Saturday, January 15, 2011

Bottle Priming Calculator

[Originally posted on August 2010] After searching around the Internet I was able to locate a few formulas for calculating the amounts of priming sugar needed to produce the right amount of carbonation for every beer style. The calculator is located on the Brewing Tools and Formulas page of the Screwy Brewer website. 

 Bottle Priming Calculator

 It's completely free and available for all to use and enjoy and also has a beer style carbonation guide to help you get started.


 Beer Carbonation Guide By Style

How To Use It.

 Fermenting beer produces Co2 bubbles during the fermentation process and the Co2 inside those bubbles is then absorbed into the surrounding beer as the bubbles rise to the top of the fermenter. This absorbed Co2 is known as residual Co2 or the amount of Co2 already present in the fermenting beer. The temperature of the fermenting beer determines how much Co2 can be absorbed into the beer as colder beer can absorb more Co2 than warmer beer.

I enter in the temperature of the beer itself at the time of bottling, regardless of what temperature the beer was fermented at or will be carbonated at. I do this intuitively by taking a few things into consideration one that up until bottling, the beer in the fermenter is not under pressure and is able to vent any excess Co2 into the atmosphere as the temperature goes up and that colder beer can absorb more Co2 than warmer beer.

Once the beer is bottled and tightly capped the Co2 inside the bottle at colder temperatures gets absorbed into the beer since colder beer is capable of holding more Co2. At warmer temperatures the Co2 escapes the beer and goes into the headspace inside the bottle, the area between the surface of the beer and the bottle top, as warmer beer holds less Co2 than colder beer.


I've been using the calculator this way for months now and it has given me what I consider to be the correct amounts of carbonation for all my recipes, from pale ale and stouts to wheat beers and lagers.

Example 1 (Ales):

This is an example for priming an Ale that was fermented at a constant 65F temperature until the fermentation was completed. The fermenter was then moved to a warmer 70F location for bottling the beer into 1 liter plastic PET bottles. The beer temperature rose during this time to 70F so we acknowledge that the warmer beer now contains slightly less Co2 than it did when it was at 65F.

1 liter of 70F beer at bottling contains .83 volumes of residual Co2 right out of the fermenter. If your target volume is 2.5 Co2 volumes you'll need to add 1.53 teaspoons of cane sugar to hit 2.5 Co2 volumes after the bottle has been capped and carbonation has completed.

Example 2 (Lagers):

This is an example for priming a Lager that was fermented at a constant 54F temperature until the primary fermentation was completed. The beer was then racked to a secondary fermenter and moved to a colder 34F location for lagering before bottling the beer into 1 liter plastic PET bottles. The beer temperature at bottling rose to 40F so we acknowledge that the warmer beer now contains slightly less Co2 than it did when it was at 34F.

1 liter of 40F beer at bottling contains 1.46 volumes of residual Co2 right out of the fermenter. If your target volume is 2.5 Co2 volumes you'll only need to add .955 teaspoons of cane sugar to hit 2.5 Co2 volumes after the bottle has been capped and carbonation has completed.


Serving Temperature:

In the previous example we calculated the amount of priming sugar to add to an Ale based on the difference between the residual Co2 volumes it contained at 70F and a target of 2.5 Co2 volumes. We let the bottles carbonate at 70F for a few weeks until the plastic bottles are really firm when squeezed. Now the bottles can go into the fridge to chill them down to a 40F serving temperature. When the bottle cap is removed we can hear the familiar sound of the initial rush of Co2 leaving the bottle and as the beer warms even more Co2 will escape the beer.


5 comments:

  1. I just recently bottled some beer in a couple of old wine bottles with the hinged swing top lids and, glass of course. i was wondering if there is any set amount of time limit set for carbonation to happen. its easy to tell in the plastic bottles, when they are rock hard. but how can i tell when its done in the glass bottles?

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  2. Some brewers fill a plastic 'sample' bottle with beer along with their glass bottles. When the plastic sample bottle gets really firm, usually about 2-3 weeks for me, the glass bottles should be well carbed as well.

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  3. I like your idea of a plastic sample bottle. I'll have to try that.

    I wondered about using the Mr. Beer booster as priming sugar. (I hate to waste.) From everything I have read and looking at QBrew's numbers, it looks like I can expect around the same behavior as 75% AA DME. What do you think about that?

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  4. Yes Mr. Beer Booster contains both fermentable (corn sugar) and non-fermentable (maltodextrins) in each package, so we'd expect to see roughly the same attenuation as using DME, although I have never used either for bottle priming.

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    ReplyDelete