Mixing, blending, chopping, grinding: essential steps in food preparation. But what can a processor do to beat the heat they generate, especially in large batch mixers?
Even if you’re pre-chilling all your ingredients, the friction that occurs during mixing and blending generates heat. That means you’ve got to remove more BTUs. Otherwise – and especially during the warmer months – you’re likely to experience problems such as:
- Inconsistent product temperatures
- Fat smearing, or plating out
- Bacterial growth
- Product buildup in the blender or mixer
- Sticky or overworked mixtures.
- Variations in cycle times and other problems downstream, such as forming and packaging.
“What?” Processors ask. “I’m already adding dry ice to my mix. Isn’t that enough?”
Adding dry or water ice, or even carbon dioxide snow to the top of a mixer may not cool your product as cost effectively as possible OR produce the highest product quality. A better approach to chilling starts at the bottom of the mixer. Strategically injecting cryogens such as carbon dioxide or liquid nitrogen directly into the mixture rapidly removes heat and delivers significantly better chilling efficiency.
Bottoms up: How controlling mixer temperature boosts quality
Leveraging the thermodynamic properties of liquid nitrogen or liquid carbon dioxide enables processors to chill food faster, more effectively and at a lower cost than other, top-down cooling methods.
Injecting cryogens into the bottom of the mixer uses most of the chilling BTUs of the cryogen as it begins to sublime, or vaporize, blending with the mixture. In contrast, dry ice pellets start to sublime the moment they are made – usually offsite and transported to the customer – and storage and transportation losses can range from 10 to 20 percent. Layers of dry ice also can create uneven temperatures, leading to hot and cold spots within the mix.
And with a bottom injection chilling system, the cryogen is used only as needed, keeping operating costs low. It also eliminates the need for employees to move and shovel water ice or dry ice around the plant, and reduces the risk of batch contamination by microorganisms from the manual ice shoveling or chopping and tempering of frozen meat.
The right tool for the job
The benefits of mixer cooling are greatest for thicker products that require a lot of mixing and blending.
In the meat and protein segments, these include:
- Hamburger and sausage patties, chicken nuggets, ground products, such as meatballs, sausage, gyro meat, meat or bean filling for burritos or tacos, seafood mixes and shrimp paste, and other formed items.
- In the bakery segment, it includes bread, pizza and cookie dough and other thick batters.
- For animal feed or pet food, mixer cooling benefits both wet mixes as well as mixes headed to the extruder that are later dried.
Customization is key
Every plant and food production process is different, so the right engineering is key to matching the system – and cryogen – to the process and maximizing value. For example, although meat and poultry processors have been using carbon dioxide in mixing and blending systems for decades, processors now realize that some products, including raw proteins, cooked bean products, sauces or pastes, are actually better suited t using liquid nitrogen to cool ingredients.
Besides mixers, these cryogenic chilling systems also can be used on cookers or kettles and applied across a range of categories and food items, even including traditionally difficult products, such as dense, high moisture and protein or ethnic food mixes.