This method describes how to determine the electrical conductivity of water using a conductivity meter.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The electrical conductivity of a water sample is regarded as a sum parameter of all of the ions dissolved in the water sample. The electrical conductivity is determined by the ion concentration and the types of ions as well as the temperature and the viscosity of the solution. Due to dissociation of the water molecules themselves, water containing no dissolved extraneous ions possesses an extremely low electrical conductivity of ≤1 µS/cm-1. Drinking water often exhibits conductivity between 100 and 1000 µS/cm-1 (limit threshold according to the Trinkwasserverordnung – TrinkwV (the regulations governing drinking water in Germany): 2500 µS/cm-1 at 25 °C). By comparison, rainwater exhibits a value for electrical conductivity between 30 and 60 µS/cm-1, while that of sea water is commonly 42,000 µS/cm-1.
Determination of the concentration of dissolved carbon dioxide in carbonated beverages in tanks, lines, bottles and cans by means of thermal conductivity
This analysis is suitable for dissolved carbon dioxide in carbonated beverages in concentrations ranging from 0–6.9 g/l.
The thermal conductivity is measured in a small chamber, which is in turn separated using a semi-permeable membrane from the medium being measured. The diffusion through the membrane alters the thermal conductivity in the measurement chamber. The gas volume in the measurement chamber is completely replaced in 10–20 s cycles. The changes in the thermal conductivity over time are a function of the quantity of CO2 diffusing across the membrane. Using this value and taking into account the temperature, the concentration in the medium being measured can be calculated. Other dissolved gases, such as nitrogen and oxygen, do not affect the result of the measurement, since either nitrogen or air is used to replace the gas in the measurement chamber [1].
Prior to storage, the moisture content of barley must be determined.
Measurement of the electrical resistance in the ground and pressed sample
This method describes how to determine the extract content of malt used to produce laboratory wort.
Malt intended for use in beer brewing or elsewhere in the food industry
The extract content of malt refers to the compounds from finely ground malt (fine grind), which are brought into solution during a standardized mashing process.
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.
This method describes how to determine the time required for filtration of laboratory mashes.
Malt intended for use in beer brewing or elsewhere in the food industry
The time from the beginning to the end of filtration is determined when producing a laboratory mash.
This method describes the fluorimetric determination of high-molecular weight β-glucans in laboratory worts.
Suitable for all types of (laboratory) worts
The fluorochrome Calcofluor forms a complex with high molecular weight β-glucans (molecular weight greater than 5 kDa). Complex formation results in an increase in fluorescence; however, this fluorescence is extremely unstable due to photochemical degradation.
Reproducible measurements for fluorescence and determination of β-glucan are possible through measurement in an automatic analysis system based on flow injection (flow-injection analysis). The apparatus is calibrated using purified barley β-glucan standard solutions.