grain absoption ratio

[Kaiser]

I'm working on a Wiki article about Batch Sparging analysis (basically what Ken Schwarz did, but trying to explain the subject with graphs rather than dry fomulas). For that I need realistic values for grain absoption ratios. On the web I find anything from 0.08 gal/lb to 0.2 gal/lb. My own notes suggest 0.15 gal/lb.

What do you guys use for grain aborption in case you care about this parameter?

Kai

 

[Boston]

I use 0.1 gallon/pound but I don't get too worked up about it

 

[Beerrific]

there is a table in designing great beers
table 8.1 on p. 64

EDIT: here it is, enjoy
lbs of grain gallon lost
3 0.675
4 0.875
5 1.000
6 1.300
7 1.500
8 1.750
9 2.000
10 2.125
11 2.375
12 2.500
13 2.750
14 3.000
15 3.250
16 3.500
17 3.675
18 4.000
19 4.125
20 4.330
21 4.500
22 4.750
23 5.000
24 5.250
25 5.500

So this comes out to 20% grain and 80% water of the total weight of the wet grains.

 

[Kaiser]

there is a table in designing great beers
table 8.1 on p. 64

...
10 2.125
...

Thanks for the effort. This looks like 0.21 gal/lb, which is on the high end of the spectrum so far.

Kai

 

[Beerrific]

Thanks for the effort. This looks like 0.21 gal/lb, which is on the high end of the spectrum so far.

Kai

Yeah I read it again and he later says it is 0.2gallon/lb.

I have used 0.1 and that is low for me, I am somewhere between 0.1 and 0.2.

 

[the_bird]

I started out using 0.1 gallons/lb, but always seemed to end up short in my volumes. Since I went to 0.2 gallons/lb, I've been pretty much spot-on. Negligible dead space in the cooler, as well, so I'm pretty confident that the 0.2 number has been good.

 

[bradsul]

I usually figure on around 40% absorption loss. I don't really speak gallons/quarts/pounds so I'm not sure how that measures up with your numbers.

Edit: I just checked my promash settings to confirm and I have it set at 1L/KG.

 

[Jo3sh]

Last batch, I had mine set at 0.15, and I came up a bit short. I'm going to try 0.18 or 0.20 next time.

 

[Got Trub?]

I have 2 different mash tuns, one I use 0.12, the other 0.14. This is both grain absorption and dead space in the tun which is probably why everyones numbers vary alot.

GT

 

[Blender]

I use .15 and it has been working well for me. How much do you think the crush affects this because I crunch mine pretty good.

 

[Kaiser]

I use .15 and it has been working well for me. How much do you think the crush affects this because I crunch mine pretty good.

I do think the crush should have a significant impact as it determines how dense the mash will be.

And from what I have seen so far, the grain absorption has a significant impact on the max achievable efficiency for batch sparging. An average 10 lb grist batch goes from 81 % efficiency to 91% efficiency for a 2 run-off sparge when you change the absorption ratio from 0.2 to 0.1 gal/lb. But I'm getting ahead of myself here.

Kai