Before we get down to the brass tacks of freeze drying weed, it’s important to know that freeze-drying is not the same as putting your buds in a freezer. Freeze-drying cannabis is a more effective way of long-term storage as opposed to freezing cannabis. It ensures a longer shelf-life for your buds while also keeping them potent. The difference lies in what freeze drying avoids that freezing doesn’t.
Reasons not to freeze weed
Freezer burn occurs when cold and dry air in the freezer draws out the moisture in your fresh buds and replaces it with oxygen. While this has the potential to dry your nugs, the moisture has no means to evaporate, so it remains on the surface, where it forms a layer of frost. While it won’t result in your buds becoming susceptible to mold, the freezer burn alone causes reduced potency as it exposes your buds to more oxygen.
Additionally, thawing out your buds after they’ve been frozen leaves them moist and mushy. This is the result of the water molecules in the buds contracting and expanding as it freezes, which destroys the cells’ structural integrity. If you use a normal kitchen freezer, your buds won’t be consumable anymore. And you can only convert them into extracts if you’ve made the proper preparations to catch the fallen trichomes.
Loss of trichomes
Freezing temperatures will result in the trichomes on your buds turning brittle enough to fall off if you touch them. This isn’t ideal if the buds you stored were meant to be smoked. But it can be a blessing in disguise as you can turn the kief into extracts.
Due to the moisture that has collected on the surface of the buds (aka water activity), it will take longer for them to decarb. While this isn’t an issue if you’re smoking them, it can prove detrimental if the buds were meant for edibles. Slower decarboxylation means it needs to stay in the oven longer, which lowers potency as the THC degrades into CBN(1).
What is freeze drying?
As the name suggests, freeze drying is a process that involves freezing the moisture in your buds and drying them. The drying part is achieved through a process called sublimation. Sublimation is a type of transition that turns a solid into its gas state without needing to turn it into a liquid. In our case, it’s the moisture-turned ice crystals in the buds that need to be sublimated into water vapor. And for sublimation to occur, it needs certain temperatures and pressures. This is why freeze drying weed can’t be done with your standard kitchen freezer. You need specialized equipment that has those specific functions.
It’s said that freeze drying is a high-quality dehydration method as it retains many of the flavors of foods, and for the most part, it translates well into cannabis. A little too well, in fact. Studies have shown that freeze drying doesn’t break down chlorophyll the same way standard drying methods do(2)(3). It’s for this reason, we recommend that if you freeze dry cannabis, do so with the intention of using it for making hash.
How does freeze-drying cannabis work?
There are three stages in freeze drying(4). The first is deep freezing which is the stage where you bring the buds down to -40°C (-40°F) or lower. This is done to turn the moisture in your buds into ice.
The second stage of the process involves sublimating the ice into water vapor. This is done by lowering the pressure in the freeze dryer. One thing to note is that this is all done automatically.
The last step, also known as the secondary or final drying, is when your freeze-dried weed is brought back to room temperature. This removes the last bit of moisture from the buds.
What are the benefits of freeze-drying marijuana?
The main benefit of freeze drying weed is that it improves certain qualities, such as flavor and shelf life.
But that’s not all. A study states that the best method for drying buds is freeze-drying. It preserves the quality and does so for longer than traditionally cured weed(4).
Freeze drying as a method for curing
One of the more novel ways of curing cannabis is through a freeze dryer. Unlike traditional drying methods that implement heat, freeze drying does the opposite. It uses extremely low temperatures to dry and cure your buds. The resulting end-product has a higher quality to it and a longer shelf-life. However, freeze-drying isn’t necessary for the home grower.
It’s more of a nice-to-have sort of thing rather than a necessary piece of equipment. And while it does make for a higher quality product, at the end of the day, it’s still a matter of preference. So only invest in a freezer dryer if you’re keen to try your hand at modern, high-quality hash making.
Why freeze-drying cannabis for extraction is important
I’m sure the term ‘fresh frozen’ somewhat rings a bell, and you may have seen it being thrown around in articles covering freeze drying. This is because fresh frozen is a term used to describe a method that growers use to preserve the quality of their buds to turn them into high-quality extracts.
Freeze drying is key to this process since the trichomes of freeze-dried cannabis fall off a lot easier, unlike traditionally dried and cured ones. This is ideal when putting it through an ice water bath to make bubble hash which can then be pressed into live rosin.
What to look for in a freeze dryer for cannabis
When looking for a cannabis freeze dryer, the main things you need to consider are price, capacity, and rating. With price, there’s the cost of the freeze dryer itself and the ongoing costs. Overall, you might be looking at an average of $2,500 to $5,000 (depending on the size and type of pump) with a $30 to $50 ongoing cost to run it. For its capacity, it should have a shelf area of 1 square meter and a condensing capacity of 30 liters.
How do you freeze dry properly?
Freeze drying marijuana requires you to use a professional freeze-dryer. This is because, with the right appliance, you won’t really need to do much of anything as the machine does everything for you. It beats working with something potentially hazardous as dry ice, which, in poorly-ventilated areas, can result in a buildup of carbon dioxide.
When should you put weed in the freezer?
When preparing live resin
The only acceptable reason for putting your weed in the freezer is if you plan to make high-quality extracts out of it. By putting your buds in the freezer dryer, it’s left preserved and prepped until ready to be made into either solventless or solvent extracts (aka ‘Dabs’).
The solvent extraction process involves using the (fresh) frozen buds and subjecting them to a solvent such as propane or butane to extract the resin. From there, the extract is purged, leaving behind a rich concentrate of cannabinoids and terpenes. It’s important to note that, like freeze drying, this process involves specialized equipment. Moreover, the compounds involved are volatile and dangerous, which is why we advise against making resin using these gasses.
When making ice hash
Ice hash (ice-o-later) or bubble hash is a method of making a more refined form of hash. It doesn’t strictly need you to use frozen buds; if anything, you can also just use dried and cured cannabis to make it. But there’s a notable difference in flavor and fragrance if you use (freshly) frozen or freeze-dried buds because of how well they’ve preserved the terpenes in the trichomes.
As for the process of making bubble hash, you won’t need any chemicals. Instead, you prep your frozen or freeze-dried buds for an ice wash where they’ll be stirred. This part of the process will break off the trichomes from the flowers, making it much easier if frozen or freeze-dried. Once they’re broken off, the resulting kief is then dried for 2 to 10 days, wherein it will become translucent.
Freeze drying is a novel way to dry and preserve your buds. It has the advantage of traditional drying methods in that it preserves the flavors and potency of your herbs. Yet, it is a specialized field and might not be obtainable or even necessary for most novice growers. If you do think this is something for you and you want to try your hand at freeze-drying cannabis, you need to grow weed that’s worth freeze drying in the first place. Buy seeds at ILGM.
FAQs About Freeze Drying Weed
How long does freeze drying weed take
Most freeze dryers nowadays only take a day or so to complete the process (20 to 40 hours). The time it takes does depend on the quantity you put in as well as the amount of moisture in your buds.
Does putting weed in the freezer make it less potent
Not necessarily. The only reason people say putting weed in a freezer makes it less potent is because of how the trichomes on the flowers will break off. In reality, freezing your buds preserves their potency and flavor much better than drying and curing. But it has the downside of only making your frozen buds viable for hash making instead of smoking.
What temperature do you freeze dry weed at
-40°C (-40°F) or lower, and it’s important that it’s done immediately. By flash-freezing your buds, you prevent ice crystals from forming, which would otherwise ruin their quality. This is also the main reason why your kitchen freezer is not up to the task of preserving and curing your precious bud to perfection.
- Russo E., Marcu J. Advances in Pharmacology. https://www.sciencedirect.com/topics/nursing-and-health-professions/cannabinol
- King V., Liu C.F., Liu Y.J. Chlorophyll stability in spinach dehydrated by freeze-drying and controlled low-temperature vacuum dehydration. https://www.sciencedirect.com/science/article/abs/pii/S0963996900001484
- Roshanak S., Rahimmalek M., Goli S.A.H., Evaluation of seven different drying treatments in respect to total flavonoid, phenolic, vitamin C content, chlorophyll, antioxidant activity and color of green tea (Camellia sinensis or C. assamica) leaves. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4711456/
- Nikas S., Wills R., Chandrapala J., Post-Harvest Operations to Generate High-Quality Medicinal Cannabis Products: A Systemic Review. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8911901/