Determination of the proportional composition of grist fractions through sieve analysis
Malt grist, grist from adjuncts
The extract yield in the brewhouse is highly dependent on optimal milling of the malt or other grain. The composition of the brewery grist should therefore be monitored on a regular basis.
The sieve analysis is performed on a sample of brewery grist of a known weight with a shaking device containing a set of sieves (according to DIN ISO 3310-1 specifications or a Pfungstädter plansifter sieving device).
Volumetric determination of the husk fraction
Grist from malt or adjuncts
The sieve analysis is performed on a sample of brewery grist of a known weight with a shaking device containing a set of sieves (according to DIN ISO 3310-1 specifications or a Pfungstädter plansifter sieving device). The material retained on sieve 1 is then poured into a 500 ml graduated cylinder and the volume (without shaking) is read on the graduated cylinder.
This method describes how to classify barley according to size using a laboratory sieving machine.
Barley intended for the production of malt is to be evaluated on the basis of the characteristics described below.
A barley sample is classified into fractions according to kernel size in a sieving machine containing three sieves with defined slot widths.
Wastewater generated in the industrial production of beer and food
Well-mixed wastewater is poured into an Imhoff funnel, and the volume of sludge is recorded using the volumetric scale on the graduated cylinder after a settling time of two hours.
After decanting the supernatant, the deposits are quantitatively transferred to a platinum dish in which, after drying at 105 °C, the dry residue after evaporation is determined by weight.
After annealing in a muffle furnace at 550 °C for 30 min, the ash content is determined gravimetrically.
The annealing losses are calculated from the difference in weight between the dry residue after evaporation and the ash content.
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.
Determination of the dissolved nitrogen (N2) content using heat conductivity in carbonated and non-carbonated beverages that have been nitrogenated
This analysis is suitable for determining the concentration of dissolved nitrogen (N2) in carbonated and non-carbonated beverages that have been nitrogenated.
Dissolved nitrogen in a liquid medium is measured using the same procedure as the CO2 determination, i.e., using heat conductivity.
CO2 is employed as a purge gas in the beverage industry. Therefore, in order to measure nitrogen, the change in thermal activity and CO2 and N2 is used. The thermal conductivity is determined in a small measurement chamber, which in turn is separated from the material being measured by a semipermeable membrane. Diffusion through the membrane changes the thermal conductivity in the measurement chamber.
The gas volume in the measurement chamber is fully replaced in cycles of 10–20 s. The changes in thermal conductivity over time are a measure of the diffusion of N2 through the membrane, which allows the concentration in the medium to be calculated, taking temperature into account.
The calculation for the concentration of N2 is achieved using the change in thermal conductivity in the measurement chamber, also taking the temperature into account.
Since the thermal conductivity of oxygen is similar to that of nitrogen, a second channel may need to be used to compensate for any oxygen in the medium [1].