Questions & Answers
from "On Ice Cream" featured in Dairy Foods magazine
and sourced from "On Ice Cream" technical short courses.

Mix Aging:

Question: What will happens if ice cream mix is frozen before it has been properly "aged"?

Answer: The consequences of premature freezing include diminished air cell strength (with negative implications regarding shrinkage, mouthful, and shape retention on melting), and structural weakness in the product at freezer exit and after hardening. Rationale for "aging" lies in the need to properly condition the fat system so that it will function properly and consistently during the freezing process. This functionality involves fat destabilization (i.e., clumping), in which the shear in the freezer causes the fat globules to agglomerate. The agglomerated fat structures provide air cell strength and add to the body and mouthful to the product through the development of a semi-continuous structure. For fat to agglomerate properly and consistently, crystallization of the fat must be complete. Soft fat particles will not agglomerate normally. Crystallization requires removal of heat and occurs during the cold "aging" of mix. Also, the surface of the fat droplets must be conditioned so that the target degree of clumping will occur. Generally, about two hours "aging" is sufficient to reach an equilibrium crystal structure and for fat surface conditioning to be complete. When saturated monoglyceride emulsifiers are used, up to four hours may be needed. Polysorbate emulsification achieves surface equilibrium quickly, sometimes as soon as the mix is cooled.