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.
Determination of the "air volume" (gas volume other than carbon dioxide) in the headspace of bottles and cans
Suitable for determination in beer, mixed beer beverages and carbonated beverages
The method provides valuable information on effective and uniform foaming and undercap gassing during can filling.
The gas in the headspace of bottles and cans is captured under a funnel filled with water and subsequently migrates very slowly through a column of liquid containing potassium hydroxide or sodium hydroxide, whereupon the carbon dioxide also contained in the headspace is bound by the caustic solution. The remaining gas, consisting of nitrogen and oxygen, is captured in a burette, from which the volume can be read. The value from the burette is expressed as “air in headspace” [1].
Determination of the "air volume" (gas volume other than carbon dioxide) and oxygen in the headspace of cylinders and cans
Suitable for determination in beer, mixed beer beverages and carbonated beverages
The burette containing the caustic solution, in this case, is equipped with a short capillary outlet. A tube is attached to this outlet, connecting the burette to a second burette with a lower capillary outlet. The second burette contains an alkaline solution of sodium dithionite, which binds oxygen [1, 2]. In the first burette, the volume of air is measured, and in the second, the volume of nitrogen.