Freeze Dryers and Bubble Hash: Vacuum Drying vs. Freeze Drying

The importance of freeze dryers cannot be understated in the modern bubble hash process. Freeze drying is crucial to cannabis producers as well as companies in food, pharmaceuticals, and many other industries. Freeze drying products give companies immense benefits, including longer shelf life and versatility for products. Air drying, which was the traditional way bubble hash has been dried in the past, is a semi-slow process that is not ideal for companies, especially bubble hash and ice water hash producers.

As such, some choose to shorten the process. While this modification often produces positive results, it is not precisely freeze drying, leaving producers stuck between two effective, yet often mistaken, methods.

The main difference between vacuum drying and freeze-drying is that vacuum drying eliminates the freezing stage, which can result in compromised product quality.

What is Freeze Drying?

Freeze drying, or lyophilization, is a process which removes water from perishable materials through freezing. In the case with cannabis, a freeze dryer is a crucial element to making a dry ice water hash or bubble hash.

Inside the freeze dryer, the material is first frozen. From there, the pressure reduces inside the dryer while heat is gently added. The heat allows for the frozen water in the source material to go from a solid to a gas without having become a liquid. This process is called sublimation. From there, it follows an additional drying.

Overall, traditionally freeze drying is a three-step process:

  1. Freezing: Considered the most important step by many, the material is frozen below its triple point, or the temperature and pressure where the sublimation curve, fusion curve and the vaporization curve intersect.
  2. Primary Drying: The sublimation phase which lowers the pressure while adding heat inside the freeze dryer. This step can take a good deal of time as it removes the vast majority of the water in the material is removed.
  3. Secondary Drying: Referred to as the adsorption phase, this is where water molecules are removed from the material.

While effective, a full freeze dry cycle on pharmaceutical-grade lab equipment usually is a two- to three-day process. Its slow process leaves some producers turning to shorter freeze drying methods, sometimes totaling less than a day. While it may seem like this is suitable, some believe that this is actually closer to vacuum drying.

What is Vacuum Drying?

Time is of the essence when producing ice water hash or bubble hash. Thus, the vacuum dry process tends to be a preferred option for many companies, even if they consider it freeze drying.

Vacuum drying is a process that reduces pressure, which lowers the heat in the machine. These steps allow for the material to dry at a much faster pace than a proper freeze drying process typically takes. The process enables producers to speed up their production process while conserving energy. In theory, the method allows a company to cut down on energy costs and turnaround times on products - allowing them to save on costs and earn more revenue overall.

Like freeze drying, vacuum drying is a three-step process that includes a freezing phase followed by a sublimation step and then a secondary drying phase. Virtually all Harvest Right freeze dryers dry via vacuum drying, not freeze drying. 

Consider This…

Dry hash production is a process that is still very much being figured out. Many continue to discover more about the methods and the tech used to achieve its results. With the technology in its infancy, we expect that this learning process should continue for some time until we fully understand the process and its ideal methods. In the meantime, producers need to know the best practices for their business and adapt when the time comes.

So, while producers can potentially get better results by extending their dry times, others will insist that the one-day or less process is suitable for bubble hash and ice water hash production. Some even dry their hash in as little as 8 hours using some of the more advanced units on the market, such as the Labconco FDry-8L.

What’s your preferred method and how do you go about it? Let us know. We’d love to hear from you!