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Archives for April 2020

How Do Freeze Dryers Work?

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Cold and Dry

When most people think about freeze drying, Neapolitan astronaut ice cream bars are usually one of the first things that come to mind. And yes, it’s true that freeze dried foods are a NASA staple. But freeze drying is so much more than that. Let’s take a closer look at the scientific process and applications of modern freeze drying.

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What is Freeze Drying?

Simply put, freeze drying is the process of removing moisture from a substance without damaging its basic composition. Moisture not only adds weight but also provides an environment for microorganisms to grow and cause spoilage. Removing moisture greatly increases the shelf life of a substance, as well as reducing its size and weight.

Freeze Drying vs. Dehydration

 Freeze drying may sound similar to the dehydration process, but is actually different both in execution and the final product.

Different Execution

The dehydration process turns liquid water into water vapor with the application of some form of heat. Ovens, food dehydrators, or even sun rays are frequently used to evaporate water into the ambient air. This heat, no matter how subtle, causes chemical reactions to occur within the substance being dehydrated. These chemical reactions cause a change in appearance, taste, and smell (such differences are noticeable when comparing a grape to a raisen).

Freeze drying skips the liquid water phase all together. Substances are frozen and then de-pressurized to induce sublimation. Sublimation is different from evaporation because the water will transition directly from a solid ice state to a gaseous state. This process prevents the substance from breaking down on a cellular level and helps retain its composition until it can be re-hydrated.

Different Results

North Slope Chillers graphic on the difference between dehydration and freeze drying

Dehydration removes around 90% of a substance’s water content. Because some moisture remains, bacteria and enzyme activity is only slowed down, but not halted altogether. This moisture reduction does cause some physical changes in color and appearance. The heating process does cause some loss of nutritional value but most foods retain about 60% of their nutrients. 

Freeze drying removes almost all moisture, typically around 99% depending upon the substance. Because of this, freeze dried materials have a much longer shelf life than dehydrated materials. The process also helps preserve its original color, appearance, and molecular composition. Freeze dried materials also retain almost all of their nutritional content.

The History of Freeze Drying

The practice of using the freezing process to remove moisture is an ancient practice of Incan communities living in the Andes Mountains of South America. Townspeople would take local potatoes up to extremely high elevations where they were covered with a cloth and left to the nightly freeze. Come daytime, they would walk on top of the cloth to press moisture out of the tubers and then repeat the process to create their staple dish of chuño. Communities along the Andean Plateau in Argentina, Bolivia, Peru and Chile, still practice this natural freeze drying to this day.

Chuño potatoes

A german pathologist named Richard Altmann began experimenting with laboratory freeze drying on plant and animal tissues starting in 1890. His practices largely went unnoticed until around the 1930s when other scientists began to improve the freezing equipment necessary for freeze drying.

The industrial boom of World War II drove freeze drying innovations even further. Because of insufficient cold chain security, penicillin and plasma shipments were freeze dried domestically so they could be shipped to field hospitals at the war front. From that time forward, freeze drying became a staple practice for military field rations and medicines.

Over the years, freeze drying has become an integral practice for the food and bio-pharmaceutical industries. Freeze drying preserves chemical stability and is frequently used to prepare medicinal tablets, vaccines, and other biologicals so they can be more stable at room temperature and transport more easily.

The 3 Stages of Freeze Drying

North Slope Chillers graphic on the stages of freeze drying

Freezing

The goal of the freezing process is to turn liquid water into a solid without bursting cell walls. This is accomplished by changing chilling speeds and temperatures in such a way that ensures ice crystals form at the right size and shape to preserve biological materials without damaging them. This freezing process can occur slowly (annealing) or quickly (flash freezing) depending upon the material. 

Sublimation (Primary Drying)

During the next phase, pressure within the freeze dryer is reduced to create a vacuum. The temperature is marginally increased so the ice will begin to sublime into a gas. About 95% of the moisture removal occurs during this primary drying period.

North Slope Chillers graphic on the process of sublimation

Desorption

The final phase of freeze drying involves breaking down the ionic bonds that are holding onto the last remnants of water molecules. In order to break these bonds, the temperature is raised higher than it was during the sublimation phase.

Freeze Drying At Home

Freeze drying has become a very popular practice for DIYers, homesteaders, and food prep enthusiasts. It is one of the best ways to store and preserve food and herbs for long term food storage. Freeze drying is no longer just an industrial process, and many are finding ways to accomplish it at home.

Counter size freeze dryer units are increasing in popularity, as are DIY methods involving stacked trays in deep freezers. Consumers are also using their domestic freeze drying prowess to preserve cannabis as more states have loosened restrictions. 

Industrial Cooling Solutions from North Slope Chillers

Here at North Slope Chillers, we specialize in portable industrial strength chillers that fit perfectly into any system without disrupting your current set up. With temperature ranges from 70° F all the way down to -112° F, our chillers can be incorporated into any cooling process. Contact us today at 866-826-2993 or [email protected] to find the perfect chiller for your needs.

Freeze-Drying for Cannabis Preservation

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Freeze drying, invented in Paris in 1906, is a very gentle dehydration process used to preserve high quality foods. During WWII, the process was implemented to preserve blood serum. Since then, freeze drying has become a critical process for preserving foods, pharmaceuticals, and a wide range of other products–even cannabis. Cannabis growers are turning to freeze dryers to help them process their crops in response to the rise in the demand of dried cannabis flowers.

Learn more about Cannabis Extraction

Freeze Drying Cannabis: Basic Science and Benefits

Freeze-drying occurs when the solvent (usually water) and/or suspension medium is crystallized at low temperature and removed by sublimation (the direct transition from a solid state to gaseous state without melting). The technical term for this process is Lyophilization.

Three Stages of Freeze Drying Cannabis

There are three stages in the freeze drying process: freezing, sublimation drying, and desorption drying. The freezing phase is the most important part of the freeze-drying process. Rapid freezing is critical and helps eliminate the formation of large ice crystals, which deteriorate the final product quality. 

During the drying phase, a high vacuum reduces pressure, and heat provides energy needed for the ice to sublime. This initial drying phase removes about 95% of the water present. This slow step can take anywhere from several hours to two days. Too much heat during this phase could damage final product quality.

In summary, the process runs as follows:

  • Deep-freeze:  This brings cannabis buds down to – 40°F or below. The colder you can get your product, the fresher.
  • Sublimation:  This part of the process turns solid ice straight to water vapor, skipping the liquid phase. A vacuum pump then kicks in, sucking out the water vapor.
  • Final dry:  Now the product is returned to room temp (70-80°F), taking the last bit of water content out of the buds.

Freeze-dried products typically contain between 1% and 4% moisture. These products can be stored between 6 months and 3 years in polybags and 25 years or longer in cans.

Freeze-Drying Cannabis Flowers : How it Started

“When someone walks into a dispensary to look at flower, they want a bud that looks fresh,” says Rich DeLong. “No one wants to buy something that looks shrunken or desiccated.”

Rich DeLong has spent nearly three decades producing freeze-drying equipment that allows florists and other botanical professionals to preserve their products.  When approached in 2017 about the prospect of freeze drying cannabis, he started the challenge with a small batch–which failed miserably.

Cannabis flowers are delicate, and the oils, minerals, and terpenes therein are extremely fragile. With this in mind, DeLong created a method for freeze-drying cannabis that maintained an oil and terpene content equivalent to that found in buds that had been left to hang-dry. Hang drying took 18 days, but the freeze-dried plants were preserved and ready for packaging in less than 24 hours.

Freeze-Drying Flowers

Freeze-dried buds start out as fresh flowers.  After placing the buds into an extremely cold chamber, sub-zero temperatures quickly freeze the flowers, transforming the water inside to ice crystals. Once those crystals have formed, operators drop the pressure inside the freeze-dryer, to create the vacuum necessary for sublimation drying.  That sublimated water vapor is pulled by the vacuum into a colder condensation unit. All that remains is a freeze-dried flower that retains its taste, color, and shape.

“Freeze drying could revolutionize the way marijuana is packed and presented. Imagine a bud looking the same inside a package as it did coming off of the plant,” says Arnovick. “You remove the water, but keep the structure. There’s no mineral loss, no vitamin loss, no terpene loss—just a beautiful flower, ready to smoke,”  said Travis Arnovick.

From Farm to Freezer

North Slope Chillers graphic comparing hang drying and freeze drying cannabis

“A couple years ago, if you told someone you were going to freeze 100% of your crop, they’d tell you you were crazy. Now, we’re seeing 100% frozen harvests, and really large farms: 8,000-pound harvests. It’s totally taken over,” said Ben Grambergu at Grambergu Marketing in Northern California.

Consumers are driving the trend for frozen and freeze-dried plants. Farmers have responded by buying up industrial freezers—plus using dry ice in the fields—and are sending the frozen crops straight to extract labs, skipping the traditional hang-to-dry harvesting process.  Freezing preserves terpenes that would otherwise be lost to weeks of drying and curing.

Harvest Right’s Freeze-Dry Process

Freeze-drying cannabis has been around for a while and it’s becoming increasingly popular for small- and large-scale growers. Salt Lake City’s Harvest Right’s Pharmaceutical units shorten the curing process to just 24-36 hours, and are affordable and aimed at both small- and large-scale growers, and even homegrowers.  These units preserve buds and terpene profiles better than standard curing because they don’t use heat. Because of the quick cycle of the units and because the curing happens in a controlled environment, there’s a reduced risk of mold or mildew.

Process Cooling and Cannabis

It’s clear that the future of cannabis production directly involves cooling plans and the right equipment to preserve farm-fresh products. For more information about process cooling and cannabis, click here.

Manufacturing During a Pandemic

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Uncharted Territory

The COVID-19 pandemic has introduced a slew of challenges for the industrial community. With whole economic sectors shuttered, bottlenecks and deficiencies in the supply chain, drastic changes in consumer behavior, roller coaster stock market figures, collapsing oil demand, furloughed work forces, and new health and safety restrictions…companies are reeling to steady their ships.

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The full breadth and complexity of these challenges have already caused immense implications for even those companies who had contingency plans on file. Typical emergency plans usually cover power outages, natural disasters, and security compromises. However, the current COVID-19 situation is changing so rapidly, the manufacturing sector is struggling to protect themselves during such a widespread and extended global crisis.

Manufacturing Ramifications

The National Association of Manufacturers conducted a survey (from Feb.28th – Mar 9th) among leading manufacturers to get a feel for how the industry will be affected by the current pandemic.

North Slope Chillers graphic showing how COVID-19 is affecting manufacturers

78.3% of those surveyed said the COVID-19 epidemic will likely have a financial impact on their business. 53.1% anticipate a change in their operations in the coming months. 35.5% are already facing disruptions in their supply chain.

Unprecedented Challenges

Manufacturers are trying to find ways to allow employees to work remotely, fill orders on time, maintain their product quality while making compromises, store materials longer than usual, create safe distances in worker dense spaces, and prepare for supply chain adjustments.

The food and beverage industry is one sector that has experienced the most upheaval as the supply and demand chain has developed some unfortunate kinks. While grocery store suppliers are ramping up production to meet demand, food suppliers that cater to restaurants, theme parks, hotels, cruise liners, and schools have found demand cease almost overnight. These suppliers have been left with excess inventory and lack the cold storage capacity to store it while finding new customers. The result is a staggering increase in food waste.

Necessity is the Mother of Invention

During the years following the attack on Pearl Harbor, American production and manufacturing changed completely. Clawing its way back from a period of inactivity during the great depression, the country suddenly found specific industrial demands skyrocketing. Some manufacturers simply ramped up production, while others switched gears entirely.

Car manufacturers began churning out fuselages, guns, and tanks. Sheet metal factories pivoted to solely producing parts needed for constructing ships, planes, and other defense vehicles. Consumers rationed and planted victory gardens so more domestic food supplies could be diverted to support our armed forces. The majority of the country unified their priorities, and refined their focus to the war effort.

Switching Gears

As global needs and consumer habits have completely changed in the last several weeks, some manufacturers have resurrected a good old “war time” mentality and shifted production practices. Dozens of craft distilleries have re-directed their alcohol production from spirits to hand sanitizer. Fashion designers and clothing manufacturers have set to work sewing PPE (personal protective equipment) for health care workers.

Family history geneticists have turned their saliva based ancestry kits into more affordable, FDA approved COVID-19 tests. Vacuum manufacturers have pivoted their technology to producing ventilators. Automobile factories have rededicated their production floors to creating face shields. The tech industry is even redirecting computing power to epidemiology labs to help them run molecular sequencing programs more quickly.   

Selling Raw Materials

Some manufacturers have adjusted by selling raw materials directly to clients instead of a finished product. For example, bakeries and restaurants that are restricted to take out orders only, have started selling raw ingredients to customers who have been unable to find the products they need on grocery store shelves. Just the other day, I personally purchased yeast and a 25 pound bag of flour from my local bakery because my grocery store had been out for weeks.

Weathering the Storm with Temperature Control

Most manufacturers have thorough supply chain time tables that help them communicate with suppliers, order and store raw materials, manage manufacturing timelines, ship finished products, and make or collect payments. Depending upon the industry, many manufacturers have had to throw out their old rule books and adapt to a business world that is constantly in flux. Let’s take a closer look at some practices that can help manufacturers protect their inventories and operations during this difficult time.

Increase Cold Storage

One of the most effective ways manufacturers can protect their business during this difficult time, is to increase their cold storage capacity. As spring turns into summer, hotter temperatures are already on their way. These temperatures threaten thermally sensitive raw materials and drastically reduce their shelf life and viability. The COVID-19 pandemic has made manufacturing input and output timelines extremely unpredictable. Adding extra cold storage capabilities to your facility will give you greater flexibility and protection.

For example, food suppliers work within a very delicate timeline to keep their products safe and viable from farm to table. Any disruption in the cold supply chain leads to costly waste. Bio and pharmaceutical companies adhere to even stricter cold storage and transportation guidelines. 

According to the CBRE, an additional 75-100 million extra square feet of refrigeration and freezer storage will be needed nationwide to keep up with normal perishable food and pharmaceutical demands. The COVID-19 pandemic will greatly accelerate these cooling needs. 

Greater Automation

Another important tool that manufacturers can use to weather the storm is increasing their use of automation. Most machinery and equipment require temperature controls to prevent overheating and breakdowns. Recent social distancing regulations and workforce reductions have shown how difficult it can be to keep things running smoothly with as few on-site workers as possible. Smart controllers offer manufacturers remote access to their temperature control equipment. By tapping into the Internet of Things (iOT), companies can remotely keep equipment running efficiently, protect temperature sensitive materials, and reduce the number of on-site workers.

Emergency Temperature Control Solutions From North Slope Chillers

During these uncertain times, it is important to find certain things you can depend on. Here at North Slope Chillers we are proud to offer efficient and expertly engineered cooling solutions that keep your operations up and running.

Graphic showing emergency cooling solutions from North Slope Chillers

Our industrial chillers are portable and easy to install without disrupting your current setup. With expansive temperature ranges from 75°F all the way down to -112°F, you can be sure to find the exact cooling range for your needs. We can protect your temperature sensitive materials during supply chain disruptions, keep your equipment cool and running efficiently, and provide peace of mind during turbulent times.

In addition, with our Beacon smart controllers, we can streamline your temperature control needs and allow you remote access by putting cooling power right at your fingertips. With world class customization options available, you can be sure to find the perfect cooling solution for your needs. Contact us today at 866-826-2993 or [email protected] and find out how we can help you get back to business.