Grain absorption question

[BBKing]

Next weekend I will be doing my first all grain batch. I'm brewing MWS's Irish Red ale with a grain bill of 10lbs. 4 oz.

According to their instructions they say 1.25 quarts per pound of grain for the mash, then a half gallon per pound for the sparge. After quickly calculatiing that comes out to 8.125 gallons of water.

Does that seem waaay high to anyone else? What is the general rule of thumb on grain absorption? My main concern is that I'll be boiling for an hour and a half before I am even able to starting throwing hops in.

Any help is appreciated. I did a quick search, but time is limited for me tonight.

FWIW, I will also be batch sparging if that makes a difference.

Thanks

 

[Misplaced_Canuck]

0.1 lb/gallon is the generally accepted absorption rate. So with 10+lbs of grain, you'll lose apx 1 gallon of liquid.

so 1.25qt per lb * 10.25 / 4qt/gal = 3.2 gallons
10.25 * .5 gal/lb = 5.125g
total: 8.325g

minus absorption 0.1g/lb * 10.25lb = 1.025g

8.325 - 1.025 = 7.3 gallons. Boil off rate of about 1.5g/hour = 5.8gal.

It's not too far off, but it really depends on your evaporation rate.

M_C

 

[Pappers_]

Hi BB. If you haven't already seen these, they are a great resource for info on all-grain mashing and batch sparging. The first is from Denny, who I admire greatly for his keep-it-simple approach http://hbd.org/cascade/dennybrew/ Next is from Bobby who also has a knack for explaining the mashing and batch sparge process in easily digestable ways http://www.suebob.com/brew/Bobby_Mallgrainprimer.pdf

Over 8 gallons of water does not seem way high to me. With my setup, doing 5.5 gallon batches, I want to start with about 7 gallons of wort pre-boil (I lose about 1.5 gallons over the course of an hour long boil.) So I batch sparge until I have 7 gallons of wort.

Good luck with your Irish Red! Cheers,

Jim

 

[Sean]

0.1 lb/gallon is the generally accepted absorption rate. So with 10+lbs of grain, you'll lose apx 1 gallon of liquid.

so 1.25qt per lb * 10.25 / 4qt/gal = 3.2 gallons
10.25 * .5 gal/lb = 5.125g
total: 8.325g

minus absorption 0.1g/lb * 10.25lb = 1.025g

8.325 - 1.025 = 7.3 gallons. Boil off rate of about 1.5g/hour = 5.8gal.

It's not too far off, but it really depends on your evaporation rate.

M_C

Nice post.

Sometimes I sacrifice efficiency and sparge a little light. You can also mash with a bit less. 1 to 1.25 is good.

Today I did a Celebration clone with 13# of grain with 75% efficiency. (Or thereabouts). Mashed with 3.5 gallons. Sparged with a bit over 5 gallons. Then boiled down to about 5.5. I boiled for 70 min. O.G. was 1.067.

The point is that, IMO, you don't have to stick right on the volumes. just keep it in the range. If you have too much to start, put some in a second pot and put it on the stove to boil down so you can really crank up the heat on the big burner. If you don't have enough add water. The objective is to hit your intended original gravity, with your intended bitterness.

This will take a few sessions. Luck.

 

[aggieactuary]

I just did my second AG batch yesterday and measured my volumes.

I had 8 gallons total water (3.5 gal mash, 4.5 gal sparge), but I only got 5.75 gal pre-boil. So, I must lose more than average there.

But then I boiled for 60 minutes and ended with 5.25 gal. I use a heatstick and don't get a raging boil, so I guess I lose less than average there.

So, start with the averages, but measure volumes and see how your system works.

 

[WyomingBrewer]

http://www.brew365.com/mash_sparge_water_calculator.php

I use the numbers from here and just leave their % in. Seems to come out very close.

 

[RedHouse]

I brewed a dry stout awhile back that had about the same amount of grain(10.5 lbs) and beersmith calculated 8.5 gallons for mashing and sparging. I like a bit over 7 gallons pre-boil to end up with 5.5 gallons post boil.

Good luck with the brew!