Grain Displacement Question

[cubalz]

I am getting ready to brew a 1.049 OG 5 gallon beer recipe but want to use my smaller 10 gallon kettle (it was a wife present and I have not used it in a while) instead of the 15 gallon one and I want to make sure it can handle the recipe. The total grain bill is 11 lb 3 oz and the software I use calls for 7.4 gallons of strike water for no sparge. What that translates in my mind is that I have a little less than 2.5 gallons worth of displacement before it overflows when I add all of the grain to the BIAB. I have been on a number of internet sites where you can plug in numbers (like Green Bay Rackers etc) and keep getting different numbers. Can anyone definitively confirm how much the above grain bill will displace. The kettle is 13.8 inches in diameter.

Thanks!
John

 

[MaxStout]

7.4 gallons is 29.6 qts, and with 11.2 lbs grain, that works out to about 2.64 qt/lb mash thickness. Plugging that into this calculator (the Can I Mash It? calc), it shows 8.32 gallons total volume. It should work with your 10 gal BK.

 

[bleme]

Max is right. I am curious which sites said that you would need more than 10 gallons though.

 

[MaxStout]

A good rule of thumb is that 12 lbs. crushed grain will displace about 1 gallon volume in the strike water. Initially it might displace a little more, until the grain is well mixed into the mash and it becomes saturated. But that shouldn't be much of an issue if you dough in gradually and don't dump the entire grain bill in at once. My process is to pour in about 1/3, stir, pour another 1/3, etc. This minimizes dough balls, too.

 

[cubalz]

Thanks guys!!!! That is what I had suspected but wanted to confirm. My wife noticed that I had not been using the small kettle since I built the beer room and started using the 15 gal kettle with the Kal clone panel. I thought it would make her happy if we brewed together on the next batch and heating it on my IC 3500 induction range. Damn, I love this forum!

 

[MaxStout]

Max is right. I am curious which sites said that you would need more than 10 gallons though.

I can't recall where, but I remember one source stating something along the lines of .75 qt/lb displacement, which would be about 1 gallon displacement for 5.33 lbs grain, more than double what I calculate. My experience has been close to the 12 lb/gal figure, which is what Green Bay Rackers shows.

 

[cubalz]

The site where I got conflicting numbers was Priceless Brew Calculator which did show .75 qt/lb by default. I am sure it was my doing when inputting data and not changing it

 

[MaxStout]

The site where I got conflicting numbers was Priceless Brewing which did show .75 qt/lb by default. I am sure it was my doing when inputting data and not changing it

I find that volume quite high. I can't imagine a situation with .75qt/lb displacement. Maybe if you were using a lot of fluffy grains, like flaked barley or oats. Even then, hard to imagine more than doubling displacement.

 

[PADave]

My last brew had 15 lbs of grain, with 7.7 gal of water in a 10 gallon kettle 1.075 og. Had plenty of room, could go a few more pounds.

 

[cubalz]

Thanks PADave.

 

[soccerdad]

The site where I got conflicting numbers was Priceless Brew Calculator which did show .75 qt/lb by default. I am sure it was my doing when inputting data and not changing it

Just curious, was that per Q or per G ? When I use the Priceless calc it shows me a difference in kettle height with grain added and water volume with grain added. The default is inches for kettle height and gallons for water volume.

 

[jeeppilot]

My last brew had 15 lbs of grain, with 7.7 gal of water in a 10 gallon kettle 1.075 og. Had plenty of room, could go a few more pounds.

I’m getting ready to buy a bag for getting into BIAB. I mostly plan on 2.5 gal batches but would to do big 5 gal batches if so inclined.

I have a 10 gal kettle I plan to use, but after looking at my last 5 gal batch (1.081 OG and 15.9 lbs grain) my total water needed was 9.67 gal, which obviously wouldn’t work. Granted it was a 90 minute boil, but that only added an additional .66 gal or so. I’m curious how you managed to only use 7.7 gal of water when nearly 2 gal would be absorbed by the grain? Do you squeeze out to reduce that number and therefore the total water needed? For reference, my water needed shows:

9.67 gal total - 1.99 gal grain absorption - 1.88 gal boil off - .26 gal misc losses -.06 gal hops absorption = 5.5 gal into the fermenter.

 

[bleme]

I have a 10 gal kettle I plan to use, but after looking at my last 5 gal batch (1.081 OG and 15.9 lbs grain) my total water needed was 9.67 gal, which obviously wouldn’t work. Granted it was a 90 minute boil, but that only added an additional .66 gal or so. I’m curious how you managed to only use 7.7 gal of water when nearly 2 gal would be absorbed by the grain? Do you squeeze out to reduce that number and therefore the total water needed? For reference, my water needed shows:

9.67 gal total - 1.99 gal grain absorption - 1.88 gal boil off - .26 gal misc losses -.06 gal hops absorption = 5.5 gal into the fermenter.

For BIAB, a better calculator would be http://www.biabcalculator.com/ as it has most of the right defaults.

I don't know why anyone would not squeeze BIAB, but I'm on the other fringe and squeeze twice. If I were doing that, I'd set aside 2 gallons. Mash in the remaining water, squeeze, pour the 2 gallons over/through, and squeeze again.

 

[PADave]

I’m getting ready to buy a bag for getting into BIAB. I mostly plan on 2.5 gal batches but would to do big 5 gal batches if so inclined.

I have a 10 gal kettle I plan to use, but after looking at my last 5 gal batch (1.081 OG and 15.9 lbs grain) my total water needed was 9.67 gal, which obviously wouldn’t work. Granted it was a 90 minute boil, but that only added an additional .66 gal or so. I’m curious how you managed to only use 7.7 gal of water when nearly 2 gal would be absorbed by the grain? Do you squeeze out to reduce that number and therefore the total water needed? For reference, my water needed shows:

9.67 gal total - 1.99 gal grain absorption - 1.88 gal boil off - .26 gal misc losses -.06 gal hops absorption = 5.5 gal into the fermenter.

Don't know where you are getting that 1.99 gal number, my grain absorption for that brew was .75 gal. I squeeze the bag like it owes me money.

 

[jeeppilot]

Don't know where you are getting that 1.99 gal number, my grain absorption for that brew was .75 gal. I squeeze the bag like it owes me money.

The grain absorption number is from Brewer’s Friend, default setting of .5 qt/lb. So, 16 lbs of grain would be 8 qts or 2 gal. Does that seem way off?

 

[PADave]

The grain absorption number is from Brewer’s Friend, default setting of .5 qt/lb. So, 16 lbs of grain would be 8 qts or 2 gal. Does that seem way off?

For me it sure would be. I also use Brewer's Friend, just checked my numbers, and I have grain absorption as .2 qt/lb.

 

[bleme]

The grain absorption number is from Brewer’s Friend, default setting of .5 qt/lb. So, 16 lbs of grain would be 8 qts or 2 gal. Does that seem way off?

Brew365 defaults to .13 gallons per pound, no squeezing, which is .5 qt/lb but BIABcalculator defaults to .045 (.18 qt/lb) for a squeezed bag.

 

[MaxStout]

The water absorption rates are going to be all over the road, based on crush, how long you let the bag drain, squeezing, etc. I hoist out the bag (Wilser's ratchet pulley, FTW!), and let it drip over the kettle for the time it takes to bring to a boil, about 20 minutes or so. I give it a gentle squeeze, too, but I don't put a lot of effort into that. In all, I lose about .33 qt/lb, which is about 1 gal for 12 pounds. PADave squeezes more and loses less wort.

The calculators are a blunt instrument for predicting this, and your own empirical measurements will give you a more real world answer.

 

[jeeppilot]

Wow I wonder if Brewers Friend assumes for all grain you drain your MT and then close the valve. No real draining or certainly squeezing of the grain inside your MT. I’ve done that only to realize 30 minutes later there’s a bunch of wort sitting in my cooler!

Thanks for the info everyone!

 

[pricelessbrewing]

The site where I got conflicting numbers was Priceless Brew Calculator which did show .75 qt/lb by default. I am sure it was my doing when inputting data and not changing it

The Priceless biab calc should have a default displacement of 0.08 gal/lb, and 0.08 gal/lb absorption rate. The only variable that even uses qt/lb as a unit is mash thickness, which the default should either be 0 (meaning full volume mash), or 1.75 qt/lb.