Lesson 3 - Beer Foam SAQ
This Lesson allows you to test yourself on the material covered in the lesson Beer Foam, and to determine the level to which you have met the learning outcomes.
Suggested Response - Q5
** Foam tests are attempting to mimic the consumer experience of beer foam. How do the two principles used in foam tests attempt to mimic this? Describe the limitations of the current methods.
Response:
Foam measurements either simulate a beer-pour or generate and measure the collapse of a foam. The former is limited by its inconsistency while foam generation methods do not mimic the actual consumer experience of beer foam. The Rudin method uses a degassed beer as its starting point.
Methods measuring beer drainage from foam such as the Sigma, Foam flashing and Rudin methods, use the limiting assumption that drained foam is unstable and collapses, however, this is not necessarily the case, for example, in Nitrogenated beers.
The generally adopted method is the Nibem foam tester, which has good reproducibility. Foam is flashed from a sample using CO2. The time it takes to collapse over 30 mm is measured by the use of conductivity probes that travel with the collapsing foam head.
Although this method suffers from the same artificial foam generation limitations as the other methods, it has proven to be a quick and reliable objective method for foam measurement globally.