Similar to Hot Water Test, but using coffee at 85ºC. Like SDP, and the Hot
Water Test, the result is determined by the degree of agglomeration, but for
the coffee test also the pasteurization of the milk prior to the evaporation
(80-85ºC in 15 sec. with WPNI ≈ 3 mg/g), the content of Ca++ and total protein
content is important.
With high content of proteins in the milk (Jersey cows or milk from low
season) it is difficult to produce powders with a good coffee test, which
should be <0.4 ml. Standardizing the milk with lactose or permeate to adjust
the protein content is used in the industry. Concentrate preheating to 80ºC
and/or addition of phosphates and/or citrates to precipitate the ionic Ca can
be used as well.