Best Ways to Dry Bubble Hash

The Press Club Freeze Dryer Bubble Hash

Viviane Schute       

Cannabis enthusiast and student of the art of solventless extraction

 ✅ Updated 1/13/21

When pressing rosin, ensuring the ideal moisture content in our starting material is pivotal to the quality and yield of solventless cannabis extract. We know that in the case of pressing flower, a raw flower plucked from a live plant is unworkable between the plates. The popping and hissing of moisture as it rapidly escapes the wet bud is a clear signal that conditions are unfit to extract rosin (and never to be repeated!). 

Just as drying cannabis flowers for rosin extraction is essential, so is properly drying bubble hash for the same purpose. We wouldn’t have any better luck with a wet hash pancake at the press than we do with raw live flowers.

But unlike the cannabis flowers themselves, which can easily be dried in a cool, dark room with some air flow, hash requires a bit more deliberation and prep work to properly dry.

So what are the best ways to dry bubble hash?




There are three main methods that extractors use to dry their ice water bubble hash:

  • Air Drying Method
  • Cold Room
  • Freeze Dryer

The first method, breaking down the wet hash and letting it air dry, is often best for in-home, small scale enthusiasts. The two others, Cold Room Drying and Freeze Drying, are better suited for commercial operations.  

Air Drying


The air drying method involves spreading out the hash in a thin layer over a wide surface area, allowing water to evaporate thoroughly and efficiently via natural air exchange. A cool working environment and cold equipment are helpful. 



Things you need for air drying include:

  • A large piece of cardboard (pizza boxes work great!)
  • Either a microplane or sieve/strainer. We recommend using a sieve
  • Parchment Paper 
  • A freezer 
  • A cool and dark room with low humidity
  • Wet ice water bubble hash 

Step 1: 

Right after collecting the freshly-extracted hash from the bubble bags filters, place the wet hash on parchment paper or slick pads and directly into the freezer. Also place your microplane or strainer into the freezer. Let the hash freeze for 12 hours.

Step 2:  

While the wet hash is freezing you can prep the cardboard or pizza box. Cut sections from a roll of parchment paper large enough to line the bottom of your cardboard, and make sure it's silicone-side facing up.

You can pick up our premium quality parchment here.

Step 3: 

Remove the hash from the freezer. It will be frozen into solid clumps, making it easier to handle. Take one puck-like clump at a time and pass it over the microplane or strainer, using the minimal amount of force required to finely break apart the frozen mass. The goal is to achieve the most sand-like consistency possible, which increases overall surface area of the hash. 

A sieve is a small, bowl-like screen commonly used in cooking and baking but also works very effectively in breaking apart fresh hash to dry. It's also less abrasive than a microplane on the delicate trichome heads. 

Hold the frozen hash pieces between your fingers and scrape back and forth in quick, short strokes across the sieve, applying just enough pressure to push the hash through the sieve and into fine pieces. A spoon can be helpful in pressing the frozen chunks against the screen material, breaking down the hash clump and isolating individual trichomes as much as possible. Just remember to keep everything as cold as possible!

Increasing surface area is the name of the game, as this helps the hash dry more quickly and thoroughly.  It also allows the dry cardboard to more effectively help wick away moisture from the wet hash.

Step 4: 

Close the lid of the pizza box and move to a cool, dark, and dry room. Target temperatures around 55 degrees Fahrenheit and 35% relative humidity if possible. The hash can take from 2 to 10 days to dry. Check the hash for a dry, sandy texture that doesn't leave moisture when squeezed between the fingers. Good hash may be sticky but not damp. 




Cold Room Method 

The Cold Room Method is a modified version of the Air Drying Method, except instead of targeting cooler room temperatures, we create a room that maintains temperatures around 40 degrees Fahrenheit. The ice water hash can be left on top of trays lined with parchment inside the cold room until dry. 

Humidity also needs to be controlled, and using an automated system is an advantage here. Due to the operational complexities of creating a room that sustains these low temps, this setup tends to be better suited for commercial applications. 

The advantage of these cold temperatures is that it reduces the rate of terpene and cannabinoid degradation which happens with exposure to heat. 

One way to achieve the advantages of cold room drying is to use a wine cooler for drying. Wine coolers let us achieve the temperature and humidity needed for drying bubble hash and can fit in a small space. 

For air drying bubble hash, the ideal environment is 35% relative humidity at 55 degrees Fahrenheit. 

The Press Club Best Ways to Dry Bubble Hash

 Freeze Dryer Method

No method does a better job of maintaining the integrity of your trichomes than the Freeze Dryer Method for drying bubble hash. Freeze dryers are specialized pieces of equipment and their price tag reflects such. Cost is the largest downside of using a freeze dryer.  


Depending on your needs, the cost may be completely justified, as freeze dryers allow you to unlock a level of quality in your final product that the other drying methods can’t match. 

Freeze dryers, once purchased and set up, are incredibly easy to use. The magic happens with the push of a button, meaning you can add convenience to the list of benefits with this method. 

Freeze dryers utilize the process of sublimation to remove moisture from wet bubble hash. Freeze dryers don’t rely on natural air exchange to evaporate water, therefore the grinding and breaking-down of fresh wet hash before drying isn’t necessary. Freshly extracted hash can go directly from the ice water filter bags and into the freeze dryer. 

We can better protect the delicate trichome membranes that surround all our desirable cannabis compounds by skipping the microplaning or sieving process. The objective is to avoid bursting trichomes as much as possible throughout the hash making and drying process, and freeze dryers give us a leading edge in this regard. 




Preparation for freeze drying involves simply spreading the wet hash into a very thin and even layer over a parchment paper-lined tray. Then, we need to think about three variables before placing the hash in the freeze dryer: freezer time, drying time, and shelf temperature.

Freeze dryers have settings that enable you to make adjustments to the environment during the drying process. One full cycle of the freeze dryer involves an initial freezing phase, followed by the main drying phase, and lastly a final drying phase. 

The amount of hash you’re drying as well as the overall nature of the hash in its wet form (whether oily or more like sand) will determine the length of your drying time. More unstable and globular/oily hash needs lower temps and longer drying time to dry properly, around 16 hours. Dryer and more stable/sandy hash can take higher heat and shorter drying times around 10 hours. 

Before beginning the freeze drying cycle, make sure the shelf temperature is set to no higher than 50 degrees Fahrenheit, otherwise we increase terpene loss during the process. 

Once the hash seems dry, give it a dab test and listen for popping and crackling. If it’s still wet the moisture will flare out and sizzle in the banger, letting you know that the hash needs more time to dry. 

Learn more in our article How Does a Freeze Dryer Work?



If you have access to a freeze dryer and top quality is your primary pursuit, the freeze drying method is your answer. The use of freeze dryers is becoming standard in the industry and it’s no question they provide a superior drying environment for bubble hash. 

That said, there’s nothing wrong with our trusty Air Drying Method and it’s still a great option for drying bubble hash. If you’re following the correct process you can still attain remarkable levels of quality. 

What’s your go-to bubble hash drying method? Let us know in the comments!

Thoughts? Let us know by joining our secret Facebook group. Hang out with a community of like-minded solventless heads like yourself. Ask our head extractor questions, share your latest press and learn from hobbyists and experts in the industry.



What happens if you don't properly dry bubble hash?
If you fail to properly dry wet hash you invite mold growth which will ruin the hash. It's easy for mold to grow in wet hash and moldy hash needs to be thrown away. 

Can you press rosin with wet bubble hash?
No, there's too much moisture in wet hash for rosin extraction. Bubble hash needs to be thoroughly dried before pressing into hash rosin. 

How can you tell when hash it dry?
Take some hash and rub it between your fingers, then squeeze it into a small and flat pancake shape. There's shouldn't be any moisture oozing out. When it's dry it will resemble a sand-like texture and it won't leave any moisture on your skin. 

How long does it take to dry bubble hash?
It depends on the method used for drying. A freeze dryer takes only 24 hours to dry hash, whereas air drying and cold room methods generally take a week or more. Higher humidity when air drying or cold room drying extends the dry time, while low humidity lessens it. 

What is the best way to dry bubble hash?
Freeze drying hash is the ideal way to dry bubble hash, as it preserves color by minimizing oxidation and maintains the terpene content of the hash. It also saves time and eliminates the risk of mold growth in the hash. 

The Press Club Rosin Starter Guide



After you shred up your hash and it’s asandy like texture and it’s finally dry .How can you get it back into a solid piece form


Can you decarboxilate the bubble hash straight after washing ie while it is still wet? And then press for rosin to make vape juice?

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