 
Top