The STTP priming sugar calculator simplifies the process of calculating the recommended amount of several common priming sugars for over 90 different beer styles. Simply select your beer style, batch volume, fermenting temperature and the calculator will give you the average reccomended amount of priming sugars needed for your beer style.
Priming Sugar Formula
The below priming sugar formula, is a simplified version of the original formula that was published in the Zymurgy article, ‘Brew By The Numbers’.
PS: Priming Sugar weight in Grams.
Vbeer: Volume of your Beer in Gallons.
VCO2: Desired Co2 volume for your beer.
Tferm: Temperature of Your Beer prior to bottling it. (Fahrenheit)
PS = 15.195 × Vbeer × (VCO2 – 3.0378 + (0.050062 × Tferm) – (0.00026555 × (Tferm)2))
So now all we need to do is plugin our known variables for Beer Volume, Temperature & Desired C02 level. For this example we will use a 5 gallon batch of beer @ 65 degrees Fahrenheit and a target C02 level of 2.5.
**Remember your order of operations!
PS = 15.195 * 5 gallons * (2.5 -3.0378 + ( .050062 * 65) – ( .00026555 * 65^2))
PS = 75.975 * (-0.5378 + 3.25403 – 1.12194875)
PS = 121.13 grams (corn sugar)
Priming Sugar Conversion Formula
While the above formula is fairly straight forward, it was written to calculate the priming sugar weight for sugars & adjuncts that have a 100% yield rating. We use the below formula to translate the known values for our corn sugar priming calculations to find the unknown weight of alternative priming sugars.
In the example below, We will be converting our known numbers of corn sugar to use honey instead.
4oz of Corn Sugar * 42 ppg * 100% yield = ? oz of honey * 38 ppg * 95% yield
The PPG values listed above are simply the parts per gallon rating for Corn Sugar & Honey (respectively). The PPG rating can be found by looking up the sugar/adjunct’s potential rating, usually written as 1.0xx.
1.042 potential = 42 PPG
1.038 potential = 38 PPG
The yield value on the other hand is a bit more difficult to find. The BeerSmith ingredients section is a great resource for finding an ingredients yield. If you don’t have access to BeerSmith, You can checkout the resources section at the end of this guide for additional resources for finding your yield %.
Once you know your ingredients PPG value and yield percent. We can now solve for the required weight of Honey needed to prime our beer.
(4 oz)(42)(100%) = (X)(38)(95%)
First let’s solve for Corn Sugar.
4*42*1.00 = 168
Now We need to solve for X.
168/38/.95 = 4.6537 ounces of Honey.
Disclaimer: Over carbonating your beer can lead to swollen caps, excessively foamy beer and in extreme cases your bottles may even explode. If are you are still unsure of your volume of priming sugar after using this calculator, error on the side of caution and target a lower carbonation volume. You can always adjust as needed in future batches if your carbonation is too low.