Blast Freezer: Ultimate Guide

As the food industry continues to grow, the demand for food storage is increasing. Ensuring the quality of food while storing it has become a key objective for many. To preserve food quality to the greatest extent possible, blast freezers have emerged as a vital solution. This article will introduce you to the world of blast freezers, helping you better understand how they work and how they can be an effective solution for food preservation.

Food Industry

What is a Blast Freezer?

What is a Blast Freezer?

A blast freezer, also known as a quick-freezing freezer, is widely used in the food industry. Simply put, a blast freezer is a specialized low-temperature storage unit that typically maintains temperatures between -25°C and -35°C (-13°F and -31°F). Unlike conventional low-temperature cold rooms, a blast freezer can rapidly lower the internal temperature to the required storage level for food. This quick freezing process helps preserve the quality of the food.

 

Why Use a Blast Freezer?

Impact of Freezing on Food Quality

During the freezing process, food undergoes various chemical and physical changes that can negatively affect its quality. One of the most significant changes is the formation of ice crystals. In a slow freezing process, the moisture inside the food solidifies and forms fine ice crystals. Over time, these fine crystals can grow into larger crystals, which can damage the cellular structure of the food. This damage affects the texture, making the food feel rough. Additionally, the freezing process can disrupt the fiber structure of the food, making it lose its firmness and become mushy. Dehydration can also occur, particularly in fruits, causing them to become dry. Vegetables and meat products may suffer from discoloration.

 

Advantages of Blast Freezers

Preserving Food Quality

Preserving Food Quality

Conventional low-temperature storage units freeze food slowly, often taking 8-12 hours or even longer. This slow freezing process usually fails to maintain the food’s quality. In contrast, a blast freezer can freeze food within 30 minutes to 2 hours. This rapid freezing results in smaller ice crystals, causing less damage to the food’s cells and fiber structure. Compared to traditional low-temperature storage, food frozen in a blast freezer retains its original quality much better.

Enhancing Food Safety

The extremely low temperatures in a blast freezer effectively inhibit the growth of microorganisms, reducing the risk of spoilage or mold. This significantly enhances the safety of the food.

Extending Shelf Life

Compared to conventional low-temperature storage, blast freezers can extend the shelf life of food, reducing the risk of spoilage. This helps prevent waste due to spoiled food and can improve economic efficiency by minimizing loss.

 

How a Blast Freezer Works

How a Blast Freezer Works

A blast freezer operates on principles similar to those of conventional low-temperature cold rooms, relying on both a refrigeration system and an insulation structure to achieve rapid cooling. The key difference is that the blast freezer’s refrigeration and air circulation systems are designed to be more complex and efficient, allowing it to freeze food quickly.

Insulation Structure

The insulation structure of a blast freezer is primarily composed of insulation panels and the cold room door, typically made from PIR (Polyisocyanurate) or PU (Polyurethane) sandwich panels known for their excellent thermal insulation and fire-resistant properties. The thickness of these panels depends on the required temperature inside the freezer. Because blast freezers generally maintain lower temperatures than standard low-temperature cold rooms, the insulation panels are often thicker, sometimes up to 200mm.

Refrigeration System

The refrigeration system of a blast freezer includes a compressor, condenser, evaporator, and expansion valve. By circulating refrigerant through this system, it absorbs heat from inside the freezer, thereby lowering the internal temperature. The insulation structure helps minimize heat transfer between the inside and outside of the freezer, maintaining the low temperature efficiently. Unlike conventional systems, a blast freezer uses more powerful compressors, condensers, and evaporators to enhance cooling efficiency and achieve rapid freezing.

Air Circulation System

Air Circulation System

In a standard low-temperature cold room, cold air is typically blown onto the product surfaces by fans through the evaporator, removing heat from the products to cool them. This method often results in slow and uneven air circulation. In contrast, a blast freezer features a powerful fan system designed for multi-directional airflow, ensuring cold air is evenly distributed throughout the freezer. This forced airflow rapidly removes heat from the product surfaces, quickly lowering the food’s temperature.

 

How to Ensure Optimal Freezing Performance

Blast freezers offer an excellent solution for food preservation, but to ensure that food maintains high quality during the freezing process, consider the following measures:

Proper Storage Capacity

Before designing a blast freezer, it’s essential to consider factors like site size, storage volume, and storage methods (e.g., shelves, pallets, or stacks) to determine the appropriate freezer size. Once the size is determined, adhere strictly to the designed storage capacity during use. Overloading the blast freezer beyond its maximum capacity can cause the internal temperature to rise, compromising the cooling efficiency. Higher temperatures can promote microbial growth, affecting food safety. Overloading can also reduce the lifespan of the refrigeration equipment.

Correct Storage Temperature

Temperature is crucial for maintaining food quality and safety. While blast freezers usually come with temperature monitoring systems, regular manual checks are also necessary. If any temperature fluctuations are detected, identify and resolve the cause immediately to prevent food spoilage or mold growth. This helps reduce waste, save costs, and enhance economic efficiency to some extent.

Proper Installation Location

Proper Installation Location

Choosing the right installation location is crucial for ensuring the efficient operation of a blast freezer and reducing operational costs. Ideally, the blast freezer should be situated in an easily accessible area with convenient transportation, adequate water and power supply, and a clean, pollution-free environment. Additionally, it’s important to ensure there is enough space around the blast freezer for effective air circulation, which aids in heat dissipation and extends the lifespan of the equipment.

Pre-treating Food

Proper pre-treatment of food before freezing can significantly enhance its quality preservation. Using suitable packaging, such as vacuum bags, can reduce moisture loss and oxidation, maintaining the food’s quality. Pre-cooling the food to lower its initial temperature before placing it in the blast freezer can also shorten the freezing time. Once inside the blast freezer, food should be evenly and neatly arranged to allow cold air to fully contact the surfaces, ensuring even freezing and improving efficiency.

 

Conclusion

Whether for food businesses or personal use, understanding and mastering the use of blast freezers can greatly benefit the effective utilization of this essential refrigeration technology. Blast freezers offer a reliable solution for better food preservation. We hope this article helps you make an informed decision when choosing refrigeration cold rooms.

 

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