Bulk Priming Definitions

Bulk priming: The addition of all the priming sugar to the beer, either into the fermenter or a separate bucket into which the beer has been racked (bottling bucket). The term contrasts with the conventional practice of adding “1 tsp. per 750 mL per bottle”.

CO₂Supersaturation: The phenomenon in which green beer contains more CO₂ in solution than it is theoretically able to. The energy produced by yeast cells is believed to be responsible for causing the excess CO₂ to dissolve, something similar to when we force salt or sugar into solution with heat. When the salt or sugar solution is cooled, the solute does not immediately come out of solution. With supersaturated beer, there will be a gradual return to simple saturation over time.

Dextrins: Long chain sugars that are not easily metabolised by yeast. There is a whole family of compounds, some are essentially impossible for yeast to metabolise, whilst others will be consumed, but at a relatively slow rate compared to the simple one and two glucose molecule sugars like glucose, sucrose, maltose and fructose.

Dextrose: also known as corn sugar. Dextrose is a simple sugar very similar to glucose. It is commonly sold under the name dextrose, but is actually dextrose monohydrate. The monohydrate simply means that each glucose molecule contains one water molecule bound to it. Therefore, more dextrose is required for priming than pure glucose or sucrose on a weight for weight basis.

Green Beer: Beer that has finished fermentation and is ready for priming.

Gyle/Speise: Sanitary unfermented wort that can be added in place of priming sugars. This is similar to kräusening but the wort is not actively fermenting. Speise generally means unfermented wort used as a source of sugar for priming. This is also covered in Part II.

Kräusening: A method of priming. Instead of adding sugar, you add actively fermenting wort to carbonate and assist the conditioning of beer. The unfermented extract in the fermenting wort replaces priming sugar. This procedure is covered in Part II of this article.

Priming: To add fermentable sugar to beer at bottling or kegging. Suspended yeast ferments the added sugar producing CO₂. In a closed vessel, the CO₂ causes an increase in pressure and dissolves in the beer, leading to carbonation.

Priming sugar: Any fermentable sugar added for priming. Priming sugar may be sucrose, dextrose, glucose, dry or liquid malt extract, or honey. (Other sources of fermentable sugar can also be used, one of which is unfermented wort. Part II of this article is devoted to this technique.)

Volumes of CO₂: This is how some people measure the CO₂ content of beer. It is not the most scientific unit of measurement, but it is commonly used, so we include it in this document for the sake of completeness. If you had a closed vessel totally full of CO₂ gas at standard temperature and pressure (STP: one atmosphere pressure; 0 °C), then dissolved all of this gas into an equivalent volume of beer at STP, you would have increased the CO₂ in the beer by one volume. In other words, one volume of CO₂ is equal to one litre of carbon dioxide dissolved in one litre of liquid at STP, two volumes is equal to two litres of gas in one litre of liquid. Although this measure of CO₂ content is easy to visualise, it is defined at STP. As beer is not always at STP, we prefer to use grams of CO₂ per litre of beer for measuring dissolved CO₂. This also complies with metric units and is consistent with the presentation of gravity in degrees Plato (g sugar per 100 mL) and priming rates in grams of sugar per litre of beer.