Liquid Packaging Essentials: 3 Important Details You Must Know
Whether it's sauces, thick creams, gels, or even water, liquid packaging is quick, clean, and easy using modern flexible packaging machines.
If you're looking to automate your liquid pouch packaging, there are three main things your packaging equipment manufacturer or integrator needs to know to provide the best liquid packing machine for your application.
Viscosity is the Name of the Game in Liquid Packaging
Viscosity is defined as a measure of a fluid's resistance to flow. It describes the internal friction of a moving fluid. A liquid with higher viscosity, such as icing or molasses, resists motion because its molecular makeup gives it a lot of internal friction. A fluid with lower viscosity, such as water or corn oil, flows easily because its molecular makeup results in very little friction when it is in motion.
The mathematics required to calculate viscosity is much too involved for a packaging blog and can be most easily measured with special equipment. However, a simplified formula for measuring viscosity is as follows:
viscosity = shear stress / shear rate
The answer is usually expressed in centipoise (cps). Water is the standard at 1 cps. A liquid product like honey would have a viscosity of 2,000 - 3,000 cps. Condiments like ketchup or mustard have a viscosity of 50,000 - 70,000 cps.
CSC Scientific Company Inc., a provider of measuring equipment, explains that in the Consumer Packaged Goods (CPG) world, viscosity affects the rate at which a liquid product travels through a pipe, how long it takes to set or dry, and the time it takes to dispense the fluid into its packaging.
When it comes to selecting liquid packing machines, viscosity of the product is a vital detail and must be accurate. Viscosity determines the type of product filler used: It must provide the right amount of force to induce flow, but not so much that the packaging will overfill.
Fill Temperatures Affect Viscosity of Liquids
The temperature at which the liquid product will be filled is very important to the packaging project, specifically when it comes to the product filler. When heated, most liquid products flow more readily. Picture the consistency of frosting or motor oil as it is heated; its viscosity lowers significantly and it becomes much more free-flowing. To provide the most efficient liquid packaging solution, providing an accurate fill temperature is a must.
Size Matters When it Comes to Particulates
Liquids like salad dressings, soups, and sauces often contain particulates. These particulates are usually spices and flavor additions like small vegetable pieces. Particulates can be suspended in the liquid product or they can settle toward the bottom of the fluid.
When packaging liquids with particulates, special care must be taken to accurately describe and measure their average size and general properties. The presence of particulates will determine the type of product filler your liquid packaging solution will require for the most accurate and unimpeded dispensing.
Liquid Packaging Solutions
Viking Masek has installed a variety of packaging equipment in facilities for liquid packaging projects like:
- Hot fill bulk soups with particulates
- A variety of liquid products filled into new premade STANDCAP pouches
- Filling and sealing sauces into premade stand-up pouches
- Liquid and gel cold packs for meal kits and medical/therapeutic use
- Small sticks or sachets of condiments, flavor enhancers, and cleaning solutions
Visit our liquid packaging machine hub to learn more about the different types of equipment used for packaging fluid products.
Liquid Packing Machine Project Worksheet
Make sure your liquid packaging solution is spec'd correctly - download our free planner that will help you define over 50 key details vital to the success of your equipment acquisition:
Originally published 8/31/2016, updated 6/5/2018.