What is Double Pass Food Grinding

In the world of commercial food production, grinding is a critical part of many manufacturing processes. Single pass food grinding on it’s own is not enough to produce many of the products we know and love, here’s why: The amount of work you can do in a single pass on size reduction equipment is limited – both by the properties of what you’re feeding and by the target size of the material. Because of this, some material requires double pass grinding. In this post, we’ll discuss the benefits of double pass grinding; where it’s used in commercial food production, and which machines are best for companies who require double pass grinding. Let’s dive in.

First Things First: Why Double Pass Grinding?

Clear Bowl filled with Ground nuts Sometimes, food grinding can’t be a “one and done” process. When it comes to size reduction, the laws of physics dictate that you can only do so much work in a single pass. A classic example is in the reduction of a twenty-pound wheel of parmesan cheese.  Say you need to grate this large wheel of cheese for pizza topping. Pizza topping requires a nice, fine grind with no chunks or large clumps of product. If you try to reduce the entire wheel in a single pass, though, you’ll end up with one of two outcomes: you’ll either overheat your material or destroy your machine.  Instead, begin by reducing the wheel of cheese into small pieces via an initial grinding pass – chunks of  0.75”, for example. Once you’ve made a single pass and reduced the material to 0.75”, you can take this output and grind it once again, through a different machine, to create a smaller particle size. This is called double pass grinding. While double pass grinding is common in commercial uses, it’s also utilized by at-home chefs grinding meats and other products.  The process of double pass grinding is essential for a few reasons. The first and most obvious is that it reduces the load on both machines during passes. The amount of load it takes to process a large product directly into its final form factor can be massive. For example, the rotating imbalance of flinging around a 20 pound block of material is enormous and potentially damaging. The objective for companies is to get the material through the mill as quickly as possible without negatively impacting the product or the machinery. Double pass grinding can greatly increase the efficiency of the size reduction operation. This consideration is especially critical for a product which will melt under high heat loads. 

Which Foods Require Double Pass Grinding?

Double pass grinding is more widespread than you might imagine. Even machines that grind things to super-fine dimensions (think chemical and pharmaceutical processing, for example) requires a head start. As powerful as some machines are, they often can’t take a massive piece of material and grind it down to something superfine in a single pass.  The flour industry is a perfect example of the need for multiple pass grinding. Some flour mills use seven-pass roller mills, for example. These mills process the same material again and again, at an increasingly finer particle size, until it reaches the desired granularity.  Additionally, double pass grinding is exceptionally useful in reducing clumps, lumps, and leftover large particles in many different foods. 

Can You Double Pass on the Same Machine?

It is possible to double pass a product on a single machine. The only consideration is that you cannot undergo the second pass with the same sized screen if you want a finer product. Instead, you must switch to a finer screen, which will effectively deliver the same results as a multiple pass machine, processing the material at an increasingly smaller particle size until it reaches the desired consistency. 

Double Pass Food Grinding: A Critical Addition to Size Reduction Processes

In the world of grinding, double passing is an important and common approach to creating a super fine finished product. By running material through several food grinding machines or using progressively finer screens on successive passes, manufacturers can create the particle size they want for their product without causing excessive heat or load on their machines during the process.  If you’d like to learn more about double pass food grinding, or which machines are ideal for double pass food grinding, contact Corenco today. Our staff will be happy to help.    55-gallon drums are a convenient way to acquire frozen product, but can be a pain in the neck to deal with.  Not only are these drums large and unwieldy to move around, but they take a long time to thaw. At most plants, food processing companies deal with this problem by leaving drums of material outdoors to thaw. The big issues with that solution are that they don’t let them thaw out long enough and the center remains frozen. Alternately, companies let them soften too long, risking spoilage. If you have a frozen kernel in the middle of the drum, the core will mostly be water. Orange juice concentrate is a great example: the water freezes before the sugar, so you wind up with a frozen drum of juice that’s mostly sugar on the outside with a hard kernel of ice in the middle. To transform it back to orange juice, you then have to break up the ice ball, add water, and mix.  Introducing size reduction equipment not only dramatically speeds up the thawing process, but also prevents damage from under-thawed material in downstream processes. 

The Quickest Way to Thaw 55 Gallon Drums of Material

Frozen cherries, raspberries and black currantsThe easiest way to deal with these large drums of material is to conduct the entire process while the material is still frozen. Unfortunately, there’s not much equipment out there that can do it. Most rotary chippers designed for this are ineffective and slow. Other pieces of equipment, like the Reitz Extractor, for example, serve different purposes. The Extractor is a large, stainless steel, high-capacity, meat grinder. While the machinery is robust, it is too expensive or unsanitary for many companies.  Because of that, some companies use Crushers, which is what we manufacture here at Corenco. Crushers are a less costly method of processing large amounts of frozen material, from 5-gallon buckets to 55-gallon drums. These Crushers reduce content down to softball-sized or smaller chunks. Many companies utilize a subsequent milling step to further reduce their material to a “snowcone,” or a pumpable, slurry.

Why Crushers Are So Helpful

Crushers are versatile machines that were designed specifically for reducing large bulk products to manageable sizes. This allows manufacturers much more flexibility in their downstream processes. By running your materials through a Crusher or Grinder, you can streamline production and increase capacity. For an example of these machines at work, check out this video of a Corenco C24 crusher grinding a 55-gallon drum of frozen juice. As you can see, running the ingredient through the size reduction equipment takes a process that would require hours to thaw naturally and reduces it to just a few seconds. The product will then thaw out evenly and be ready for additional processing. 

Thaw Frozen Food the Easier Way

Size reduction improves the efficiency and productive capacity of processing lines that involve large bulk/frozen products. Corenco’s Crushers can be found all over the world tirelessly performing size reduction with minimal upkeep and maintenance.   Our technology helps streamline the thawing process and ensures faster processing times for our customers, and Crushers by Corenco will go a long way to improve and enhance your product thawing efforts.   If you’re interested in investing in machinery that could streamline your thawing or bulk product size reduction process, contact Corenco today. We manufacture many lines of durable, reliable size reduction equipment meant for a wide variety of applications. We’re happy to help you navigate our selection and find the products that are perfect for you.