Five Foam Factors, Revisited
At the start of this chapter we talked about Professor Abbots Five Foam Factors that were conducive to great foam for latte art. First, we wanted foam that was wet, with a relatively low aeration percentage. The sweet spot for Barista Hustle was around a 33% aeration level. Less than 20% aeration is too wet for latte art purposes, and foam above a 50% aeration level is too dry.
Second, we wanted fine bubbles with a small diameter. The whey protein found in milk contains β-lactoglobulin,