The difference between hot and cold canning of beverages and their sterilization

What is hot filling?

Hot filling is to fill the product into the bottle at about 90 degrees after high-temperature sterilizing, and after screwing the cap, use the temperature of the material itself to carry out the final sterilizing of the bottle and cap. This way, the product stays at high temperatures for a longer period, which causes more damage to its taste and nutrition. Common hot-filled drinks: PET bottles are harder, thicker, and generally hot-filled; roof packages are also part of the hot filling. 

What is cold filling?

Cold filling is the product of ultra-high-temperature sterilization cooled to room temperature in an artificially created aseptic environment, filling into bottles or cartons sterilized with hydrogen peroxide; the cap is also sterilized by hydrogen peroxide screwed tight. Cold filling has less impact on the product's taste and nutritional quality, and PET material use is less, but the equipment investment is about one time more than hot filling. The aseptic cold filling is the concentrated juice jammed after sterilization, cooling irrigation into 220 liters of vats, with a shelf life of more than one year. Common cold filling drinks: general milk, bottled water, Huiyuan juice, and other cartons of pure fruit juice drinks are basically cold filling.

II. Hot Canning and Cold Canning Process Difference

1. Process flow

• Hot canning process:

Raw material processing: fruits, tea, and other raw materials are cleaned, juiced, and filtered. 

Heating sterilization: the beverage is heated to 85-95 degrees Celsius and kept for some time to kill microorganisms. 

Filling and sealing: Fill the beverage into the pre-sterilized containers at high temperature and seal them immediately. 

Cooling: The sealed containers are quickly cooled to prevent the beverage from being in a hot state for a long time and affecting the taste.

• Cold canning process:

Raw material processing: After the raw materials are processed, they are mixed and blended in a low-temperature environment.

Pre-cooling: The beverages are cooled to 4-10 degrees Celsius for cold canning. 

Sterilization: Containers and lids are sterilized. Commonly used methods include peroxyacetic acid spray and UV irradiation. 

Filling and sealing: Filling cooled beverages into containers in an aseptic environment and sealing them immediately. 

Secondary Sterilization: Some cold canned beverages are sterilized twice after sealing to ensure product safety.

2. Applicable products

Hot canning is suitable for non-carbonated products such as fruit juices, tea beverages, sports drinks, functional beverages, and so on. These products can maintain stability at high temperatures; high-temperature canning can effectively kill microorganisms. 

Cold canning suits carbonated drinks, beer, milk, lactic acid bacteria drinks, etc. It can maintain the beverage's flavor and carbonation bubbles while avoiding the impact of high temperature on the quality of the product.

Sterilization Measures of Hot Canning and Cold Canning

1. Hot canning sterilization
Heating sterilization: The main sterilization method in hot canning is heating the beverage to 85-95 degrees Celsius. This temperature is sufficient to kill most microorganisms and ensure the safety of beverages.

Container Sterilization: Containers are steam or hot water sterilized before canning to ensure no microbial residue inside. 

2. Cold Canning Sterilization

Sterilization of containers and lids: During the cold canning process, containers and lids must be strictly sterilized. Common sterilization methods include peracetic acid spray, UV irradiation, and steam sterilization. 

Aseptic filling environment: Cold canning must be performed in an aseptic environment to prevent microorganisms in the environment from contaminating the beverage. Aseptic filling equipment and sterile air filtration systems are key technologies for cold canning.
Secondary Sterilization: Some cold-canned products undergo a secondary sterilization process, such as pasteurization, after sealing to ensure product safety.

Hot canning and cold canning have their own advantages and scope of application in beverage production. Hot canning, through high-temperature sterilization and filling, is suitable for non-carbonated beverages and has the advantages of thorough sterilization and simple process; cold canning, through strict sterilization measures and aseptic environment, is suitable for carbonated beverages and beverages that need to be preserved at low temperatures and is able to maintain the flavor and quality of beverages effectively. In actual production, choosing appropriate canning methods and sterilization measures is crucial to ensure the quality, safety, and taste of beverages.