Freezing Methods

There are different type freezing systems as there is no one-satisfy- all system available. Several freezing methods available nowadays are:

1. Contact plate freezing

• Product are sandwiched between metal plates
• Regular shaped products are preferable

The video below shows the application of contact plate freezing in food industry.

2. Immersion freezing

• Cooled high-concentration solution is used
• Solutes used must safe to food
• Heat transfer is quick and high concentration solution remain liquid at very low temperature

The soda pop is immersed into a cold brine solution (-35 °C) mixed with calcium as shown in video below.

3. Freezing by contact with cooled gas

3.1. Cabinet freezing

• Cold air is distributed into a cabinet

• High heat transfer an air velocity of at least 5 ms^-1

3.2. Air blast freezing

• Cold air is blown into freezing area

• Air velocity between 2.5 and 5  ms^-1

3.2. Cryogenic freezing

•  Liquefied gas such nitrogen and carbon dioxide are used
• Very fast heat transfer
• Create little damage to cell due to small crystals formed
• Use for high value products
• Applications through immersion, evaporite and blown to product or spraying on products

The diagram above shows the benefits using rapid cryogenic freezing method.