Creating consistent, enjoyable food and beverages is impossible without proper mixing, and that’s especially true for cannabis-infused products.

Not only does mixing affect a product’s taste, it plays a large role in its texture, color and appearance—qualities that must be repeated from unit to unit and batch to batch, as noted in a recent whitepaper, “Mixing Equipment and Applications in the Food Industry,” by Charles Ross & Son Company, Hauppauge, NY.

“Consumers expect that the food products they patronize will be exactly the same as the one they had last,” the whitepaper reads. “It is easy to understand that within the food industry a high level of consistency is required not just batch-to-batch but facility-to-facility. In this market, consistency is the backbone of consumer loyalty.”

Achieving uniform consistency depends, in part, on providing equipment suppliers with the information they’ll need to understand a manufacturer’s production process and the intended outcomes. Among the needed information are: 

• Starting, maximum and final viscosity
• Density
• Phases and consistency of raw materials
• Desired characteristics in the end product
• Current method of production and challenges encountered
• Plant layout
• Upstream/downstream processes

Overall capacity—at the start of production and in the future—is another important factor to consider, says Christine Banaszek, sales manager, Charles Ross & Son Company.

“Identify the right size mixer that could meet not only the current need but allow for growth,” says Banaszek. “The minimum to maximum working capacity range varies from one mixer type to another, so discuss with your mixer vendor how to best address your immediate demands and planned future goals.”

Flow vs. Shear

From brownies and cookies to beverages, the specific food application will dictate the type of mixing process and the equipment design required for each manufacturing operation. Mark Hennis, president, INDCO Inc., New Albany, IN, says these processes fall into two main categories. “Mixer manufacturers often determine the correct mixer format for an application based on whether it is for a flow-driven or shear-driven process.”

Hennis notes flow-driven processes involve ingredients with low viscosity that mix easily. This can include multiple liquids or solids that dissolve effortlessly into liquids, such as sugar and salt into water.

“There is a wide variety of standard mixing products for almost any batch size in common containers for this type of application,” says Hennis. “Flow-driven processes are achieved with rotating shaft mixers and impellers that direct the flow downward to create turbulence and circulation in a vessel or tank.”

At the opposite end of the spectrum are shear-driven processes, which demand aggressive action to break down solids or create emulsions from liquids that do not blend easily. “Shear-driven mixers may similarly consist of a rotating shaft but with a sharp, saw-tooth style blade running at relatively much higher speeds,” says Hennis.

Cannabis compounds are lipophilic and may not easily form emulsions, potentially requiring a high-shear process. Banaszek says high-shear mixers from Charles Ross & Son Company are routinely used to prepare emulsions and solutions containing cannabidiol (CBD), tetrahydrocannabinol (THC) and other cannabinoids.

However, a high-shear process might not always be required for a consistent cannabis food product, Hennis notes. “Enough shear can often be generated with other mixers through increased speed and impeller selection.”

Some manufacturers may need a mixing or blending solution that falls somewhere in between. Hennis suggests relying on the expertise of mixer suppliers to select the best equipment for a particular manufacturing operation.

“It is very common to meet people who have a vision but haven’t yet learned how to produce their desired outcome,” says Hennis. “Selecting mixers simply by price or attempting to buy a ‘one size fits all’ mixer are common mistakes. I recommend taking advantage of the years of experience and sound guidance a mixing applications engineer can provide.”

Selecting the Best Mixer

INDCO has worked with customers in the cannabis industry, providing more than 100 quotes to cannabinoid extractors and manufacturers of cannabis foods and beverages, among other products, over the last three years.

Hennis emphasizes the need for durable, easy-to-clean food-grade equipment. “This almost always includes mixers with 316 stainless steel shaft and impeller components that are polished to meet standards for cleanability. The specific type of mixer depends upon their end product, but sanitary finishes and operation in a sealed tank environment are common for mixer customers.”

While sanitary designs are a must, the available options are nearly endless. Hennis cites examples like top- or bottom-mounted mixers, clamp mixers that mount to a bracket on the side of a tank or on a mixer stand, drum mixers, benchtop mixers, floor-mounted mixers, and laboratory stirrers. He notes that laboratory-scale and small-batch pilot equipment are popular among his customers, adding that while some eventually scale-up, most are working under 100 gallons.

Banaszek estimates that Ross began working with customers in the cannabis space about four years ago. Today, the company receives inquiries from customers around the U.S. and Canada.

Understandably, many of those customers start small.

“A lot of starting companies work with kitchen appliances, and we help them translate that process to a scalable mixing operation that could support their growth potential,” says Banaszek.

Banaszek points to Ross laboratory models like the 100LSK-I and the 100LCI-T, which have high-shear attachments available. These top-entering, batch-type mixers feature type 316 stainless steel wetted parts, commercial-grade frames for bench-top mounting and FDA-compliant surface finishes for easy cleaning.

For larger-scale operations, Charles Ross & Son Company often supplies their 400 Series Inline High Shear Mixers which can be used to recirculate on a vessel or produce single-pass results. They are available with a variety of options, including sanitary designs with special seals, highly polished components and sanitary connections.

“Many customers in the food and beverage industry opt for sanitary design Inline High Shear Mixers for consistent results and larger scale but low-maintenance operation,” says Banaszek.

Many other mixer options exist on the market today. IKA Works, Inc. offers a CMX 2000 Inline Mixer that incorporates powders into liquids, mixing these materials reliably and consistently in a batch process. Its multi-level design and unique pumping stage enables processing of high-viscosity products without any additional aggregates. The CMX system is usually supplied with a solid material dosing feeder and mixing containers. Depending on the application and the requirements of the customer, the solid material can be fed via a bulk bag unloader, a funnel, sack-emptying boxes or directly from the bag via a suction lance.

Silverson sells its L5M-A Laboratory Mixer for a range of applications, including mixing, emulsifying, homogenizing, disintegrating and dissolving. With a capacity from 1 ml up to 12 liters and the ability to mix in-line with flow rates up to 20 liters/minute, it offers excellent reproducibility when scaling up to full-scale production and provide an accurate and easy means of forecasting the performance of larger Silverson machines under full-scale working conditions.

No matter the size of the operation, or the type of end product, making quality, consistent cannabis-infused products is not unlike non-infused food and beverages.

“Cannabis may be a relatively new active ingredient in terms of commercialized acceptance, but the basic mixing principles for achieving homogenization and uniform potency remain the same,” says Banaszek.