Beer Quality: Foam

In this module, we’ll introduce you the overall idea of beer quality, focusing specifically on the foam of beer. We'll discuss how foam appearance impacts someone’s perception of a beer’s flavor and overall quality. We’ll also take a look at what the research tells us about beer foam preferences from various countries around the world. We'll discuss the physical parameters that impact foam and methods for producing more bubbles. We'll also discuss the physics of bubbles and factors that affect their size and stability.

In this module, we'll begin by talking about foam positive and foam negative materials, and the various chemical species that influence foam stability. We will discuss the affect that hydrophilic (water loving) and hydrophobic (water hating) chemicals have on the stability of foam. We also review some of the research that has been done in this area to give you a more nuanced view of this subject. We will also look at the results of various research projects that compare the foaming properties of albumins and hordeins. Also in this module, we'll review methods and tools available for measuring the stability of foam and for measuring foam lacing. Finally, Joseph Williams will walk you through a number of foam measuring techniques at the UC Davis brewing and food science laboratory.

In this module, we'll discuss how the raw materials chosen for brewing can affect foam. We will discuss various factors of beer production that affect foam including sweet wort production, boiling, and hops and hop products. We'll also discuss the impacts that yeast, filtration, stabilization, packaging, and dispensing have on foam. We'll discuss common foam problems that occur during the dispensing and serving of beer, including proper glass cleanliness. We also discuss ways of testing for foam positive and negative materials in the beer. We'll discuss common reasons foam positives are lacking in beer and reasons foam negative materials are present in beer.