volume calculation when mashing

[hagar681]

Can anyone give me a general estimate or explanation on how much the addition of grains increases volume. If I was planning on creating a 300 gallon mash and was planning on a ratio of about three pounds of grain per gallon of water would 200 gallons of water and 600 pounds of grain increase my volume to 300 gallons? I'm sure I could take one gallon of water and add three pounds of grain and calculate and multiply, but I was wondering if there was an actual rule of thumb or calculation out there.

[Lenny]

Not sure if explanation of my process is helpful since I mash, sparge, and lauter my wash (vs. fermenting on the grain) but...

I fill my 300g mashtun with 175-200g of water and then mix in 750# of grain malted barley. That ratio just about maxes out the capacity of my 300g mashtun.

[jeffw]

Will depend on the grain and I have never seen an absorption factor by grain type...if anyone has a chart please post it.

[hagar681]

Very helpful. I was just looking for a ballpark. I didn't want to heat up 200 gallons of water and then realize I only had room for 200 lbs of grain.

[jeffw]

You have 40 cubic feet of space in a 300 gallon mashtun. 200 gallons of water is is around 27 cubic feet, 600 pounds grain is around 13 so assuming no absorption you are still fine and there will be some absorption. Those calcs are very rough of course but you should be fine.

[stevea]

In the brewing industry a figure of 0.66 - 0.67 l/kg (~8 gallon / 100lb) has been in use for a long time (I can't find a source in my reference books). Of course this is for crushed malted barley,.

So the 750# example might displace ~60 gallons of volume once fully wetted and infused.