Home Brew Forums

Home Brew Forums (http://www.homebrewtalk.com/forum.php)
-   All Grain & Partial Mash Brewing (http://www.homebrewtalk.com/f36/)
-   -   The CORRECT Batch Sparge Volume? (http://www.homebrewtalk.com/f36/correct-batch-sparge-volume-36011/)

Evan! 08-10-2007 01:52 PM

The CORRECT Batch Sparge Volume?
 
I've been mashing for awhile now, and I usually just wing it on the sparge volume. Not too smart, I know, but it's turned out okay so far. The major drawback, though, is that I can't adequately judge my pre-boil volumes prior to the brew session.

So, someone please fill me in on the correct sparge water volume for batch sparging. My Mephistopheles mashes in in less than 24 hours:

15.5 lbs of grain

19.06 qts of strike water

______ qts of sparge water

...what's the equation for determining that last number...? I learned mashing from Papazian, and his recipes always had specific sparge amounts, but never explained the equation so I could do it on my own. Thanks...:mug:

Jester 08-10-2007 02:07 PM

I'd be interested in knowing this also... Thanks..

Jester

the_bird 08-10-2007 02:16 PM

Two variables you need. The first is the grain absorption rate. I've seen it estimated at 0.1 gallons / pound, but that always left me short, so I've been doubling that assumption and getting pretty close to right.

The second depends on your system; what kind of dead space do you have in your mash tun? With the Coleman Xtreme, I'm essentially at zero deadspace; for others, that's upwards of a half gallon. Since that's different for everybody, there is no one "right" answer.

perry 08-10-2007 02:18 PM

I may be missing something in your process, but my suggestion is to simply sparge until you have two gallons over your target batch size. Back before I had my system figured out, I sometimes had to heat small quantities on the stove to get the tright amount. Now, If I'm doing a five gallon batch, I heat five gallons of sparge; if I'm doing ten, I heat ten. This leaves me with a couple of quarts left over, but that's ok.

Oh, I fly sparge, but amounts for batch sparging should be similar.

Hope this is helpful.. -p

david_42 08-10-2007 02:19 PM

The volume of sparge water is the same batch or fly, so any of the calculators will work.

Figure you'll get 100% of the first sparge back, so I drain and add the same volume as I used for mashing. Then I measure the first runnings and adjust the second sparge volume.

FlyGuy 08-10-2007 02:27 PM

Dude - you are NOT going to like some of the answers you receive.

Do you like long boils? Low efficiency? Over-flowing mash tuns or boil kettles?

I don't think there is a right answer to this. My belief is that big beers are often harder to brew, and it is all about trade-offs. A good rule of thumb is to sparge with 1 to 2 volumes of your mash water, depending on the thickness of your mash. I think RichBrewer was suggesting about 2 qts per pound of grain is optimal. So your total water becomes something approaching 1 gallon per lb of grains. For a 15 lb batch, thats about 12 - 15 gallons of water to deal with, to be optimal.

The trade-off is that you can sparge with less water to get your boil volume down, but that will hurt your efficiency. Unfortunately, I haven't seen any good correction formulas that will allow you to predict the amount of loss in efficiency. I would guess that for your grainbill, if you collect 7 gallons of wort, you could expect a good 10% drop in efficiency because your sparge water-to-grain ratio has dropped so much, by comparison to a typical batch.

The good news is that you are already planning to add some DME -- best to have some extra on hand too. And it would be a good idea to check your SG before the boil and calculate your efficiency. If you really under-shoot, that is going to affect your hop utilization, which may need correction, too.

Hope the brew goes well -- looking forward to hearing about it! :mug:

EDIT: Just ran some numbers on 15.5 lbs of grain, and I guess it isn't that big (duh -- was deluded by your OG -- forgot this was actually a 'partial mash'). Just sparge to reach your boil volume, and you might take a few points hit on your efficiency if you are used to brewing with less grain, say only 10lbs per batch.

Evan! 08-10-2007 02:54 PM

Okay, well, I'm designing my mash right now...I think about 7 gals would work for my sparge volume. If I split my wort into two kettles boiling side-by-side, what do you think my evap % rate per hour will be?

Looks like, to get down to 4.5 gals, I'm going to need to boil this bastard for-f*cking-ever. Damn.

I guess what I'll do is, since I'm going to be adding the LME late in the boil anyway, I'll just check my SG at 15 mins before flameout. If I need to add any extract at that point, I'll do it.

the_bird 08-10-2007 02:57 PM

Quote:

Originally Posted by Evan!
If I split my wort into two kettles boiling side-by-side, what do you think my evap % rate per hour will be?

Isn't the humidity level like 98% down in Virginia right now? That has a huge impact on evaporation rates (as well as total surface area, etc).

Prepare for a LONG boil, my friend.... :D

Evan! 08-10-2007 03:01 PM

Quote:

Originally Posted by the_bird
Isn't the humidity level like 98% down in Virginia right now? That has a huge impact on evaporation rates (as well as total surface area, etc).

Prepare for a LONG boil, my friend.... :D

Yeah, I do believe I could swim out my window right now if I wanted to.

Ugh. Well, good thing I don't have anything else to do. But I'll probably wake up at 5 just to get a nice head start. So do you have any ideas on the evap rate numbers? Just so I can plug it into ProMash...?

tst4echo 08-10-2007 03:02 PM

Easy rule of thumb is 1/2 your grain volume. Brewing software also helps to work out some of the specifics, but this has always worked for me.


All times are GMT. The time now is 06:22 AM.

Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.