### Author Topic: krausen equation  (Read 1514 times)

#### yaleterrace

• 1st Kit
• Posts: 11
##### krausen equation
« on: November 20, 2010, 09:35:35 AM »
Can anyone help me out with a real and accurate krausen equation?  I brew ales and would like to bottle and keg referment without the use of refined sugar.  I would be adding unfermented wort to a fully fermented batch, none of the potentially more complicated lager techniques.  I found the following formula, but I';m not sure it's what I need:

Vp/Vb = SGb/SGp x Cv/(2.44 x SGb x SGp x F - Cv)

#### hokerer

• I spend way too much time on the AHA forum
• Posts: 2628
• Manassas, VA
##### Re: krausen equation
« Reply #1 on: November 20, 2010, 09:37:37 AM »
Kai's got a pretty good explanation of krausening on his wiki site...

http://braukaiser.com/wiki/index.php/Kraeusening
Joe

#### denny

• I must live here
• Posts: 10736
• Noti OR [1991.4, 287.6deg] AR
##### Re: krausen equation
« Reply #2 on: November 20, 2010, 10:05:22 AM »
I predict that after you try it a couple times, you'll go back to sugar.  I did....
Life begins at 60.....1.060, that is!

www.dennybrew.com

The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

#### yaleterrace

• 1st Kit
• Posts: 11
##### Re: krausen equation
« Reply #3 on: November 20, 2010, 10:33:51 AM »
The math is definitely advanced enough that I'm not a happy camper, but I happen to be friends with a mechanical engineer who specializes in fluids, so I'll pay him in beer to help me drop the whole thing into a spreadsheet.  I really would like to get away from adding sugars and nonsense, to keep the numbers exact for ABV and such, and to keep the beer clean from refined ingredients or preservatives.  We'll see, I guess!

#### denny

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• Noti OR [1991.4, 287.6deg] AR
##### Re: krausen equation
« Reply #4 on: November 20, 2010, 10:49:01 AM »
I felt like that at one point.  I think I tried priming with gyle about 3 times before I gave it up as inexact and showing no flavor benefits over using sugar.  I think you're fooling yourself that you'll get more exact ABV measurement, too.
Life begins at 60.....1.060, that is!

www.dennybrew.com

The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

#### jaybeerman

• Guest
##### Re: krausen equation
« Reply #5 on: November 20, 2010, 10:49:41 AM »
I predict that after you try it a couple times, you'll go back to sugar.  I did....

I haven't tried krausening yet; did you quit due to unpredictability? I read a quote this week that I think applies to brewing.
"In theory, there is no difference between theory and practice. But, in practice, there is." (That's Jan L.A. van de Snepscheut, supplied by Quotes Of The Day)  I actually hate that quote though I know it contains truth; there are some cool techniques that really aren't that practical in the long run.  That said I'm still going to give it a whirl at least a couple times.

#### jaybeerman

• Guest
##### Re: krausen equation
« Reply #6 on: November 20, 2010, 10:54:24 AM »
The math is definitely advanced enough that I'm not a happy camper, but I happen to be friends with a mechanical engineer who specializes in fluids, so I'll pay him in beer to help me drop the whole thing into a spreadsheet.  I really would like to get away from adding sugars and nonsense, to keep the numbers exact for ABV and such, and to keep the beer clean from refined ingredients or preservatives.  We'll see, I guess!

I would send you a very simple spreadsheet for free, but you already threw it out there that you were willing to pay with beer    Seriously though if you pm me I will send you a spreadsheet (maybe monday i'll have time.  I'm about to take the kid bowling)

#### denny

• I must live here
• Posts: 10736
• Noti OR [1991.4, 287.6deg] AR
##### Re: krausen equation
« Reply #7 on: November 20, 2010, 10:54:47 AM »
I predict that after you try it a couple times, you'll go back to sugar.  I did....

I haven't tried krausening yet; did you quit due to unpredictability? I read a quote this week that I think applies to brewing.
"In theory, there is no difference between theory and practice. But, in practice, there is." (That's Jan L.A. van de Snepscheut, supplied by Quotes Of The Day)  I actually hate that quote though I know it contains truth; there are some cool techniques that really aren't that practical in the long run.  That said I'm still going to give it a whirl at least a couple times.

Partially unpredictability, but mainly because it was more effort for no appreciable benefit.  If I'm gonna do more work, there damn well better be a payoff for it!  But I encourage you to try it and form your own opinion.  As to not wanting to use sugar, if that was a concern I'd have to stop brewing Belgian beers!
Life begins at 60.....1.060, that is!

www.dennybrew.com

The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

#### jaybeerman

• Guest
##### Re: krausen equation
« Reply #8 on: November 20, 2010, 11:03:46 AM »
Partially unpredictability, but mainly because it was more effort for no appreciable benefit.  If I'm gonna do more work, there damn well better be a payoff for it!  But I encourage you to try it and form your own opinion.  As to not wanting to use sugar, if that was a concern I'd have to stop brewing Belgian beers!

I hear ya on the payoff part.  My thing is that I'm kegging all my brews (ultra simple) but I wouldn't mind trying the technique out for the brews I plan on storing for very long periods of time (e.g. Barley Wine, Imp Sout, Braggot, etc).  Yeah I don't have the sugar phobia either.

#### euge

• Official Poobah of No Life.
• Posts: 6730
• Estilo Casero
##### Re: krausen equation
« Reply #9 on: November 20, 2010, 12:04:27 PM »
I think it makes sense if you have a brewery operation going cranking out the beer daily. A constant supply of active yeast and fresh wort and a nailed down procedure.

At the homebrew level it becomes a matter of expediency. I guess one could just prime with extract or build a "priming starter" and add that to the keg or bottling bucket?

And per Kai's write-up you still might have to add sugar anyway.
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

#### tubercle

• Senior Brewmaster
• Posts: 1639
• Sweet Caroline
##### Re: krausen equation
« Reply #10 on: November 20, 2010, 02:19:02 PM »
Tubercle's 0.02...

1. If you add unfermented wort you are adding "sugar",  just a different type than corn or table.

2. Corn or table sugar is very predictable since it is 100% fermentable for practical purposes. Unfermented wort is a mixture of highly fermentable simple sugars and complex sugars that may or may not ferment over time. To predict the outcome you need to know what this mixture is.

3. Stick with table sugar.
Sweet Caroline where the Sun rises over the deep blue sea and sets somewhere beyond Tennessee

#### lonnie mac

• Assistant Brewer
• Posts: 180
##### Re: krausen equation
« Reply #11 on: November 20, 2010, 02:33:18 PM »
I could never try this anyway. What this gibberish means is way beyond me!

#### yaleterrace

• Cellarman
• Posts: 27
##### Re: krausen equation
« Reply #12 on: November 20, 2010, 03:07:37 PM »
you posted the metric equation for starters...

#### yaleterrace

• Cellarman
• Posts: 27
##### Re: krausen equation
« Reply #13 on: November 20, 2010, 03:21:09 PM »
Okay, so now everyone has the background (didn't want to get into all this):
I am brewing 10 - 15 gallon batches every 7 - 10 days (not exceeding more than 200.00 gal/yr) so I have the capacity to store and reincorporate unfermented wort.  Given that overall ambient fermentation room temperature in my home changes only +/- 5 degF per ale fermentation cycle (seasonally), I am not concerned about conditional variables as far as the differences for the gyle refermentation is concerned.  I would also like to eliminate the use of refined sugar us in my processes.  (So I take pride in turning malted barley into sugar.  So what?)  As it is now, I have almost exclusively employed dextrose as a refermentation fermentable, but recently having acquired the total apparatus for kegging multiple batches, I am not so fond of the mouthfeel of my force-carbonated batches.  Also, as I understand it, the alcohol content can be determined much more accurately with gyle refermentation since the total fermentable component of the wort is identical between the original batch and the gyle, and since fermentation has ceased post secondary fermentation, I will know the exact fractional fermentability between OG and FSG.  This means I can create a beer with no processed sugar extracts, naturally ferment it, and do so with relative ease once I can wrap my head around some numbers.  Worth it to me.

#### lonnie mac

• Assistant Brewer
• Posts: 180
##### Re: krausen equation
« Reply #14 on: November 20, 2010, 03:36:35 PM »
Lot's of folks have tried this myself included.

I do have to say this though... As you stated "I am not so fond of the mouthfeel of my force-carbonated batches."

Well, that's a recipe problem then. Nothing more... If you don't like the mouthfeel, you can take care of that in the recipe. The carbonation has nothing to do with that issue other than to tell you that you have a recipe problem and you should take care of that on the front end... I couldn't brew a beer, and rely on my mouthfeel coming from bottling alone. I brew almost as much as you do, sometimes more, sometimes less... There is no way I can bottle all that beer my friend! I gotta keg!