Hot beverage filling vs. sterile cold filling-1

Sterile cold filling refers to the cold (room temperature) filling of beverage products under sterile conditions, which is different from the commonly used high-temperature hot filling method under normal conditions. When filling under sterile conditions, the parts on the equipment that may cause microbial contamination of the beverage are kept in a sterile state, so there is no need to add preservatives to the beverage, and there is no need to perform post sterilization after the beverage is filled and sealed. This can meet the requirements of a long shelf life and maintain the taste, color, and flavor of the beverage.

■ 1 ■ Different filling processes
Hot filling: The product, bottle, and lid are sterilized. After the product is filled into a PET bottle, the center temperature of the product is measured to be 88 degrees. High temperature products are sterilized by pouring the bottle and then cooled to room temperature in a cooling machine;
Cold filling: Sterilize the product, bottle, and lid separately, fill them in a sterile environment, and completely seal the product and bottle before leaving the sterile environment.

■ 2 ■ Differences in process flow
The biggest difference is the heating time of the product.
Aseptic cold filling: The product uses UHT ultra-high temperature instant sterilization, then quickly cools to room temperature, and is stored in a sterile tank for filling at any time;
Hot filling: The product adopts UHT high-temperature instantaneous sterilization, and then cools to above 90 degrees; After infusion, the product temperature is 88 degrees. Due to the prolonged heating time of the product, it has a certain impact on color, flavor, nutrition, etc.

■ 3 ■ Different production line configurations
Hot filling:
1. When the Filling Machine malfunctions and stops, the product will reflux inside the sterilization machine, and repeated sterilization will cause certain damage to the flavor and nutrition of the product;
2. Equipped with large cooling equipment to cool the filled products to room temperature.
Sterile cold filling:
1. After the product sterilization is completed, it is temporarily stored in a sterile tank and there will be no repeated sterilization;
2. The product is filled at room temperature and does not require cooling equipment.

■ 4 ■ Differences in PET bottles
Hot filling: The process requires PET bottles to withstand high temperatures above 92 degrees Celsius, so the PET bottles used should have the following characteristics:
1. Bottle wall thickness, with clear bottle wall ribs to prevent thermal shrinkage
2. Bottle mouth crystallization, the bottle mouth does not deform during infusion and cooling processes
Sterile cold filling: The maximum heat resistance temperature is 60 degrees, so lightweight PET bottles and standard caps can be used, greatly reducing the cost of bottles and caps.

■ 5 ■ Different production lines
Hot filling: The Bottle Blowing Machine has a slow speed and high power consumption. Under the same production capacity, the investment is much higher than that of the cold filling bottle blowing machine (excluding bottle preform equipment);
Sterile cold filling: The blow molding machine used for sterile cold filling has a fast blowing speed and low power consumption. However, the sterile cold filling process is complex and there are many auxiliary filling equipment. Overall, the initial investment of a sterile filling production line is higher than that of a hot filling production line.