• Welcome to the new forum! We upgraded our forum software with a host of new boards, capabilities and features. It is also more secure.
    Jump in and join the conversation! You can learn more about the upgrade and new features here.

calculating priming sugar / SG

fabiosmania

Apprentice
Joined
Dec 11, 2013
Messages
3
Reaction score
0
When I change the volume of CO2 (adding more sugar in the prmming) the SG in the beersmith dosen't change. Someone know's why?
 
In normal conditions, priming sugar is 100% fermentable and adds a negligible amount of alcohol (usually under 1/2% abv.). It only increases gravity by 1.002, but the effect when the beer is carbonated is nil.

If you want to use enough sugar to add alcohol, it should be added to the recipe ingredients used in the boil or fermenter.
 
but in my recipe when I add 300g of cane sugar the SG is 1.048 and the abv 5%.. when I don't they are 1.046 and 4,6%..

and the beersmith indicate's 304g of table sugar to the priming.

so, adding the priming it will or not change the abv/SG? For me it should increase like in the fermentation step, but maybe it's just intuition..

thank you
 
Exactly! You're intuition is correct. That is the 1.002 gravity difference.

The 0.4% difference is negligible for most brewers. In a very light session beer that you're describing it has a bit more meaning and influence. In the US, any beverage under 0.5% is considered non-alcoholic. That was my reference point in saying "negligible."

The other reason it's not accounted for in BeerSmith is that priming sugar is added after the brewer has made their "final gravity" measurements. In fact, I don't think there are very many recipes (if any) that consider it when stating the potential alcohol. So, it isn't just BeerSmith, it'd be any brewing software or standard brewing technique to ignore the alcohol contribution of priming sugar.

I guess it is meaningful to commercial brewers who are taxed on alcohol content. If that's your case, then it just has to be a part of your procedure to add it as a matter of course.
 
Just to illustrate how adding cane sugar to the boil affects ABV, I added 1/2 lb (8 oz) to a recent batch of pale ale that was rated at 5.6% ABV.  After plugging all the data into BS, the estimated ABV is now 6.3%.  When I bottle next week, it will get the standard 5 oz. of priming in the bottle bucket, but that won't affect the ABV any, if at all.
 
Back
Top