Batch sparging high gravity beers

A recent and excellent thread by RichBrewer (https://www.homebrewtalk.com/showthread.php?t=30466) got me re-thinking batch sparging for high gravity beers.

In his list of advice, Rich suggests that at least 3 quarts of brew water per pound of grain is required to optimize efficiency (i.e., 1 to 1.25 qt/lb for mash and an additional 2 qt/lb for sparging). Obviously, for a high gravity brew, the large amount of grain necessitates a considerable amount of water, perhaps even more than can be accommodated in one's kettle.

I have basically followed this formula for some of my lower gravity beers with great success. But my last brew was fairly high gravity (1.0787) and I definitely had lower efficiency (dropped about 10%) which I thought was a temperature problem, but now I am thinking it was because I had too little sparge water (now I really wish I had taken the gravity of my second runnings! – oh well, I bought a refractometer so no excuse now). Anyway, I have the capacity to boil a large volume (up to 15 gal), but I don't really want to be boiling for 2-3 hours.

So, my question is whether anyone knows of a method to estimate the loss in efficiency that one can expect if you want to brew a high gravity beer but use less water than Rich suggests above. I expect that the loss in efficiency will be related to the gravity of the beer since I want to keep my boil time (and hence, the volume of runnings) fixed, and the higher the gravity and the more grains that are used, the greater the shortcoming of water and lesser the efficiency. I pursued batch sparging because it seemed quick and easy, and I wasn't afraid to add a little extra grain to my mash to compensate for any loss in efficiency. I would like to follow the same principle here, if possible, when mashing large amounts of grain yet keep my boil volume consistent. All that's needed is a method to calculate the additional grains to compensate. Any ideas? Thanks.

Oh, I should also mention that I have fiddled with Beersmith and Promash -- if they perform these calculations, I wasn't able to figure out how to do it. I am guessing that they weren't designed to do this.

I use http://hbd.org/cgi-bin/recipator/recipator and you have to change the efficiency percentage, then manually adjust the base malt until you are back to the desired gravity.

You might consider (if you have the room) doing a heavy ale from the first runnings (or first and part of the second) and a small beer from the second and third.

david_42 said:

You might consider (if you have the room) doing a heavy ale from the first runnings (or first and part of the second) and a small beer from the second and third.

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Good idea! You will definitely have enough sugars left in the wort to make a good smaller beer. This is the way they did it in England hundreds of years ago.

With ProMash, can you simply play with the efficiency setting in the recipe window to compensate for the lower efficiency?
For instance, if I'm shooting for a 1.100 wort for 75% efficiency I would need about 18 pounds of grain. If I lower the efficient to 60% I have to bump the grain up to 22.5 pounds. I guess you would have to experiment to know exactly how much efficiency you would lose so it might take a couple brews to figure it out.

RichBrewer said:

With ProMash, can you simply play with the efficiency setting in the recipe window to compensate for the lower efficiency?
For instance, if I'm shooting for a 1.100 wort for 75% efficiency I would need about 18 pounds of grain. If I lower the efficient to 60% I have to bump the grain up to 22.5 pounds. I guess you would have to experiment to know exactly how much efficiency you would lose so it might take a couple brews to figure it out.

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Yes, precisely. But I guess what I was really wondering is there a way to PREDICT how low your efficiency will be if you short-change the sparge water ? If you knew this, one could figure out how much grain to add to compensate.

I am guessing the answer is no, and that it will take some trial and error.

I'm curious about this as well, but it sounds like you've got a good estimate to go by (10% for a beer of that magnitude). I'm planning on a long boil for my biggie coming up, and since the Banjo Cooker kicks out so many BTUs, I can get plenty of evaporation so I can collect a lot more wort than I usually would.

I'm also really temped to try and set up a fly-sparge setup to squeeze a few more points of efficiency. I have an extra cooler I could use as a HLT, and extra copper I could fashion into a sparge arm, but then I'm worried about PH. Not wanting to hijack, but can you use the PH 5.2 Buffer in the sparge water and not have to worry about PH during the sparge? Or doesn't it work that way?

FlyGuy said:

Yes, precisely. But I guess what I was really wondering is there a way to PREDICT how low your efficiency will be if you short-change the sparge water ? If you knew this, one could figure out how much grain to add to compensate.

I am guessing the answer is no, and that it will take some trial and error.

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I think you're right on the trial and error...I think I could probably do this for my system, b/c (when I fly sparge) I take SG readings every 1/2-gal once I get to 5 gallons of runoff. Not sure how you'd guess if you're batch sparging, though I guess some sort of similar experience-based "regression" might work.

Take and educated guess...you can always adjust by adding water, DME, or adjusting boil time/batch volume.

My educated guess (looking at my past notes) would be that for every gallon I go below 0.5 gal/lb of sparge water, I lose ~3-5% efficiency

Thanks everyone -- that's a good starting point.

I do a lot of statistical analysis for my job, so maybe I will start taking more precise notes on these things and figure it out. Alternatively, if anyone wants to 'donate' their brew notes, perhaps I could work up some analyses and figure out a statistical regression model.

the_bird said:

I'm also really temped to try and set up a fly-sparge setup to squeeze a few more points of efficiency. I have an extra cooler I could use as a HLT, and extra copper I could fashion into a sparge arm, but then I'm worried about PH. Not wanting to hijack, but can you use the PH 5.2 Buffer in the sparge water and not have to worry about PH during the sparge? Or doesn't it work that way?

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Don't see why the 5.2 wouldn't work that way...I just started using it, and I add it to all my mash/sparge water. Didn't make sense to me to be all worried about pH durng the mash, and then let it go wherever during the mash.

Also, I thought I read somewhere (Papazian, maybe) that sparge pH and SG of the runoff were pretty well correlated, and as long as you stopped when runnings were 1.006-1.008 you'd be OK. That's why I read the SG every half-gallon when I get close to my target volume. Never come really close, b/c I don't push my efficiency that hard, but I still do it out of habit.

This may sound stupid but... Is there a reason that you couldn't sparge with your first wort, like heat it back up to temp and batch sparge to obtain a higher gravity with the same amount of wort. I'm sure there is a reason not to but I don't know what it is.

NewBrewer25 said:

This may sound stupid but... Is there a reason that you couldn't sparge with your first wort, like heat it back up to temp and batch sparge to obtain a higher gravity with the same amount of wort. I'm sure there is a reason not to but I don't know what it is.

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Just guessing, but I think you need the sparge water to have a lower sugar concentration than the grain bed to get good extraction. So re-running the first wort might not extract that much more sugar.

Bike N Brew said:

Just guessing, but I think you need the sparge water to have a lower sugar concentration than the grain bed to get good extraction. So re-running the first wort might not extract that much more sugar.

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I have seen some techniques which seem to indicate you can use first runnings as sparge water but I'm guessing it won't increase the gravity of the runnings much. If you are sparging correctly, you are getting the maximum amount of sugars out of the grains you are going to get with the current water. Basically the concentration of sugar should be equal throughout the mash (water and grain). To make a bigger beer with less water you are going to stop the runnings with a higher gravity (greater concentration of sugar) which means more sugar is left in the grains.
I think this is also why batch sparging is usually less efficient than fly sparging. The last draining of a batch sparge has a higher gravity than the last runnings during fly sparging.
Craig

NewBrewer25 said:

This may sound stupid but... Is there a reason that you couldn't sparge with your first wort, like heat it back up to temp and batch sparge to obtain a higher gravity with the same amount of wort. I'm sure there is a reason not to but I don't know what it is.

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As noted above that won't help much at extracting more sugar from the original mash. You can, however, use the wort to mash another batch of grain for when brewing really high gravity beers and your equipment or boil volumes are limiting.

So the difference in sugar content between the first runnings and the mash is too close to extract more sugar. Is there a relationship between color of the wort exiting the mash tun and the amount of sugar in it?

NewBrewer25 said:

So the difference in sugar content between the first runnings and the mash is too close to extract more sugar. Is there a relationship between color of the wort exiting the mash tun and the amount of sugar in it?

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Not necessarily, because the color often comes from dark roasted grains that may not be contributing much by the way of sugar in the mash.