how much volume does a lb of grain typically have?

[mongoose33]

I skimmed this thread, and the first thought that came to mind is what kind of grain? I've got some rye that has tiny kernels compared to typical barley malt; I haven't weight out a pound of each to see their volumes, but I'll bet a pound of the Rye has less overall volume than a pound of the Barley.

If we're talking about crushed grain, then it may be different; it may also depend on the coarsness of the crush.

BTW, @andy6026 , I have a 48-quart igloo cooler I use for mashing. A typical grain bill has 12-13# of grain, and I'm underletting with about 8 to 8.25 gallons of water. Analogous to a BIAB with no sparge. That cooler is pretty full, but if I went to 20# of grain, I am not sure it would all fit, grain and water. If I were doing a mash water volume of 1.5 quarts per pound, that would be 30 quarts, 7.5 gallons. Might be close, but still tight.

 

[pricelessbrewing]

Aside from different grains absorbing different amounts, and having different kernel densities, there's thermal expansion which can realistically account for an additional 2-2.5% of your water volume at mash temps.

At this point we're still missing ~4 qts in your example @andy6026. I'd have to ask how you're measuring your water volumes, are you using a pitcher, weight, etc?

 

[bleme]

Measure 48 quarts of water into that cooler and see for yourself. If it doesn't fit, you know that either it isn't a 48 qt cooler or your quart measurement is off.

 

[andy6026]

As much as that would certainly answer my question, bleme, going through those motions is a little more effort than I want to expend to find out. I guess what I'm getting at is that regardless whether or not Coleman is lying, my 48 qt cooler just isn't cutting it for 10 gallon batches (so mongoose33 - we are agreed!), despite the measurements above saying that it should work. So I bought a 70 qt cooler today which I'm guesting should be perfect - although the point of threads like this is to answer such questions with more precision than that.

Bottom line so far peeps (at least for me): if you want to mash and sparge a 10 gallon batch in a 48 qt Coleman cooler without sparging twice, then you likely won't be able to do it and your floor's going to get wet... unless you like really low alcohol beer!

I've bought a 70 gallon cooler this afternoon and have converted it... will report back after my next brew day.

Ps: to answer pricelessbrewing's questions, I've long noticed that the factory volume markings on fermenter buckets are often waaaay off the mark (perhaps this is why you asked me how I measure), so I used a large kitchen measuring pitcher to re-mark a fermenter bucket which I've since used to calculate my water volumes on brew day.

Thanks everybody!

 

[pricelessbrewing]

Ps: to answer pricelessbrewing's questions, I've long noticed that the factory volume markings on fermenter buckets are often waaaay off the mark (perhaps this is why you asked me how I measure), so I used a large kitchen measuring pitcher to re-mark a fermenter bucket which I've since used to calculate my water volumes on brew day.

Thanks everybody!

See this may not be much better. In general the measurmental uncertainty is going to be half the smallest unit that's marked. So lets say you're filling your pitcher 9 times for the example of 37 qts for mash water, and it's only as accurate as a cup, this gives your re-marked fermenter bucket an uncertainty of about 37 qts +- 2.25. This is more than reasonable.

If however you use weight as the standard, you can be much more accurate.

Not saying it's the sole reason, but it's likely a contributing source of error.

 

[mongoose33]

I was thinking about this when I brewed today (yeah, I was able to take off a bit early). Below is a pic showing my 48-quart cube cooler where I have about 8+ gallons of water plus 12# 13 ounces of grain. It seems to me that I would have been able to add maybe 2 more gallons of water to this before I was pushing the very limits.

 

[davidabcd]

I was just getting ready to post the OP's question, so please permit me to summarize the discussion here for the benefit of my feeble mind;

Given: I need to check that my kettle is big enough to soak X pounds of dry grains.

Therefore;

1. I put 1 gallon of clear water in the pot

2. I add 1 pound of dry grains

3. The grains ultimately soak up .13 gallons, leaving 0.87 gallons of theoretical" runnings, ignoring things such as equipment loss, etc.

4. Initially the dry grains float on the surface. As they soak up water, they sink into the water volume

5. Once fully saturated, the combination of grains and water occupy a total of 1 gallon plus .32 quarts, or .08 gallons. Therefore, to soak 1 pound of grains a pot of 1.08 gallons is required.

Therefore, If i have a grain bill of 12 pounds and want to end up with 7 gallons of runnings, I need a pot that will hold:

7 gallons + 1.56 gallons absorption + .96 gallons displacement=9.52 gallons (assuming I can boil "to the brim, which is silly, but this is beer math, what the hell)

AND I need to ultimately soak 7 gallons water plus 1.56 gallons absorption=8.56 gallons combined strike and sparge water.

I assume that mashing temps do not evaporate a volume of water sufficient to be significant for our purposes. (this is beer math in the basement, not in the lab)

sorry for off topic. You get a plus one for your name.

 

[william_shakes_beer]

The numbers given here are estimates. In addition to absorption there is also displacement ( the grains take up space). To add a personal data point, I have always used these figures in my brew-in-a-bag setup to verify my container is sufficient. Of course, I need not be particularly precise because my mash tun/kettle is 15 gallons and I don't do batches over 10 gallons. There are going to be variances based on deadspace in the bottom of the tun, moisture content of the grains, etc. If the batches you usually do are in danger of overflowing the tun, you need a bigger tun. If your sensibilities require more precision, I'd suggest you get a graduated water measure, a red oak dowel and a sharpie. Pour 2 quarts of water into the empty tun with the sparge braid in place. Place the dowel in the center and draw a line. Repeat until adding another container of water overflows the tun. That's your real capacity. Now place 4 gallons of mash temp water from your graduated stick into the tun. Add 4 pounds of milled grains and let it sit 30 minutes or so. Poke in the stick and see what the apparent volume is. Thats your volume factor. Repeat for as many grains as required to satisfy your sensibilities.

 

[andy6026]

The numbers given here are estimates. In addition to absorption there is also displacement ( the grains take up space). To add a personal data point, I have always used these figures in my brew-in-a-bag setup to verify my container is sufficient. Of course, I need not be particularly precise because my mash tun/kettle is 15 gallons and I don't do batches over 10 gallons. There are going to be variances based on deadspace in the bottom of the tun, moisture content of the grains, etc. If the batches you usually do are in danger of overflowing the tun, you need a bigger tun. If your sensibilities require more precision, I'd suggest you get a graduated water measure, a red oak dowel and a sharpie. Pour 2 quarts of water into the empty tun with the sparge braid in place. Place the dowel in the center and draw a line. Repeat until adding another container of water overflows the tun. That's your real capacity. Now place 4 gallons of mash temp water from your graduated stick into the tun. Add 4 pounds of milled grains and let it sit 30 minutes or so. Poke in the stick and see what the apparent volume is. Thats your volume factor. Repeat for as many grains as required to satisfy your sensibilities.

This would be a very sensible way to determine the volumes required. Unfortunately it is more involved than I was hoping to do and I have already upgraded to a 70 qt cooler. I haven't used it yet, but I'm excited to test it out soon. What I was hoping for were some quick and easy calculations based on a cooler's manufacturer claims as to the volume of the tun and the general guides presented in this thread regarding grain volume and absorbency. From good estimates we should be able to determine with fairly decent precision how many pounds of grain can be mashed and sparged (and by that I mean single-sparged) in a 48 qt cooler, 70 qt cooler, 100 qt cooler, etc. I'm quite surprised that there isn't a handy chart like this available. There are 'can i mash it' charts that do exactly this, but only seem to take into account the mash stage. A proper chart would likely be very helpful for folks that are shopping for a new cooler and who are obviously not yet able to do the test above that you've suggested. Well, at least that was the predicament I was in...