Packaging Molten Products, Hot Fills

Not all liquid products stay liquid after they have been packaged. Products like candles will be melted to allow for the product to be filled, but will then revert to a solid state before they reach the consumer. Other products will be heated to reduce the viscosity and allow for a more free-flowing liquid during the filling process. While the filling machines will require some modification to keep products warm, other equipment exists that provides an ideal solution for those working with molten products or hot fills.


Obviously, temperature control is a very important component of filling molten or hot products. For many of the products, the temperature must be kept at a constant in order to ensure a consistent flow. A change in temperature anywhere along the product pathway can result in a change in viscosity for many of these products, which can lead to a change in flow. Such a change can lead to inconsistent fills. Cooling prior to reaching the bottle can also clog tubing or nozzles and also have an effect on the reliability of the machine. Other components, such as positive shut off valves and anti-drip nozzles also protect against the product solidifying in an area that could cause production shutdown.


When a product is filled hot, there will still be other packaging aspects that need to be completed. Common sense tells us that the package will still need to be capped or otherwise sealed once product is introduced. It is also common for products to be labeled, coded and sometimes even bundled after the liquid is introduced. However, hot product can cause inconsistency in these later packaging stages. To protect against bad seals, wrinkled labeling and other issues, a cooling conveyor will often be used immediately after the filling process to allow product to solidify and lower in temperature. Cooling conveyors may be long, straight conveyors or multi-level, multi-lane systems to save space. These conveyors may also include fan units to quicken the cooling time.


Some molten products may solidify rather quickly, resulting in an uneven shape or a look that is not symmetrical. In these cases, a reheat station will be used to once again liquefy the product and allow it to settle evenly before final packing and shipping to the customer or the shelf.

Outside of the items listed above, molten products and products that require a hot fill will typically be packaged in the same manner as any other liquid product. From capping, labeling, coding and bundling, the machines will not usually require modification, as long as product is filled and cooled in the manner described above. If you would like to learn more about packaging molten or hot fill products, contact a Packaging Specialist at Liquid Packaging Solutions, Inc. today.