What is priming?
Priming is the practice of adding a small amount of fermentable material (i.e. sugar) to beer just before bottling so as to provide enough CO2 or carbonation to make the beer bubble and froth. There is a lot of information and complex tables on carbonation levels based on pressure and temperature. Don’t worry about these as they are only really important when you start kegging and using forced carbonation.
What is bulk priming?
Bulk priming is when the sugar is in solution and mixed with the entire batch at once immediately prior to bottling as opposed to adding the sugar to each bottle.
Why bulk prime?
It is quick and easy and, if done properly, it provides a more consistent level of carbonation. It is also independent of bottle size.
How do I do it?
There are two basic ways, straight addition and racking. Straight addition is where you add the sugar solution directly to the beer and mix it in. Racking is where you put the sugar solution in a separate vessel and ‘rack’ or transfer the beer to the other vessel, mixing it as it goes.
How do I make the sugar solution?
First you need to decide what style of beer you want and how well carbonated. If you think of European lager as ten (think of Heineken poured from the tap where they push the head off with a stick) which is about 4 volumes of CO2/litre STP and dead flat beer as zero, English bitter is about three to five (1.5 V/l CO2 STP) and Australian style beer about nine. You need to decide what you want to prime with. The normal choice is dextrose or malt extract but you can use any type of sugar such as white, brown, raw, even golden syrup. You can use honey, maple syrup or anything else that ferments with beer yeast. You also need to know how much beer you have to bottle.
The attached table will tell you how much sugar is required but a rule of thumb is 180g of white sugar for a 23l batch for reasonably high carbonation.
Mix the sugar with about 1.5ml for every gram of sugar, less if the sugar is already syrup, in a clean, detergent free saucepan and bring it to the boil or until the sugar is dissolved. With unpasteurized honey, keep it over 80 deg for a few minutes. Let it cool in the pan with the lid on. When it is below about 50 deg you are ready to mix it in.
How do I do Straight Addition?
For straight addition you need to sanitize a large stirring spoon. Remove the lid from the fermenter. Gently pour the solution in as you gently stir the beer. Avoid stirring up the trub or splashing. A small amount of oxygen will be consumed by the yeast but excess will affect the flavour. When stirred in, wait 20 min and bottle as normal.
Why or why not do straight addition?
You do not need an extra vessel and there is less risk of an infection or oxidization as you do not rack. However, you do risk getting cloudy beer and excessive yeast in the bottles.
Racking reduces the risk of stirring up the spent yeast and hops in the trub. You will get less yeast in the bottles but still have enough to carbonate.
How do I rack to bulk prime?
You will need a primary or secondary fermenter full of beer ready to bottle. You also need another vessel the same size or larger that you can bottle from such as a spare primary fermenter or a cube storage container with a tap on it. You will need about 2m of 12mm diameter plastic hose that fits snugly in the taps. Cleanliness is important and all gear should be sanitised but as the beer has fermented and has alcohol in it there is a much lower risk of infection than with fresh wort. If you have a spare yeast reduction device, fit it to the tap of the empty vessel with the slot facing sideways. This will swirl the beer and mix it as it enters the vessel. Place the full vessel on a bench or table and the other on the floor near by. Use the hose to connect the two taps. Pour the sugar solution into the empty vessel on the floor. Open both taps and the beer will flow from one vessel to the other. When the top vessel is almost empty observe the beer and tilt the vessel to get as much beer as you can without getting to much trub. Turn off the bottom tap first, then the top tap (order is not important). Lift the bottom vessel on to the bench. Carefully remove the hose from the top tap and the bottom tap to avoid spilling beer. Immediately bottle as you normally do. You will have very little waste at the bottom of the vessel.