Is there a simple rule of thumb for the level of carbonation achieved if one ferments for awhile in primary and then transfers (before FG is reached) to the keg or the bottle?
For example, given a beer with an OG of 1.070 and assuming a FG of 1.010 as our goal (perhaps even determined by FFT), how many volumes of CO2 could one expect if I filled a 12 ounce bottle with:
1.015 SG beer
1.020 SG beer
1.025 SG beer
1.030 SG beer
1.035 SG beer
1.040 SG beer
How about a 5 gallon Corny keg?
Is there a simple rule of thumb for remaining SG points to be fermented and levels of CO2 produced?
Does some allowance need to be made for pre-existing CO2 levels in beer that is being racked/bottled from the fermenter?
Thanks for the links, but Kai might as well be writing in wingdings. ???
It’s too complex for me.
I’m looking for a “simple rule of thumb” that doesn’t require a calculator (e.g., one “brix” = 4 “gravity points”)
The calculations look pretty straightforward. He’s saying you’ll add 0.5% CO2 for every degree Plato of additional attenuation. Since 0.5% CO2 is about 2.5 vol, you need 0.4°P of attenuation (about 1.6 points) for every volume of CO2 you want to add.
With all due respect to Malamallotary5 and Rofikss69, this question isn’t about atmospheric CO2.
The environmental debate belongs somewhere else.
I just want a simple “rule of thumb” for gravity points with regards to how many volumes of CO2 get produced for each gravity point.
Another way of asking the question would be: “how many gravity points does it take to produce one volume of CO2?”
I’ll have to read through my article and check that I got this right. But if you try to calculate the carbonation you can get from residual fermantables in the beer you need to work with the read extract and not the apparent extract. It just so happens that:
delta real extract = 0.82 * delta apparent extract
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 ovservation 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.
I also updated the wiki article. After doing the math and rearranging some formulas I found that what I had written there was more complicated than it has to be. I liked the “windings” reference, BTW. Though I’m trying to get better at communicating a difficult subject.
It was surprising to me that the OG does not matter even though we need to convert apparent extract (i.e. gravity) numbers to real extract numbers. So I also tested this in my carbonation calculator and it is true, you can change the OG and the carbonation doesn’t change.