Steve973

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Lately, my brewing buddy and I have been making high gravity (Belgian) beer. On Sunday, we mashed 14 pounds of pilsener malt in 21 quarts of water, which comes out to 1.5 quarts/pound. We seem to have efficiency isses when doing this. I think the problem arises from too much water in the mash, which takes away from sparge water volume, so some sugars get left behind. We're trying to mash for attenuation, so we mash with lots of water at lower temperatures. We recycle until the runnings are clear, then drain the wort off of the grain until we have between a half-inch and an inch of wort above the grain bed, and then we begin sparging. For a 5 gallon batch, we didn't need too much sparge water before we obtained our pre-boil target volume. With the pils malt and 2 lbs of candy sugar, our OG turned out to be 1.084 which doesn't sound too bad until you realize that we were shooting for 1.096 for 75% efficiency. Our efficiency was 63%, and we'd like to improve. Any ideas, or can anybody point out a major flaw in our procedure? Thanks in advance!

Brewsmith

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If you use a ratio of 1 qt/lb there will be more room for sparge water. Also, be prepared to sparge with more water than normal to rinse the grain better. Then increase the boil time to bring the batch back to the normal size.

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Steve973

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That sounds good. We'll definitely try 1 quart/gallon next time. I wonder how this will affect attenuation ability. Does everyone think it'll be thin enough for a more attenuable mash?

ScottT

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Yes, the concentrated mash will incerase the density of enzymes and can speed up the conversion. Just make sure you stir it well to avoid any dry spots and be sure to double check that your temp has setteled at the target temp. Remember that less strike water will require a higher temp to attain your desired mash temp due to the heat sink of the grain.

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Alvin

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Steve973 - What batch volume are you brewing? By my mash calculations you could get a maximum gravity of 1.097 from 14 lbs of Pilsener malt in a 19 litre / 5 U S Gal batch. 1.084 /1.097 is about 86% by my calculations. I assume that you are fly sparging; how fast are you sparging and how much wort volume are you collecting for the boil?

sebbeerbiker

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I agree with Alvin, your mash extraction will vary a lot depending on how fast you drain/sparge. Changing the water to grist ratio to a thicker mash will affect the fermentables so I wouldn't change that necessarily. You could try fly sparging very slowly (less than 1qt per minute) or drain the MT completely, refill with hot water to the top of the grain bed to refloat it, and restart your sparge.

A good extraction of 30pts/lb of grain (around 90% eff.) is quite attainable. So with your 14 lbs of grain, you would expect 5 gallons of 1.084 wort, before even adding the sugar.

Seb

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DeRoux's Broux

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steve, try just recirculating for 20 minutes, then start draining to the mash tun and sparging w/ 170-175 degree water. do the recirculation and sparge very slow. a sparge for a big beer should take 90 - 120 minutes. make sure you hit your saccharification rest temp, and mix the grain and stike water well to eliminate any dough balls.
or, you could follow janx's advice. if your efficiency is low, add more grain! :~)

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Steve973

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Thanks for the replies, everyone. We were brewing a 5 gallon batch in one of the 10 gallon yellow rubbermaid coolers with a bazooka tube in the bottom. I assume that we recirculated for about ten minutes before starting to drain the wort. I don't consider that part "sparging" because we're not adding clear hot water to the top at this point, just draining it down until it nears the top of the grain bed. Then we sparged. I don't know how long we could try to sparge a gallon or two, but we'll try stretching it out next time. With so much water in the mash, it doesn't feel like we could get a proper sparge. Any suggestions for that? We gathered about 6.5 gallons before the boil.

Steve973

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By the way, Alvin, we obtained 1.084 only after adding the candy sugar, so our efficiency is bad. I might try using a larger amount of sparge water next time, and use our old (smaller) mash cooler to hold the water so it stays hotter...

sdent

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Is there a benefit to recycling the wort back through the grain bed after the sparge? How about heating the wort up to 170 F and then recycling it through? Would that increase extraction efficiency?