blastfreeze

Blastfreeze, also written as blast freezing, is a rapid freezing process that uses a high-velocity stream of cold air to freeze products quickly, typically within a blast freezer or tunnel. By removing heat from the product's surface and interior through convection, it aims to form many small ice crystals, which helps preserve texture and quality after thawing.

How it works: air at low temperature (commonly around -20 to -40°C) is blown across the product on perforated belts or racks. The cooling rate depends on air temperature, velocity, product size, and load density. The goal is to bring the product's core to a suitable frozen state, often reaching -18°C or colder for long-term storage.

Equipment and setups: blast freezers can be pass-through tunnel configurations or walk-in rooms with high-flow fans. Modern systems use programmable controls, humidity management, and insulated enclosures to optimize heat transfer and minimize dehydration.

Applications and benefits: widely used in the food industry to freeze fruits, vegetables, meat, seafood, prepared meals, and bakery items. Benefits include reduced ice crystal growth, better texture and appearance, reduced drip loss, and extended shelf life. It is also used in some pharmaceutical and biotech contexts to preserve heat-sensitive materials, though food applications are predominant.

Limitations and considerations: high capital and operating costs, energy use, and the need for careful load planning to ensure uniform freezing. Improper air temperature, humidity, or airflow can cause freezer burn or uneven textures. Post-freeze handling and proper storage at -18°C or lower are essential to maintain quality.