Hot filling technology refers to filling liquid foods while they are still hot after sterilization, utilizing the heat of the product to sterilize the inner surface of the container. Hot filling can be divided into two types: high-temperature hot filling and medium-temperature filling followed by pasteurization at 65℃~75℃.
Hot filling technology does not require separate sterilization of bottles and caps; simply maintaining the product at a high temperature for a sufficient time is sufficient for sterilization. Hot filling requires PET bottles to withstand temperatures of 85℃~92℃ while maintaining good heat resistance. Therefore, thicker PET bottle walls are used, with ribs to prevent heat shrinkage. However, this significantly limits the freedom of bottle design, and heat-resistant PET bottles and caps are more expensive.
In terms of process flow, hot filling technology does not require separate sterilization of bottles and caps before filling, but a bottle inversion process is required after filling, using the heat of the product to sterilize the caps. For medium-temperature hot filling, subsequent pasteurization is also necessary.
The longer the heat treatment time, the greater the impact on the quality and taste of the beverage. Because materials in hot-filled products are exposed to high temperatures for extended periods, heat-sensitive nutrients (such as vitamins) are significantly lost, and the product's taste and color are also greatly affected. In terms of production costs, hot-filling requires heat-resistant PET bottles and caps, which are more expensive and heavier than ordinary PET bottles. However, in terms of equipment costs, the investment cost for a hot-filling production line is lower than that for an aseptic cold-filling production line.
The filling temperature for hot-filling is 85~88℃.
