Blast Freezer: Working & Applications

What is a blast freezer?

A blast freezer (also known as shock freezer or flash freezer) is a special type of freezer storage which very rapidly freezes the food stuff or fresh produce at extremely low temperatures. This is air blast freezing.

Rapid freezing prevents the formation and growth of harmful micro-organisms in the food by neutralizing them.

Blast freezers preserve the food at extremely low temperatures (-18°C to -45°C) and for long duration whereas blast chillers cool down the food rapidly up to 3°C but only for shorter duration of preservation after which the food stock is taken out to be cooked & served.

Working principle of blast freezers

Freezing crystallizes the water inside food into ice crystals. Ordinary freezers take longer to freeze the food, consequently the ice crystals formed inside food are larger. When this ice thaws, it distorts & even damages the cell structure of food by causing phenomena like cell bursting. It affects the quality and texture of food.

Blast freezer, on the contrary, freezes the food very rapidly, and at even lower temperatures, where the blowers pass blasts of very cold air over the surface of food. The ice crystals thus formed in the food are comparatively smaller.

When food is taken out of the blast freezer (or blast chiller) and ice crystals thaw, cell structure of food is still preserved, thereby minimizing the alteration in its quality and texture.

One important aspect is to not store too high a volume of hot food inside the blast freezer which will result in higher internal temperature leading to a warmer blown air. The freezer will take longer time to first cool this stagnant air, thereby delaying the entire cooling process.

Some of the best blast freezers use movable trays which allows to customize the positioning of food to ensure its even cooling.

Blast freezing applications

Blast freezers are commercial freezers made exclusively for business owners. They need to freeze their products due to the growing production and product demand. Some of the applications of blast freezers are listed ahead.

1. There are industrial blast freezers used in commercial units like cold storage companies.
2. Commercial kitchens, big restaurants, hotels etc. use blast freezers as well as blast chillers to safely store food stock, cooked food and meals. Blast chillers lower the temperature of a large amount of food stock by blowing extremely cold breeze throughout the storage. This eliminates harmful bacteria from the food stock and preserves it. You can place a large stock of food in such chiller if you have to serve from it on short notice repetitively.
3. Blast freezing is also employed in confectioneries to preserve large stocks of desserts/pastries which require cooling e.g. pies, cakes, puddings, ice-creams etc. Proper chilling enhances the taste and texture of the dessert
4. Fishing industry & meat suppliers finds great utility in blast freezers. Sea-food decays fast if not properly preserved. In order to supply raw sea-food to distant markets of the world without compromising the quality of the haul, storing the sea-food in such freezers halts the decaying of stock for a long time.
5. Vaccines contain active ingredients that are used to stimulate immunogenic response when administered to a patient. Maintaining the stability & viability of the active ingredient during production, distribution and administration of the vaccine is a huge challenge to vaccine manufacturers. Storage in a blast freezer ensures highly reduced degradation of the active ingredient making it more stable and viable for longer time.
6. In dairy industry, blast chillers are used to preserve dairy items (like curd, butter, milk, flavored milk, clarified butter, cottage cheese etc.) in bulk so that they can be transported to distant places without losing quality.

Pros and cons of blast freezing

Some of the pros of blast freezing are enumerated as follows:

1. Blast freezers arrest contamination of food, thus preserving food’s integrity, quality and flavor & also safeguarding its nutritional values.
2. It protects delicate food preparations (like pasta, soufflés & fruit extracts) since the structure of food is preserved in blast freezing.
3. Blast freezing pre-empts growth of harmful bacteria and other micro-organisms, ensuring 100% food safety.
4. Blast freezers are ideal for storing large batches of leftovers thereby reducing food wastage in restos.
5. Large amount of space among the trays of blast freezer ensures cold air is circulated in smooth and laminar fashion around the trays making the freezing quick and efficient.Also, dedicated compartments inside the freezer can be used to freeze store different food items for different time duration.

There are seemingly no cons for blast freezers. For domestic usage where food is preserved for lesser number of people & is consumed within short duration, a refrigerator may seem to be a more prudent choice than the blast freezers whose build, larger storage capacity, cost & power efficiency in the long run makes them best suited for commercial utility.

With the passing years, Industrial Refrigeration Pvt. Ltd. (IRL) has tied-up with global companies, like GEA Group, to introduce the latest refrigeration technologies and practices in India such as paraffin wax freezers for refineries, snow rooms, ice skating rinks, dairy refrigeration, abattoir refrigeration and modified & controlled atmosphere cold stores.

IRL caters to industries like food processing, hospitality, chemicals, oil and gas, supermarket & entertainment. Feel free to check our products and IRL will realize your refrigeration requirements.