Krausening Formula

[kymba]

i'm such a tightwad that the idea of karausening really gets me excited

so what i want to do is keg my beer 1 degree plato before FG so the remainder of the fermentation naturally carbs my keg without using dex or sugar

therfore, given an OG and the expected FG, how do you work out the ADJUSTED refractometer reading required to keg the beer 1 degree out?

edit: i am a mathtard so pls go easy

 

[Florian]

If play around in beersmith or any other refractometer tool you basically want your Sg reading about 4 points (1 degree Plato) out from your final, so if you have a play around it wouldn't be hard to figure out the adjusted reading, depending on OG.

As an example, if your OG is 1.050 and your anticipated FG is 1.010 (6.3 Brix adjusted reading) and you want to transfer 4 gravity points before 1.010 (so at 1.014) then you should transfer when your refrac reads 7 Brix.

Hope that helps, just figured it out myself, never actually done it this way, but seems logic to me right now.

Are you sure your 1 degree will give you enough carbonation? Not entirely sure but I would've thought you might need a little more, depending on carb level of course.
I have one of these, but to be honest haven't used it much yet, only twice, and not entirely sure yet if I can recommend it or not.

 

[kymba]

seems i got all my shit mixed up, and what i want to do is called spunding...krausening is where you use kept-aside or even fresh wort to prime your bottles or kegs

here is the best quote i could find on the matter from the kaiser:

For each % or Plato of real extract you get 0.5% w/w CO2 since we assume that 1 g of sugar ferments to 0.5 g of CO2 and 0.5 g of ethanol.

With that and some more conversions I get the following rule of thumb:

each gravity point gives you about 0.5 volumes of CO2 and each degree Plato gives you about 4 g/l CO2.

This goes along with the observation that priming adds about 3 points, which equals 1.5 volumes CO2 and the remaining 1 volume is assumed to be already in the beer.
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from here http://www.homebrewersassociation.org/foru...hp?topic=2177.0

and here is a byo article on building a spunding valve http://www.byo.com/stories/projects-and-eq...nate-in-the-keg

doesn't help me with the adjusted refractometer reading though so i'll just have to look 4 points higher on my correction chart - how archaic