Another batch sparge question. Trouble with a big beer.

I have been using the BIAB method for a couple of years with good success but am moving to a cooler for mashing and batch sparging to improve my efficiency.
I have read a ton but cannot wrap my mind around the strike and sparge water volumes for a big beer.

We are using a 70qt converted Igloo Xtreme cooler.
8 Gallon batch, Russian Imperial Stout
33# of grain

At 1.25qts per pound that would be 41.25qts/10.3gals of strike water. With a 10% absorpsion rate, that would be 9.25gals from the first runnings. This only leaves about gallon to a gallon and a half for sparge water volume. I know I could sparge with a bit more water and increase my boil time and vigor to get a bit more boil off, but it seems so little water would yield almost nothing.

I have also read that Denny suggests trying to get about 1/2 the preboil water from the first runnings and 1/2 from the sparge/2nd runnings. At that rate I would less than .65qts of water per pound for my strike water.

I feel like I am likely missing something basic here. Any thoughts would be appreciated.
Lakedawgs

Mash thicker and increase your boil time. You could also increase your grain bill and do the RIS from your first runnings and a partigyle with the remaining sugar.

I thought about doing a partigyle but this 8 gallon batch is the first of 3 I am doing for my share of a bourbon barrel addition. Unless I hear different I think I am going to strike with about 8 gallons (just under 1qt per gallon), and sparge with about 3.5 gallons.

The 1.25 to 1.5 qt/lb is fine for a regular brew, but with really big, high gravity brews you want to lower it to 1 qt/lb. I've found when I forget to make this change my efficiency goes through the floor.

So you lower the qts/per pound formula a bit for big beers, that is really interesting. Is that simply so you can have a bit more sparge water or something else?

Firstly, the static 10% absorption might work with a specific mash thickness sometimes, but will be way off in many cases. I use 0.11 gallons/lb grain and it works very well. This would give you (0.11)*(33) = 3.63 gallons stuck in the grain. Sounds like a lot, but grain is a wort sponge.

Here is what I would do... just a suggestion.

I'd start with 9 gallons strike water to keep the numbers easy. That's 1.09 qt/lb.

You'd get approx. 5.25 gallons first runnings (9 - (0.11*33)) minus your dead space. Assuming a 2 hour boil (I do with a beer this big) you'll need 10.5 gallons pre-boil assuming ~1.25 gal/hr boiloff. Adjust for your system.

Sparge with 5.25 gallons RO water, since you'll get out exactly what you put into the sparge... the absorption is already accounted for.

I like that idea so far. I was thinking 10% absorption not .1 gal/pound of grain, thanks for the clarification, big difference.

lakedawgs said:

I like that idea so far. I was thinking 10% absorption not .1 gal/pound of grain, thanks for the clarification, big difference.

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You betcha. Like any formula, it's garbage in, garbage out... only as good as the inputs you give it. Once you get your system losses, absorptions, and volumes dialed in, you can estimate the whole process very well.

Really looking forward to start mashing and sparging in a cooler but my first 3 brews will be monster stouts so I want to have my #s and thoughts in the right direction from the start.

When you break the 1.100 OG barrier, it's just better to do a no sparge mash for the big beer and force yourself to partigyle for a second beer.

Are you saying a 'no sparge' batch will likely give the same #s as a small sparge?

Bobby_M said:

When you break the 1.100 OG barrier, it's just better to do a no sparge mash for the big beer and force yourself to partigyle for a second beer.

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Totally agreed.

lakedawgs said:

Are you saying a 'no sparge' batch will likely give the same #s as a small sparge?

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Well, let's do a bit of figurin and see.

8 Gallon batch, Russian Imperial Stout
33# of grain

At 1.25qts per pound that would be 41.25qts/10.3gals of strike water. With a 10% absorpsion rate, that would be 9.25gals from the first runnings. This only leaves about gallon to a gallon and a half for sparge water volume.

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33lbs x 36PPG = 1188 points but we'll round down to 1100 assuming a little typical conversion trouble.

Let's try an example with the stiffest mash you can get away with 1qt per pound is 33 quarts or 8.25 gallons. 1100/8.25 = 1.133 mash gravity. The grain is going to hold onto at least .1 gallons per pound so that's 3.3 gallons. First runnings would be around 5 gallons of 1.133 or a total of 665 points.

You sparge with another 5 gallons (I'm assuming you want 10g preboil). With 3.3 gallons of 1.133 still in the tun, you re dilute back to 8.3 gallons (@1.053). Again, you drain off only 5 gallons of that. The end result is (5*133)+(5*53)/10 = 10 gallons at 1.093.

No sparge: Assuming that 3.3g absorption, strike with 13.3 gallons. That dilution makes the mash gravity 1100/13.3 = 1.083.



Nope, it does appear that a sparge is better. I see that your original post you assume a 10% absorption rate but that's not really accurate. It's based on how much grain you have. Even with your original figure of 10.3g strike water, you'd get 7 gallons first runnings with a sparge of 3 gallons, not 1. One reason why my first example comes up with great numbers is that both runnings volumes are identical and therefore as efficient as you can get.

My knee jerk recommendation is based on a 6 gallon batch where it would be a LOT closer. I'm curious why the odd batch size of 8 gallons?

I realized the 10% absorption error via another poster later in thread. Makes a big difference for sure.

Reason for the odd size batch is that a buddy and I have bought a freshly dumped KY bourbon barrel. My share is 20 gallons. With the angels share and wanting to be on the heavy side I planned (3) - 8 gallon batches that will allow me to have 22+ gallons ready on fill day. Being the first batch in the barrel that is why we are going with such a big beer.

I am vascillating back and forth on sparge or no sparge. Right now I am thinking I am going to go with a sparge using the numbers you mention above and on the second brew going no sparge. Whichever yields higher will determine the way I do the third batch.

If fermenters are not your bottleneck, it may be a good idea to get your no sparge wort out of the tun, then sparge anyway and use that lower gravity wort as your strike "water" for the next mash. That's one way to not waste the sugar.

Bobby_M said:

If fermenters are not your bottleneck, it may be a good idea to get your no sparge wort out of the tun, then sparge anyway and use that lower gravity wort as your strike "water" for the next mash. That's one way to not waste the sugar.

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That is freakin' brilliant! We planned on a small beer from the 'no sparge' batch, but this is the way we will go. I still plan to run the #s on the 'sparge' vrs 'no sparge' batches, (taking the added sugary strike water in to account), so I can determine the best method for the third batch.

Thanks much for idea, the efficiency of the barrel beers are much more important that getting an 'freebie' small beer out of the deal. I will post my results next weekend. I look forward to seeing how things turn out. I have had strong opinions for sparge and no sparge from many people I consider very knowledgeable.
THANKS

lakedawgs said:

So you lower the qts/per pound formula a bit for big beers, that is really interesting. Is that simply so you can have a bit more sparge water or something else?

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From what I've read, it is because of the Ph of the mash and because mash thickness greatly effects the entire process. I just recently started doing additions calculated on the Bru'n Water spreadsheet and have seen my efficiency jump through the roof--I went from an average of 65% to 82% with just a bit of tweaking.

OK, had a good brewday but also, a lot of learning with the new setup.
On the first 'no sparge' batch I mashed in with 12 gals, filling the cooler to the max once grain was added. Only got 8 gals of first runnings so I added 3 gallons of sparge and only got 1.5 gallons out of it.

On the second, 'sparge' batch I mashed in with 9 gallons, got about 4.75 gals in first runnings, added 5 gallons sparge water but only got about 3.75 gals out of it, had to add a gallon of fresh water to the boil.

Overall today, I ended up averaging 1.095 and targeted 1.100, so not too bad on a virgin system, to me. I have a question though, I seemed to have a ton of absorption by the grain, and I thought, during sparge, since the grain was already saturated, I should have gotten a running volume almost matching the amount of liquid I sparged with. Is that not the case, because I did not seem to come close.

lakedawgs said:

OK, had a good brewday but also, a lot of learning with the new setup.
On the first 'no sparge' batch I mashed in with 12 gals, filling the cooler to the max once grain was added. Only got 8 gals of first runnings so I added 3 gallons of sparge and only got 1.5 gallons out of it.

On the second, 'sparge' batch I mashed in with 9 gallons, got about 4.75 gals in first runnings, added 5 gallons sparge water but only got about 3.75 gals out of it, had to add a gallon of fresh water to the boil.

Overall today, I ended up averaging 1.095 and targeted 1.100, so not too bad on a virgin system, to me. I have a question though, I seemed to have a ton of absorption by the grain, and I thought, during sparge, since the grain was already saturated, I should have gotten a running volume almost matching the amount of liquid I sparged with. Is that not the case, because I did not seem to come close.

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You left behind 4 gallons on your first batch, which comes to 0.12 gal/lb. Could be a little dead space, or maybe you had quite a few flaked grains in the grist. They absorb more, but overall you're right in the ballpark. Sounds perfect so far.

After that though I'm not convinced you're sparge wasn't sticking. I've never continued to accumulate losses like that. What kind of manifold or braid are you using? A heavy dose of flaked grains could explain this, too.