Hops and hop products intended for use in beer brewing or elsewhere in the food industry
The volatile constituents in hops or hop products are obtained by means of steam distillation. The hydrocarbon and oxygen fractions are separated using a process involving column chromatography.
Determination of the percentage of nitrogen that has dissolved in the wort during the Congress mash method
Suitable for (Congress) mash
The Kolbach index is used to express the quantity of the nitrogenous substances found in malt, which go into solution under the conditions present during the Congress mash method. It is a measure of the degree of proteolytic modification of the malt and also provides an indication for the quantity of proteolytic enzymes contained in the malt. The Kolbach index is less conclusive than other methods due to its dependence on the total nitrogen content and the provenance of the barley. Therefore, it must always be considered together with the total nitrogen content.
Applicable for all (laboratory) worts
The Congress wort is heated in order to inactivate the amylolytic enzymes, and afterwards, yeast is added and the wort is allowed to completely ferment out at a minimum temperature of 20 °C in a fermentation tube (fig. 1). The difference in the extract before and after fermentation is measured in order to calculate the limit of attenuation.
Applicable for all (laboratory) wort
The Congress wort is heated in order to inactivate the amylolytic enzymes, and afterwards added to an Erlenmeyer flask along with 7.5 g/100 ml yeast where it is allowed to completely ferment out under constant agitation. The difference in the extract before and after fermentation is measured in order to calculate the limit of attenuation.
Applicable for all (laboratory) worts
The Congress wort is heated in order to inactivate the amylolytic enzymes. Afterwards, 16 g/100 ml yeast is added, and the wort is allowed to completely ferment out in approx. 7 h.
wort, beer
Yeast (16 g/100 ml) is added to (boiled) wort or beer in an Erlenmeyer flask and allowed to ferment completely in approx. 7 h under constant agitation. The limit of attenuation is calculated from the difference between the extract content prior to (original gravity) and after fermentation. [1, 2, 3]