Drying bubble hash is the final part of the ice water extraction process—the process by which trichome heads are detached from cannabis plant material using cold water, ice, and agitation.
After collecting the trichome heads in a series of mesh filtration bags (or "bubble bags"), the resulting slurry needs to be dried before you can sell it as bubble hash, roll it into temple balls, or press it to make hash rosin.
You can't leave wet bubble hash as it is because the moisture could lead to mold growth and it would be way too wet to smoke or dab. Once the hash is completely dry, however, you can process it further or send it to the lab to be grammed out and packaged for distribution.
There are two main methods for drying hash: air drying and freeze drying. If you're thinking of making bubble hash commercially or want to make top-quality bubble hash for personal use, it's important to be aware of both of these techniques and the advantages and disadvantages of each.
Air Drying Bubble Hash
Air drying hash is the technique that was originally used when the ice water extraction method was invented. You can get decent results if you can create the ideal environment. To air dry bubble hash once the ice water extraction process is complete, you'll first need to prepare the wet hash and then place it in a suitable environment to dry.
- Scoop the bubble hash directly from the bag to a blotting screen.
- Use the blotting screen and spoon to form the hash into a square shape that is about 1/4 inch thick.
- Place four paper towels under the blotting sheet and flip your square hash patty.
- Freeze the hash overnight until it is a solid block.
- Use a frozen microplane to gently break apart the hash into granular piles over a sheet of parchment paper. Only use a forward motion against the grain of the plane. Don't move back and forth.
- Every three strokes, tap your microplane on the parchment to remove any excess from the bottom.
- Allow it to dry in a 50 degree room with around 35-50% relative humidity and plenty of airflow for 24 hours.
- Collect all of your hash into a pile and run it through a sieve to get rid of any large chunks of hash that have formed. Let it dry for another 24 hours.
- Jar it and store it in a freezer.
Freeze Drying Bubble Hash
The freeze drying process is quicker and easier than the air drying process.
- After making bubble hash, scoop the wet hash onto freeze dryer trays lined with freeze dryer tray liners. Make sure that the hash on each of the trays is of a similar thickness (around 1/8") so that the hash dries evenly. You can tap your trays on any surface to level the hash.
- Freeze the hash in a standard freezer until it is frozen solid.
- Put the trays in a suitable freeze dryer.
- Run a 4-hour freeze cycle to get the chamber frozen solid.
- Run the freeze dry cycle. The freeze dryer will remove the moisture from the wet hash under a vacuum via sublimation. Sublimation occurs when ice evaporates without passing through a liquid phase.
- Jar the dried bubble hash and store it in a freezer.
Air Drying vs Freeze Drying Bubble Hash Pros & Cons
Both methods of drying bubble hash have advantages and disadvantages. The best solution will depend on your budget and goals.
Advantages of the Air Drying Method
- The air drying method doesn't require any special equipment, although you'll need an air conditioner, Coolbot, and humidity control equipment for best results if you don't have a suitable cold room or wine cooler.
Disadvantages of the Air Drying Method
- Air drying takes several days (at a minimum) and often more than a week if you’re in an environment with high humidity.
- The longer dry time means increased terpene loss and greater oxidation. Oxidation turns bubble hash brown (think of the "enzymatic browning" that happens after you slice an apple). A darker color greatly reduces its shelf appeal.
- A slower drying process means there's more opportunity for mold growth in your hash patties.
- Air drying is less precise than freeze drying.
Advantages of the Freeze Drying Method
- A freeze dryer can dry hash in as little as 18-24 hours.
- Freeze dried hash is very light in color, which enhances its shelf appeal and marketability.
- Freeze drying minimizes terpene loss and oxidation.
- The efficiency of freeze drying means there's little to no opportunity for mold growth.
- The freeze dryer protects the hash from external contamination.
- Top-end freeze dryers can be programmed for a high level of precision and control.
Disadvantages of the Freeze Drying Method
- Freeze dryers are costly, making them unfeasible for home extractors and startups with tight budget constraints. For industrial operations, however, a freeze dryer is essential. Freeze drying hash can generate an impressive ROI if your starting materials and extraction process are up to par.
The Best Way to Dry Bubble Hash
If it's quality and consistency you're after, the best way to dry bubble hash is with a freeze dryer—by a mile. If you're a serious extraction business with the ability to invest in equipment, a freeze dryer will enable you to make beautiful sandy-colored bubble hash that's ideal for smoking, dabbing, or pressing for hash rosin.
For beginners and hobbyists, there's nothing wrong with air drying bubble hash. Just make sure you've got the right temperature and humidity in your drying environment. However, if you want something you can market to consumers, invest in a freeze dryer. You won't regret it!