A Blast Freezer freezes fresh or partly cooked food much faster than an ordinary home freezer, locking in the key qualities and nutrients of the food. So that after defrosting, the food appears like it was never frozen, and the taste, texture, colour and overall look are uncompromised.

Let's get technical...

When you freeze food (or anything else for that matter) the water inside crystallises into ice. The longer the freezing process takes, the larger the ice crystals. In a Blast freezer, the temp of the food is lowered to -20 degrees celsius in just 4 hours, as opposed to taking 10-72 hours in a normal freezer.  Rapid freezing causes the crystals formed to be very small, which does less damage and preserves food at a higher quality. 

Aside from the integrity, quality and taste of the food, blast freezing also offers a health and safety benefit in that extreme cold slows down the growth of bacteria so that there is a greatly reduced risk of contamination.

Finally, a blast freezer allows you to put the food into it when freshly cooked and still hot (with a normal freezer, you need to cool it down first) and this alleviates any sourness that may develop.