Priming calculators all say different things

[autonomist3k]

I've plugged the same info into several different priming sugar calculators and they all say different things.

Palmer's book says 4.2 oz
brewheads.com says 5.04 oz
Northern brewer says 4.77 oz
Brewers friend says 5.2 oz
beersmith says 4.73 oz

Why do they all differ so much?
Shouldn't they use the same math formulas?
Is there one that is more trustworthy than the others??

I've had pretty inconsistent carbonation with most of my brews so this is kinda frustrating to me.

 

[Calder]

In theory they should all be the same. I use beersmith myself.

Did you use the same temp and sugar type in each one.

 

[divrguy]

I use tastybrew.com
Since most of the IPA kits come with 4oz corn sugar and using table sugar and the same volume of co2 it come in about .2 less, I would say use palmers.

Tastybrew puts me right where I need it without fail.

 

[brewkinger]

One of the factors in this calculation is the temperature of fermentation, which determines an amount of residual CO2 that is found already in the beer.
A safe rule of thumb is 3/4 to 1 ounce of corn sugar per gallon of beer.

 

[pumpkinman2012]

+1 on using Beersmith, much easier since the update.

 

[divrguy]

+1 to Beersmith too. I always look at the mobile app and it doesn't show table sugar just corn sugar so I forget it has it.

 

[jakeasaur]

One of the factors in this calculation is the temperature of fermentation, which determines an amount of residual CO2 that is found already in the beer.
A safe rule of thumb is 3/4 to 1 ounce of corn sugar per gallon of beer.

^ I always use 3/4 oz per gallon. Never had an issue. On a side note I can't stand over carbonated beer so I always go on the lighter side with the corn sugar

 

[autonomist3k]

I think I'm going to use beersmith for now on since it seems to be in the middle of the range that the calculators are giving me.

 

[JuGordon]

^ I always use 3/4 oz per gallon. Never had an issue. On a side note I can't stand over carbonated beer so I always go on the lighter side with the corn sugar

I hate over carbonated beer as well. I, however, use Northern Brewers calculations and have had perfectly carbonated beer since. Everything from my ESB to Imperial IPA have all turned out perfectly carbonated to style.

 

[fartinmartin]

Those that you list show about 20% variation! I would just use the same one all the time then adjust according to experience.
I use .8oz/gal on most of my brews, most of the time it is less than many sources suggest, but .8oz/gal does it for me .

 

[autonomist3k]

I'm not sure if this is related, but I'm starting to drink an amber that I brewed, primed with 5 oz, beer was 60* at bottling, kept at 70* for 3 weeks, and for some reason seems way under carbd.
The only thing I can think of is that the 2 cups of priming solution was still pretty warm(if not hot) when I racked the beer onto it in the bottling bucket. could it have hurt the yeast? there's still some carbonation, just not a lot, and it seems to me that I used a lot of sugar for what I wanted.

I swirled every bottle tonight and will check again in a week, but this batch is confusing the hell out of me lol.

 

[JuGordon]

How long did it carb for?

 

[autonomist3k]

3 weeks

 

[JuGordon]

Well then, time definitely didn't play a factor...

 

[T29]

+beer smith is good

 

[ayoungrad]

My thoughts:

1. Always weigh priming sugar. Volume depends on too many variables and is therefore completely inaccurate.

2. All sugars are not equal. There are adjustments for cane, corn, honey, etc which must be kept in mind for desired final carbonation.

3. The highest temperature at or after the completion of fermentation should be utilized in the determination of the amount of priming sugar. This determines the residual CO2. Residual CO2 is dependent on temperature - more CO2 is dissolved in liquid at a lower temperature. And the residual CO2 determines how much more CO2 you need for a desired level of final carbonation.

4. Different styles warrant different final levels of carbonation. If the calculator you use does not ask for the desired level of carbonation, then it is not a calculator you should use.

5. I used to use: http://hbd.org/cgi-bin/recipator/recipator/carbonation.html. It gels well with Palmer calculations as well as several scientific formulas out there.

Also bear in mind that depending on the conditions of carbonation (time to carbonate, temperature during carbonation, time in primary and secondary, etc... i.e. yeast health) it may take much more or much less time for the bottles to reach final/stable carbonation levels.