Determination of the fermentable extract in beer and wort
This method is suitable for all types of beer and wort.
Beer or wort is fully attenuated under agitation in an Erlenmeyer flask after yeast has been added. From the difference between the extract content prior to fermentation commencing (original gravity) and after fermentation is complete, the limit of attenuation is calculated.
Real extract minus apparent extract of the fully attenuated beer (from which the alcohol was removed) yields the value for “apparent attenuation”, because during the final stages of attenuation alcohol is produced.
The portion, which has actually been fermented, can be calculated through multiplication by the factor 0.81. This factor is related to the so-called attenuation quotient q [1].
Suitable for all beverages
The energy value or caloric value of beer is calculated according to Council Directive 90/496/EEC and is based upon the amount of protein, carbohydrate, alcohol, glycerin and organic acids. For performing the calculation, caloric values are attributed to 1 g of each of the following: 17 kJ (4 kcal) of protein or utilizable carbohydrate, 29 kJ (7 kcal) of ethanol, 13 kJ (3 kcal) of organic acid, and 10 kJ (2.4 kcal) of higher alcohols. (Fat is not included in the calculation for beer.)
This is a mathematical method for calculating the dextrin content as a difference between the total glucose content and the fermentable extract as determined through analytical methods.
Suitable for beer
The dextrin content is calculated through multiplication of the difference between the total glucose content and the fermentable extract by a factor of 0.915.
Suitable for beer
The carbohydrates are calculated as a sum of the fermentable extract as determined through an analytical method and through the calculated value for dextrins according to B-420.43.999 Berechnung der Dextrine.
Suitable for beer
Aside from carbohydrates composed solely of glucose molecules (with, for example, 0.69 g/100 ml of utilizable carbohydrates remaining in the beer), in highly attenuated beer there are small amounts of pentose molecules (approx. 300 mg/l) and also various glycosides (approx. 100–200 mg/l).
According to their degree of digestibility, additional utilizable carbohydrates amount to 500 mg/l at the most (equal to 0.05 g/100 ml). As a rule, 0.05 g/100 ml is also added to the total value for carbohydrates.
Suitable for beer
Aside from the total glucose content, there are other carbohydrates which can be added together to yield the sum of the bread units in a (highly attenuated) beer.