Grain volume in mash

[Proffs]

So I'm trying to figure out exactly how much volume grain takes up in the mash tun. I've recently got the 38L crab cooker & 104000 BTU burner from rays outdoors.

I did some googling and found a rough average of 0.32 quarts of volume per pound of grain. I worked that out to be around 660ml per kilogram grain. Does this sound right?

 

[QldKev]

It's the other way around, about 600g per L volume.

 

[QldKev]

When I started out brewing I used a 40L pot. I virtually ignored the grain bill for most beers. For a 66c mash, I used 29L of water @ 69c, and then sparged with 3 to 4L of water.

 

[Proffs]

Thanks QLDKev. So that's quite a bit of space then. I've been doing BIAB partial mashes and want to try use the same method with my new gear. I was hoping to try a full volume mash but that doesn't look like it would really work. I'll still have to sparge due to space.

So from what you said, that means you were limited to around 6 kilos of grain when adding 29L of strike water?

 

[Khellendros13]

If I worked it out right, 7kg of grain would displace 4.2L of volume. So if you mash with 3L:1kg, 7kg of grain will take up 25-26L of volume.

Is the absorption of water a factor?

EDIT: Wait, is it 11.66L for 7kg of grain? So 21L of water, 7kg of grain, and the volume would be up to 33L?

 

[Proffs]

If I worked it out right, 7kg of grain would displace 4.2L of volume. So if you mash with 3L:1kg, 7kg of grain will take up 25-26L of volume.

Is the absorption of water a factor?

EDIT: Wait, is it 11.66L for 7kg of grain? So 21L of water, 7kg of grain, and the volume would be up to 33L?

Yea, I'm reading it as 7kg displacing 11.66L.

 

[Rodolphe01]

The displacement thing isn't entirely correct, remember that the water you put in the mash will occupy the air spaces around the grain. i.e. your grain might occupy 11.66L, but you could potentially pour in litres of water and all it will do is fit around the grain, without actually changing the total volume occupied in the tun.

 

[QldKev]

Nothing that technical, forget displacement etc. It was just an easy volume in the pot without filling the pot all the way to the top once the grain was in. Most my 3L sparges were just using cold water poured over the bag once lifted. 6kg/7kg of grain would be a big beer. I'm currently drinking my Aussie Gold that has 14.7kg in a 112L batch. But I guess if you wanted a high alc beer, all is good.

What I meant earlier when I said "I virtually ignored the grain bill for most beers" is
I always started with the same water volume, ie 29L.
Then I added the grain as per recipe, and mashed.
Lift the bag and drained what I could from it.
Then all I did was sparge until I hit that 29L level again

More grain holds more water, but who cares, that just means a bit more sparge water to get back to my magical 29L mark.


edit: sorry had some 32L levels in there. This was when I did a slightly bigger batch size.

double edit:
My 29L level comes from 29L with a 15% boil off = 24.65 post boil.
Then that allows 1.65L lost to the kettle trub, so 23L wort volume.

 

[Arghonaut]

I have the 38l pot and do exactly as Kev. Fill up with 30L, which handily is the bottom of the handle rivets. Mash away, raise the bag after mashout and let drain, just before boil top up with ~5 litres of water.

My volumes are slightly higher as I lose more to trub and evaporation.

 

[QldKev]

The displacement thing isn't entirely correct, remember that the water you put in the mash will occupy the air spaces around the grain. i.e. your grain might occupy 11.66L, but you could potentially pour in litres of water and all it will do is fit around the grain, without actually changing the total volume occupied in the tun.

There's 3 displacement values of interest.
Uncrushed grain, crushed grain, and wet crushed grain.

Technically even different grains displace different vols per weight. eg, crystal is heavier per vol than say bb ale. The 600g/L is just a generalised value to give you an idea.

 

[Proffs]

I'm with you now QldKev & arghonaut. I think sometimes when your learning you make things more difficult than they have to be. I keep trying to please this bloody beersmith but I think I'll get a few brews down and come back to it when I know what to expect from my gear. Cheers

 

[sierensp]

1 kg malt ~ 0.7 L in the mash