How Much Priming Sugar?

Recently, I was asked by a fellow brewer how much priming sugar to add to a batch of beer to carbonate it. Priming sugar is something that most of us take for granted. Most kits come with a pre-measured amount of priming sugar. And those of us that prime the typical 5 gallon batch have a regular volume or weight that we use. But what happens when the batch is 4.5 gal or 2.75 gal - what then?

A typical 5 gal batch for me gets 4 ounces of priming sugar (corn sugar). I used to use 5 ounces but noticed that I usually had over carbonated beer that resembled a "gusher bug". If I want to have a beer on the well carbonated side to make it particularly effervescent then I'll do 4.5 oz per 5 gal. But recently I bottled 4.5 gals but I wanted it to be at the same carbonation level as my other batches.

So here's how I went about calculating the right amount of priming sugar to add:



Priming sugar in grams per quart:
Assumptions:
batch size = 5 gal (20 qts)
amount of priming sugar added = 4.0 oz
1 oz = 28.4 g
=> 4 * 28.4 g = 113.6 g priming sugar for 5 gal

So....

113.6 g / 20 qts = 5.68 g/qt



For 4.5 gal (18qts)......
5.68 g * 18 qts = 102.24 g priming sugar to carbonate 4.5 gal of beer with a medium amount of carbonation



I would boil 6-8 oz of water then add your priming sugar. Stir until dissolved. Continue to stir for another 30 secs. Pour it into your bottling bucket. Let it cool for a few minutes then rack your beer onto it. once you have finished racking, give the beer a gentle stirring for 1 min. Fill up your bottles and cap. Place them in an area that is the same temperature at which they were fermented. In 10 -14 days place a bottle in the fridge for a few hours, then pull it out and pry off the top and listen for that "pfssst!" sound to check the carbonation level.

Cheers y'all!