How To Prepare Fresh Frozen Cannabis and Average Yield for Washing Bubble Hash

THE PRESS CLUB HOW TO PREPARE FRESH FROZEN CANNABIS
THE PRESS CLUB TIPS AND TRICKS VIVIANE
Viviane Schute        

Cannabis enthusiast and student of the art of solventless extraction

 

 

Fresh frozen cannabis is a type of starting material used in the ice water extraction method of creating bubble hash. The difference between fresh frozen and other types of cannabis material, such as dried and cured flowers, is in the specific treatment of the material after harvest. Fresh frozen cannabis is grown in the same way as cannabis destined to be air cured in the traditional fashion, but rather than hung to dry, fresh frozen cannabis is harvested and then immediately frozen at subzero temperatures. 

Fresh frozen cannabis as a starting material for bubble hash production offers benefits for both extractors and consumers. While air dried flower and trichome-rich trim leaf has been a time-tested source of premium hash, the trend toward fresh frozen cannabis is more than just a passing fad. The results that extractors can achieve with fresh frozen material speak for themselves. 

Benefits of Fresh Frozen Cannabis as Starting Material for Bubble Hash Production

The main benefit of using fresh frozen cannabis in the production of solventless hash is preservation. Specifically, preservation of the profuse amount of terpenes and flavonoids that exist in the cannabis plant while it’s alive. Harvested plants quickly deteriorate, and these valuable terpenes are lost as the plant’s metabolism halts and compounds within the trichomes begin to oxidize and degrade. Air drying can lead to around 40% loss of terpene content. However, terpene degradation is slowed significantly in freezing temperatures, which means that fresh frozen material maintains the essence of the live plant extremely well. 

Freeze drying in air-tight packages also drastically slows the process of oxidation, which is responsible for a darkening of trichomes. While color isn’t the leading indicator of quality, consumers generally look to lighter color as an important signal of a premium product. Freeze dried trichomes maintain their lighter color while air dried trichomes will oxidize and darken noticeably with exposure to air. 

Fresh frozen preparation eliminates the need for a drying room and the environmental controls that go with it, another advantage over the air drying preparation. 

Another benefit of fresh frozen cannabis for extractors is the increased flexibility in production schedules. Fresh frozen preparation increases the shelf life of cannabis flowers so they remain of the highest quality prior to hash extraction. Once cannabis is freshly frozen, extractors can begin processing right away, or wait several weeks or months before extraction. Fresh frozen eliminates the need to rush cannabis through an extraction process in order to take advantage of an exact window of optimum freshness, as is the case with air dried buds. With a lot of material on hand, this flexibility is key.  

 

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Alongside the increased flexibility and shelf life, fresh frozen gives extractors a savings in labor and time, wiping out the multiple steps and manual work that’s required of the hang drying process. 

Finally, freezing temperatures prevent microbial growth such as mold. Mold and mildew growth is a major environmental concern when air drying cannabis flowers, but this isn’t a concern inside of a freezer. Although a freezer won’t eliminate microbes that existed at the time of harvest, it will prevent new growth. If you’re starting with clean, microbial-free cannabis, you can rest assured that mold growth won’t sneak up and destroy your fresh frozen product while it’s in the freezer. 

Equipment Needed To Prepare Fresh Frozen Material

 

Industrial Freezer
While ordinary residential freezers and chest freezers do a fine job of freezing food (and can technically freeze cannabis as well), these aren’t up to snuff for fresh frozen cannabis. Industrial freezers capable of reaching subzero temperatures are best suited for fresh frozen cannabis. The freezer should be capable of reaching at least -4 degrees Fahrenheit. 

THE PRESS CLUB HOW TO PREPARE FRESH FROZEN CANNABIS

 

Vacuum Sealer Machine
Standard vacuum sealing machines work with most types of plastic bags used for packaging fresh frozen cannabis. The best machines to use for cannabis will have a few different sealing options (various levels of suction power), which will be helpful to avoid overly compressing the flowers inside the bag. 

Plastic Bags
Turkey bags have been a staple in the cannabis industry for packaging pounds of dried flower, but they’re not the best option for holding fresh frozen material. The thin plastic of turkey bags can still allow oxygen and moisture to pass through, which can diminish the quality of the product inside. Thick plastic vacuum bags that hold 2-4 pounds, also called plastic pillows, are the best bet for fresh frozen.

Cannabis Trimming Scissors
Nothing out of the ordinary here, just be sure to source high quality, comfortable trimming scissors that are up for the job.


How To Prepare Fresh Frozen Cannabis

Determining your crop’s ideal ripeness is the first step to prepare the best fresh frozen cannabis material. We wrote an article to help you harvest at just the right time. Check out How To Harvest Cannabis for Peak Trichome Ripeness. Once harvest day finally arrives, follow this basic process:

  1. Remove fan leaves with your trimming scissors while the plants are still in their pots. Discard these leaves. Material that isn’t visibly covered in trichomes won’t be useful for extraction.
  2. Remove all branches containing flowers and place them into bins. Main branches should remain intact during the initial chopping phase. Metabolite loss is increased if the plant is rapidly chopped into small sections before the flowers are removed. 
  3. Break larger flowers into smaller chunks so that unnecessary stems can be removed. The goal is to minimize stems but not completely eliminate them.
  4. Once the buds are broken into medium-sized chunks, it’s time to place them into bags. Use bags that are large enough to hold anywhere from 2-4 pounds of product.  
  5. Vacuum seal the plastic bags, careful not to overly compact the buds and damage trichomes. Adjust the setting on your vacuum sealing machine so that moderate suction power is used. 
  6. Adjust the settings on the freezer for subzero temperatures, the ideal range being between -4 to -38 degrees F. 
  7. Move the vacuum sealed material into the freezer as quickly as possible. Terpenes evaporate quickly in the open air after harvest. The sooner the flowers get into the freezer, the better. Flowers should be frozen within one hour of being harvested.

Once the flowers are frozen, be sure to keep them frozen until the extraction begins. 


How Long Can You Keep Fresh Frozen Cannabis? 

THE PRESS CLUB HOW TO PREPARE FRESH FROZEN CANNABIS

 

Cannabis frozen at subzero temperatures has an impressive shelf life. There’s no need to rush into processing. Part of the beauty of fresh frozen is the freedom and flexibility that it gives extractors to create solventless concentrates based on demand, rather than adjusting production schedules based on a limited window of source material freshness. 


Fresh frozen material will retain its vitality for several months while stored in air-tight plastic bags inside an industrial freezer.  

Red Flags and Things To Avoid 

Squeezing the flowers too tightly together while vacuum sealing is the most common downfall of the fresh frozen process. The buds will naturally become pressed together to some extent as air is pulled from inside the plastic covers, but if the compression is too aggressive, delicate trichomes will rupture. These damaged trichomes then release the valuable resin contained therein, which means it won’t be collected during the ice water extraction process. When vacuum sealing your flowers inside the bags, use every precaution not to damage trichomes with an overzealous approach.  

 

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Exposure to oxygen leads to freezer burn, which is a sure sign of degradation. It’s important to keep your product in an air-tight environment. Any punctures in the plastic bags will invite oxidation and diminish the quality of your material. 

Another detriment to your fresh frozen material is shaking the bags or handling them with indifference to the delicate nature of the trichomes. Trichomes frozen to very low temps become brittle and easily fall off. The goal is to keep all trichomes intact and attached to the material until the ice water extraction process begins. 

Lastly, power outages can be a nightmare for many different aspects of the cannabis producers’ process, and the fresh frozen realm is no exception. It’s detrimental to the material to freeze and then thaw. Once the cannabis is frozen it should stay frozen, so having backup generators on hand is a good safety net to have in place. This is especially true in California where planned lapses in power supply are to be expected, especially during wildfire fire season.  

Average Yields

When it comes to hash yield as a percentage of total weight of your starting material, there is a significant difference between dry material and fresh frozen material. The amount of moisture in fresh frozen  is much higher than the moisture in dried cannabis, which accounts for the variation in yield percentages between the two types of starting material. 

For Dried, Air-Cured Cannabis, 15-20% yield is a good target. For fresh frozen, look for 3-8%. The rule of thumb for calculating wet (fresh frozen) weight to dry (air cured) weight is 5:1. So if you get 4% wet, that’s equivalent to 20% dry.

Conclusion

Fresh frozen is the way to go if your goal is to produce the most terpene-rich hash and rosin possible. Although there are extra expenses involved, the outcome makes it all worth it. 

Another thing to keep in mind when washing fresh frozen material is the risk of ice nucleation leading to chlorophyll contamination in your water and then into your hash. The key is to keep the material as close to frozen as possible for the duration of the extraction. Learn more about Ice Nucleation and how to minimize contamination in What Is Ice Nucleation in Fresh Frozen Cannabis?


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FREQUENTLY ASKED QUESTIONS


How long can you keep fresh frozen material?
Fresh frozen cannabis has a long shelf life, several months or even a year or more. 

What temperature should you keep fresh frozen cannabis?
-4 to -38 degrees Fahrenheit is a good range for fresh frozen cannabis

What causes freezer burn?
The presence of oxygen around the cannabis will lead to freezer burn

How can you prevent freezer burn on fresh frozen cannabis?
Using vacuum sealed bags is the way to prevent freezer burn on fresh frozen cannabis.

Can you use a regular residential freezer for fresh frozen cannabis?
While a residential freezer can help preserve terpenes and slow degradation of the cannabis, they do not reach the ideal temperatures for keeping fresh frozen cannabis. Commercial freezers capable of reaching subzero temperatures are ideal. 

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