A Guide To Carbonation

Something that I think that is often overlooked when it comes to packaging or bottling beer is the carbonation (or the level of fizz).

The level of carbonation can contribute to the beer in a variety of ways. It affects the level of perceived body in the beer and the mouthfeel, the formation of a foamy head and also enhances the flavour compounds present in the beer. Anyone who has ever drunk a flat beer will know it’s no way near the same as a correctly carbonated beer.

There are a couple of ways to achieve carbonation for home brewers. If you are kegging your beer you can force carbonation by pressurizing the keg with carbon dioxide, you can follow the technique of krausening which involves adding unfermented wort to fermented beer although this is not entirely practical for home brewers and finally you can bottle condition which involves adding priming sugar to the fermented wort then bottling which allows the fermentation of that sugar to be carried out in the bottle. The CO2 naturally created as a byproduct of fermentation has nowhere to go in a sealed bottle so is dissolved into the beer.

So How Much Priming Sugar is Enough

Below is a table showing how much sugar is required in a 19 litre batch of home brew. As you can see on the table to achieve a low level of carbonation in a 19 litre batch you would need 75 grams of table sugar added to the fermented beer. The easiest way to do this is to create a solution by adding the sugar to a small amount of water and boiling it to sterilise it and ensure the sugar is fully dissolved. This can then be cooled and added to the bottling vessel and the beer racked on top of it.

	Very Low	Medium	Very High
Grams of Corn Sugar in 19 Litre Batch	75	115	150
Volumes of CO2	1.9	2.4 – 2.5	2.9

 

The table also shows “Volumes of CO2”. This term Volumes of CO2 is a way of measuring the level of carbonation in your home brew, it means for 1 volume of CO2 1 litre of carbon dioxide is dissolved into 1 litre of liquid or beer.

So we can see for the chart above we can see for the high levels of carbonation 2.9 litres of CO2 has been dissolved into every 2.9 litres of beer. It is good to know this measurement when brewing different styles of beer. Below is another table (I know another one) which I hope will be useful to you if you are brewing a particular style of beer.

Now to work out how much table sugar is needed your best bet is to use a calculator. There is a variety of software that can do these calculations or you can try an on line calculator such as this one at Brewer’s Friend.