Ice cream - Making ice-cream

11 important questions on Ice cream - Making ice-cream

What are the 4 different steps to produce a good ice cream?

  1. Mix preparation
  2. Ageing
  3. Freezing
  4. Hardening

Why is hardening of ice cream necessary?

Scraping during freezing only has a temperature of -5C.

Mention 2 techniques for ice cream making.

  1. Low temperature extrusion (-15 C), no need for hardening
  2. Liquid nitrogen (-196 C), large difference in temperature,  very fast, very small crystals
  • Higher grades + faster learning
  • Never study anything twice
  • 100% sure, 100% understanding
Discover Study Smart

Why are the liquid ingredients of ice cream not heated higher than 65C?

Because proteins could denature at a higher temperature.

What happens during the freezing step?

The mix is aerated and frozen to generate ice crystals, the air bubbles, and the matrix.

How do the ice crystals grow during hardening?

  1. Propagation
  2. Recrystallization (Ostwald ripening and accretion)

What is the difference between propagation and recrystallisation of ice crystals?

Propagation: The size of all ice crystals is increased as more water freezes.
Recrystallisation: It leads to a larger average ice crystal size but not an increase in the total amount of ice.

How can the degree of recrystallization be decreased?

The freezing process should be as rapid as possible.

How is the ice phase volume determined in water ices?

By the temperature of the outlet.

What are characteristics of the ice cream in low temperature extrusion?

  • Higher shear stress applied
  • Smaller air bubbles and ice crystals (finer microstructure)
  • Low temperature when leaving extruder --> less coarsening of ice crystals and air bubbles
  • High shear stress --> Increases partial coalescence of the fat

When is liquid nitrogen used for ice cream?

When the freezing point of fruit ice is very low, the temperature of the ice maker will not be low enough to create ice crystals. Nitrogen is very cold, nucleation is very rapid, and therefore a lot of tiny stable ice crystals are formed.

The question on the page originate from the summary of the following study material:

  • A unique study and practice tool
  • Never study anything twice again
  • Get the grades you hope for
  • 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
Trustpilot Logo