Batch Sparge Gravities - Home Brew Forums

Register Now!
Home Brew Forums > Home Brewing Beer > Brew Science > Batch Sparge Gravities

Reply
 
Thread Tools
Old 08-12-2010, 03:07 PM   #1
AnOldUR
fer-men-TAY-shuhn
HBT_LIFETIMESUPPORTER.png
 
AnOldUR's Avatar
Recipes 
 
Mar 2007
, New Jersey
Posts: 6,886
Liked 844 Times on 609 Posts



I've been looking over Kaiser posts but can't figure out the answer to this.

It there a way to figure out the gravity of each running in a batch sparge?
The decline in gravity must follow some sort of curve.

Say my first runnings and two batch sparges are all equal volume and I knew that my total pre-boil wort gravity was 1.042. Using a half-life assumption I'd get:

First Runnings = 1.072
First Batch Sparge = 1.036
Second Batch Sparge = 1.018

That's guessing that each running has half the gravity as the one before, but that is just a guess. Anyone know what that number actually is?

 
Reply With Quote
Old 08-12-2010, 03:19 PM   #2
prosper
Recipes 
 
Oct 2009
Edmonton
Posts: 477
Liked 1 Times on 1 Posts


it greatly depends on your system - the amount of dead space in your tun, for example. In my system, for an 'average' gravity recipe, I get approximately 85-90% of my sugars in the first runnings, at a mash thickness of about ~2.5qt/lb - i.e. when I 'no-sparge' by adding in the sparge water before beginning the runoff, my overall efficiency goes down by 10 or 15%

 
Reply With Quote
Old 08-12-2010, 03:55 PM   #3
AnOldUR
fer-men-TAY-shuhn
HBT_LIFETIMESUPPORTER.png
 
AnOldUR's Avatar
Recipes 
 
Mar 2007
, New Jersey
Posts: 6,886
Liked 844 Times on 609 Posts


What I'm looking for is a constant in the decline of gravity over a series of lauters that would be proportional to your efficiency (and system), but not dependent on it. I would think it would be contingent on the grains ability to hold sugar from one lauter to the next.



Edit:
It's probably effected by the type of grain and the crush, but I was hoping that some generalizations could be made.

 
Reply With Quote
Old 08-12-2010, 04:03 PM   #4
prosper
Recipes 
 
Oct 2009
Edmonton
Posts: 477
Liked 1 Times on 1 Posts


that, in turn, would be dependent on your system, though, would it not? How fine you crushed, how long you let it rest between run-offs, possibly the temperature, whether or not you used a mash-out, whether or not you stir your mash, the geometry of your mash tun (the weight of the column of grains could wring out more sugars).

Such a constant would therefore only be applicable to the system it was measured on, assuming that consistent processes were followed brew after nrew

 
Reply With Quote
Old 08-12-2010, 04:09 PM   #5
Revvy
Post Hoc Ergo Propter Hoc
HBT_LIFETIMESUPPORTER.png
 
Revvy's Avatar
Recipes 
 
Dec 2007
"Detroitish" Michigan
Posts: 40,921
Liked 3184 Times on 1883 Posts


There are some generalizations made for each sparge round, at least in information I've come across for partyguilling purposes. I remember coming across it when I did that pumpkin partigyle a couple years back.

IIRC the numbers are mentioned in some of the links in my old thread http://www.homebrewtalk.com/f36/lets...ne-mash-74927/ I tihk it's in Randy Mosher's article;

http://www.brewingtechniques.com/lib....2/mosher.html

There's some tables there it may give you a rough guestimet, or at least help you figure out how to get that guestimate.
__________________
Like my snazzy new avatar? Get Sons of Zymurgy swag, here, and brew with the best.

Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman

I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew

 
Reply With Quote
Old 08-12-2010, 04:19 PM   #6
Revvy
Post Hoc Ergo Propter Hoc
HBT_LIFETIMESUPPORTER.png
 
Revvy's Avatar
Recipes 
 
Dec 2007
"Detroitish" Michigan
Posts: 40,921
Liked 3184 Times on 1883 Posts


This table may help. It give the breakdown of each round based on the OG of the total, but it does it for a 1/3 + 2/3 split or a 50/50 split in partyguile batches.

http://www.brewingtechniques.com/lib...shertable.html
__________________
Like my snazzy new avatar? Get Sons of Zymurgy swag, here, and brew with the best.

Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman

I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew

 
Reply With Quote
Old 08-12-2010, 05:07 PM   #7
AnOldUR
fer-men-TAY-shuhn
HBT_LIFETIMESUPPORTER.png
 
AnOldUR's Avatar
Recipes 
 
Mar 2007
, New Jersey
Posts: 6,886
Liked 844 Times on 609 Posts


Great stuff Revvy! It looks like the half-life estimate holds close to true. It's right there on the 1/2 -1/2 split chart and close on the numbers that Mosher comes up with when doing three equal runnings. Thanks.

My simplified math for three runnings went like this:

AG = Average gravity of entire batch
BC = Batch constant

BC = 3 * AG / 7

Gravity of 1st sparge = 4 * BC
Gravity of 2nd sparge = 2 * BC
Gravity of 3rd sparge = BC
(w/ three equal sparge volumes)


Quote:
Quote Mosher:
Thus, a 16 P entire batch will yield 5 gal of beer at 24 P, 5 gal at 16 P, and 5 gal at 8 P. Actual gravities will vary from batch to batch, depending on many factors; these estimates provide a starting point only.

 
Reply With Quote
Old 08-12-2010, 05:11 PM   #8
AZ_IPA
PKU
HBT_LIFETIMESUPPORTER.png
 
AZ_IPA's Avatar
Recipes 
 
Jun 2008
The Cold Part of AZ
Posts: 52,382
Liked 8614 Times on 6927 Posts


I charted a few of my brews, and they dropped ~50% from mash runnings, 1st sparge, 2nd sparge...


 
Reply With Quote
Old 08-14-2010, 03:29 PM   #9
Tom
Recipes 
 
Feb 2005
Denver
Posts: 112
Liked 1 Times on 1 Posts


That's been my experience too. ~ 50% each step.

 
Reply With Quote
Old 08-14-2010, 04:15 PM   #10
david_42
 
david_42's Avatar
Recipes 
 
Oct 2005
Willamina & Oak Grove, Oregon, USA
Posts: 25,593
Liked 151 Times on 142 Posts


The last batch I checked was 46%, 30% and 24%

 
Reply With Quote
Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Why not just add all sparge water if the cooler is big enough? norwegiangeek Brew Science 26 01-05-2011 05:46 PM
Does TH's SpreadSheet Dilution Inc. Sparge? Netflyer Brew Science 3 02-26-2010 06:28 PM
mash ratio for no-sparge JLem Brew Science 14 11-20-2009 07:11 PM
Mash and Sparge PH Issues JamieT Brew Science 5 11-01-2009 06:31 PM
Excerpt on Sparge = Really? GilaMinumBeer Brew Science 8 03-12-2009 12:52 PM


Forum Jump