Strange volume for my partial mash

[nickmv]

I'm doing a partial mash IPA, batch size 5.25 gal (1.064 OG).

I'm using BeerSmith to work out the numbers, and I'm a bit confused about volumes. I'm doing a full boil (minimal to no topoff afterwards).

I'm using approx 4lbs of grain (not counting DME), and BS tells me to add 5.2 qt (I'm using 1.3qt/lb) for mash, 60 min.

Now here's where it gets weird. It tells me to sparge with 6.21gals!!! That's 3x more than what I expected. Typically, from what I've read, you sparge with around .5gals/lb of grain. With 4lbs of grain, that works out to 2gals of water.

This leads me to a series of questions:
1) Regardless of sparge vol, is BeerSmith even correct on total vol? I'm estimating a 6.78gal pre-boil for my setup. 5.21qt+6.21gal = roughly 7.5gals. Is that calculation taking into account vol lost to grain in addition to boil-off?

2) Is the sparge volume correct? Again, I've followed .5gals/lb, and then topped off to est pre-boil volume from what I recall. I figure that's what I should do.

 

[bluemoose]

My suggestion would be to sparge with a volume that will bring you to your total boil volume less the DME. If you have a room in your kettle and are not topping off figure about a total of 6.25 gal. IMHO it will be better to use sparge water than to add fresh to the brew kettle to make up the difference. The loss to boiling is going to depend on your kettle.

 

[nickmv]

I have an 11gal Bayou Classic kettle, so I've got plenty of room. Now when you say sparge to total less the DME.....is there a way to determine vol occupied by DME? Also, doesn't oversparging lead to tannin extraction?

The way I figured, I'd heat up the rest of the water, but only use ~2 gals to sparge, then pour the rest in as a top-off preboil.

 

[jculler82]

Beersmith just uses the calculated boil volume and subtracts the volume it estimates you'll get in first runnings, then calls that the needed sparge water.

You are correct in that you can sparge with 2 gallons (or more, or less if you want) and top up with the rest of the water and add your DME.

 

[dcp27]

grain absorbs about 0.12 gallons / lb, so the sparge amount really isnt that far off to get your pre-boil amount. however, sparging too much can extract tannins so just go with your 2 gallon sparge and just add the rest. IIRC, extract adds about 0.1gals/lb, so don't forget to account for that.

 

[nickmv]

dcp, is that for LME or DME? I'm working with DME, if it makes a difference. That's the only figure I need to work out, and then I should be set.

 

[jculler82]

If you're adding all your DME for the full boil, you could top up to a gallon or more less than you want, add your DME, then top up the rest of the way if needed.

 

[nickmv]

I thought about this, and the only concern I had was if adding the DME before the boil begins has any effect. I'm probably being paranoid there. I usually get a boil going, flameout, add DME and mix it in, then resume boil. I'll prob just add it after I sparge.

 

[jculler82]

Whatever you're comfortable with. I think dcp's calculations were for DME and not LME. For what it's worth, I've always added the DME while bringing the water to a boil and haven't had any problems.

 

[dcp27]

dcp, is that for LME or DME? I'm working with DME, if it makes a difference. That's the only figure I need to work out, and then I should be set.

from a quick google search, it sounds like its about 0.075 gallons/ lb DME, and 0.085 for LME

 

[nickmv]

from a quick google search, it sounds like its about 0.075 gallons/ lb DME, and 0.085 for LME

I must be doing bad Google searches, because I couldn't find any figures for it. It's been a long work-day....

Anyways, thanks for all your responses. I think I'm all set. Besides, brewing wouldn't be fun if everything goes as planned anyways!