Why Does ice Make Dairy Drink Thicker?

Most recent answer: 10/04/2015

Why does adding ice to a powder dairy drink, mixed with water & milk, make the drink thicker?
- Ivan Ostfeld (age 66)

My bet would be on the change in the viscosity parameter, associated with the chilling the ice provides to your drink as it slowly melts. Viscosity in general is highly temperature dependent. Theoretical understanding of complex mixtures like milk is not easy to derive, as it contains variety of proteins and saturated and unsaturated lipids. However, a study suggests that there is an emprical relationship (A. S. Bakshi and D. E. Smith, 1984):

ln(η) = 2721.5/(T+273.15) + 0.1*F - 15.8

η is viscosity in s.Pa, T is temperature in °C and F is the fat content of the dairy product in %. Here is a plot that showing a steep increase in viscosity as temperature is reduced, assuming 3% fat  content milk.



(published on 10/04/2015)