This method describes how to determine the moisture content of specialty malt.
Specialty malt intended for use in beer brewing or elsewhere in the food industry
This method describes how to determine the extract content of roasted and caramel (crystal) malt by means of a modified Congress mash method.
Roasted and caramel (crystal) malts intended for use in beer brewing or elsewhere in the food industry
Pilsner malt, of which the moisture content, extract and color are known, is mashed together with roasted or caramel (crystal) malt according to the Congress mash method. The extract content of the roasted or caramel (crystal) malt is determined by taking the analysis values for the pilsner malt into account.
Prediction of the extract content and predetermination of the processability and value of a lot of barley for brewing purposes
The behavior of barley during the malting process, which is intended for large-scale malt production, must be known.
MEBAK approved and adopted a micromalting procedure on 6 April 1971 as a standard method for predicting the extract content and for determining the suitability of barley varieties for malting. In 2003, MEBAK shortened the procedure by one day for a total of six days for vegetative growth (steeping and germination), the same length of time as the EBC procedure.
Malt intended for use in beer brewing or elsewhere in the food industry.
The malt is placed in a stainless steel wire sieve drum. For a designated time period, the kernels are pressed against the rotating wire sieve drum by a roller, whereby the friable portion of the malt falls through the sieve, while the glassy portion is retained in the drum.
The compounds in the malt dissolved in the mash liquor during a standardized mashing process using finely ground malt (fine grist) are determined in this analysis.
Malt intended for use in beer brewing or elsewhere in the food industry
The Congress mash method primarily serves to determine the extract content of malt.
The extract content is determined by the weight ratio sL 20/20 of the wort on the basis of the official sugar tables (Plato tables) at 20 °C. sL 20/20 stands for the weight ratio of a volume of wort at 20 °C to the same volume of water at the same temperature.
Furthermore, the following is tested over the course of this analysis: Iodine test (saccharification time), odor of the mash, wort run-off, clarity of the filtered wort; the Congress wort is also used as a basis for a wide variety of further analyses.
Determination of maltose and maltotriose by enzymatic means
Suitable for wort, beer, malt beverages, nutrient beer, mixed beer beverages, NAB, juices and beverages.
Maltose is the main component of beer wort or wort extract.
Maltose and sucrose are cleaved by the enzyme α-glucosidase (maltase) at pH 6.6 into two molecules of D-glucose and D-fructose, respectively:
\(\text{Maltose}+H_2O \hspace{0.8em} \xrightarrow{α–glucosidase} \hspace{0.8em} {2 \hspace{0.2em} \text{D–glucose}}\)
\(\text{Sucrose}+H_2O \hspace{0.8em} \xrightarrow{α–glucosidase} \hspace{0.8em} {\text{D–glucose}+\text{D–fructose}}\)
The D-glucose formed is phosphorylated by the enzyme hexokinase (HK) and adenosine 5'-triphosphate (ATP) to glucose 6-phosphate (G-6-P):
\(\text{Glucose}+\text{ATP} \hspace{0.8em} \xrightarrow{HK} \hspace{0.8em} \text{G-6-P} \hspace{0.2em} + \hspace{0.2em} \text{ADP}\)
In the presence of the enzyme glucose-6-phosphate dehydrogenase (G6P-DH), G-6-P is oxidized from nicotinamide adenine dinucleotide phosphate (NADP) to gluconate-6-phosphate. Reduced nicotinamide adenine dinucleotide phosphate (NADPH) is formed:
\(\text{G-6-P} \hspace{0.2em} + \hspace{0.2em} \text{NADP}^+ \hspace{0.8em} \xrightarrow{G6P-DH} \hspace{0.8em} \text{gluconate-6-phosphate} \hspace{0.2em} + \hspace{0.2em} \text{NADP}^+ \hspace{0.2em} + \hspace{0.2em} \text{H}^+\)
The amount of NADPH formed during the reaction is equivalent to the amount of glucose. NADPH is measurand and is determined based on its absorbance at 334, 340 or 365 nm.
The enzyme α-glucosidase is group specific, i.e., the specificity is directed to the type of glycosidic bond.
Only α-1,4 bonds, i.e., in addition to maltose, sucrose and maltotriose, but not maltotetraose, are cleaved under the given conditions. Therefore, the sucrose content must be taken into account in the maltose calculation (the maltose approach records the glucose formed from maltose and sucrose and the free glucose, the sucrose approach records the glucose formed from sucrose and the free glucose).