Determination of the foam stability
Beer and beer-based beverages
In an Lg foam tester, the foam stability is determined by measuring the time it takes for the foam to collapse in a glass cylinder.
The foam is produced by pressing a constant beer volume through a nozzle (Ø 0.6 mm). The precise metering of a predetermined quantity of beer is achieved by time-controlled operation of the valve in conjunction with pressurizing the sample bottle to 2.5 bar (± 5 mbar). As the foam collapses, the height is measured optically in the glass cylinder [1].
Determination of the foam stability
Beer and beer-based beverages
In determining the foam stability with the Steinfurth Foamtester SFT, the time required for the foam to collapse in a graduated cylinder is measured.
The pressurization is carried out in such a way that the container does not require degassing. The attempered beer is injected into the measuring cylinder through a nozzle, and in the process, foam is formed. The foam stability is determined by several optical sensors detecting the time necessary for the beer/foam interface to pass by them. The precise metering of a predetermined quantity of beer, the entire process of executing the analysis and displaying the results as well as cleaning and conditioning of the measurement cylinder are performed automatically.
Determination of the capacity for foam to cling to the side of a glass
Beer and beer-based beverages
The measurement with the NIBEM Cling Meter (fig. 1) is normally performed immediately after the NIBEM foam stability measurement and serves to provide additional information on foam quality.
After the preset timer has expired, a scan head is introduced into the Haffmans standard glass while the glass is rotated slowly at a fixed level, in order to ensure that the foam has collapsed a minimum of 48 mm. An LED on the back of the scan head emits light. The diffused light, which reflects off of the inside of the glass, is read by a sensor and recorded.