Hang-Dried vs Freeze-Dried Cannabis
For flower you are going to smoke, buy hang-dried. Ten to fourteen days hanging near 60°F and 60 percent humidity gives chlorophyll time to break down, and that slow breakdown is what makes the smoke smooth. Freeze-dried flower, often sold as cryo cured, keeps more of its brightest top notes and is finished in about two days, but it smokes crisp and green; freeze-drying earns its place on ice water hash, where nothing beats it.
By Eleanore Editorial, editors of the eleanore guides to cannabis craft · Published
Walk into an old Humboldt drying barn in late October and the first thing you notice is the dark. The second is the smell, which hits about four steps in and does not let go. Whole plants hang upside down from wires strung between the rafters, the way tobacco has hung in Kentucky barns since before the Civil War. For the next two weeks the only job anyone has is to hold the room cool and dark, and then to leave the plants alone.
That is the old way. A freezer with a vacuum pump is the new one.
Freeze-dried flower started turning up on dispensary menus over the last couple of years, usually with the word cryo somewhere on the label and a claim about “locking in” terpenes. The claim is partly true. We have smoked enough of it, side by side with hang-dried jars of the same cultivar, to have an opinion, and the opinion is that the machine solves a grower’s problem much better than it solves a smoker’s.
What a slow dry is doing
A freshly cut plant is roughly three quarters water. In a hang dry that water leaves from the inside out: it travels up through the stems and out through the flower, so the surface of the bud never gets ahead of the core. Meanwhile the plant is still, in a slow and fading way, alive. Enzymes go on working for days after the cut, chlorophyll breaks down, and the green, grassy edge that makes fresh-cut cannabis taste like a lawn starts to recede. Craft growers call the target conditions the 60/60 rule, 60°F and 60 percent relative humidity, and they hold it for ten to fourteen days before anything goes into a jar.
Our guide to what makes cannabis craft covers why a hot, fast dry ruins flower. This page is about the newer argument, which is whether skipping the slow dry entirely, with a machine, is the improvement it is sold as.
What a freeze dryer is doing
A freeze dryer drops the flower well below freezing and then pulls a vacuum. Under that low pressure the ice in the plant turns straight to vapour (sublimation, the same thing that slowly shrinks ice cubes left in a freezer for a month) and is pulled out of the chamber before it ever becomes liquid. Most of a cycle runs cold, far below the temperatures at which the lightest terpenes boil off, and it is done in a day or two.
The benefits are real. The monoterpenes behind citrus and pine top notes, the first to leave in any warm room, stay in the bud. Color stays vivid. There is no window of several days where damp flower hangs in a room that could tip toward mould, which matters a great deal to a grower on the foggy North Coast who has lost a season to it.
What the machine cannot do is wait. Because the plant goes from living tissue to frozen in hours, the slow enzymatic work that clears chlorophyll mostly does not happen. In our experience the smoke from freeze-dried flower is loud on the first draw and then thin and faintly green. And the buds are brittle. Put one in a grinder and it shatters into dust and fine crumbs instead of fluffy pieces, which burns fast and hot in a joint.
The drying methods compared
Producers rarely print how flower was dried, so the table below is our reading of each method from the buyer’s side of the counter. Times are typical ranges, and a careful operator can beat them in either direction.
| Method | Typical time | What it keeps | Cost to the grower | Best for | Key trade-off |
|---|---|---|---|---|---|
| Whole-plant hang dry | 10 to 14 days near 60°F and 60% RH | Most aroma of any slow dry; chlorophyll breaks down fully | Most room space and labour per pound | Flower you will smoke or vaporize | Mould risk if the room drifts warm and wet |
| Branch hang dry | 7 to 12 days | Close to whole-plant if the room is right | Less space; branches cut before hanging | Most craft indoor and greenhouse flower | Smaller branches finish faster and can overdry at the tips |
| Rack or screen dry (bucked buds) | 5 to 10 days | Fair; buds lose water from every side at once | Cheap to stack, easy to scale | Large harvests, smalls, pre-roll material | Outside of the bud dries ahead of the core |
| Forced-air fast dry | 3 to 5 days, often above 70°F | Least of any method; top notes leave with the heat | Lowest cost per pound and fastest turnover | Price-led shelves and extraction biomass | Harsh, flat smoke even after a cure |
| Freeze-dried flower (sold as “cryo cured”) | About 24 to 48 hours under vacuum | Bright monoterpenes; color and bud shape | Expensive machines, small batches per cycle | Humid climates, vaporizer users, flower that would otherwise mould | Crisp, brittle buds; chlorophyll never gets the slow breakdown |
| Freeze-dried ice water hash | About 24 to 48 hours under vacuum | Nearly the whole aroma of the fresh-frozen plant | Same machines, far less material per run | Bubble hash and solventless rosin | None worth the name. This is what the machine is for. |
Where freeze-drying wins outright
Hash. When a solventless maker washes fresh-frozen plants in ice water, what comes out of the micron bags is a wet paste of trichome heads, the most fragrant and most fragile material on the plant, and it has to be dried fast and cold or it will either mould or go flat. Freeze-drying is the answer almost every serious hash room has settled on. There is no chlorophyll to break down, because the leaf stayed behind in the wash water. Our guides to solventless rosin and live resin vs live rosin follow that hash on to the press.
So the machine is good. It has simply been pointed at the wrong thing.
How to tell which one you are holding
Most labels will not tell you. The jar usually will. Freeze-dried buds tend to look slightly inflated and keep a bright, almost fresh green, with trichomes that look glassy and intact. Pick one up and it feels light for its size and crisp at the surface, with none of the gentle spring of a well-cured bud. A hang-dried bud is denser in the hand, a little darker, and the stem snaps cleanly. Smell tells you the rest. Freeze-dried flower opens with a big burst of top note and then fades quickly, while hang-dried flower that was cured with patience keeps repeating its smell after the lid has been closed for half a minute, the test we describe in how to tell if cannabis is properly cured.
If the grinder turns it to dust, you have your answer.
Where each method fits (and where it does not)
Whole-plant and branch hang drying fit any flower you mean to burn or vaporize, and they are what we look for first. They do not fit a wet coastal harvest in a bad year, where a grower without climate control can lose the whole room to botrytis waiting for it to dry. There, a freeze dryer is the responsible choice, and we would rather smoke crisp flower than mouldy flower.
Freeze-dried flower fits vaporizer users who run low temperatures and mostly want the top notes; at 350°F or so, on the settings in our vaporizer temperature guide, the missing chlorophyll breakdown matters much less than it does in a flame. It is a poor fit for joints and pre-rolls, because brittle, finely ground flower packs unevenly and burns hot. Forced-air fast drying fits extraction biomass and very little else.
Pre-rolls deserve a separate word, because you cannot see the bud. A ground pre-roll hides the dry completely, so the only way to know is to ask the producer, and that applies to us as well. Our own Parlor Smokes in The Parlor are sun-grown flower blended with botanicals like rose petal, lavender and chamomile at about 2.5 percent THC, and if you want to know anything about a batch, write to hello@deareleanore.com and ask. A producer who will not tell you how a pre-roll was made has told you something too. For what to check in any pre-roll, ours or anyone else’s, read how to judge a pre-roll.
Our position
A freeze dryer saves a grower ten days of risk and rent. Nothing about that is dishonest, and in humid places it saves whole harvests. But the case for buying freeze-dried flower usually rests on a lab figure (more total terpenes on the certificate) and the aroma when the jar opens, and neither of those is the same thing as the smoke. We would like to see the drying method printed on every label next to the harvest date, so buyers can learn the difference for themselves. Until then, squeeze a bud before you pay, and buy the hang-dried jar for anything you plan to light.
Frequently asked questions
Is hang-dried or freeze-dried cannabis better?
For flower you plan to smoke, hang-dried is better. A slow hang dry of ten to fourteen days near 60°F and 60 percent humidity lets chlorophyll break down, which is where smooth smoke comes from. Freeze-dried flower keeps more of its brightest top notes but smokes crisp and green. For ice water hash, freeze-drying is the better method by a wide margin.
What is freeze-dried or cryo cured cannabis?
Flower that has been frozen and then dried in a vacuum chamber, where the ice turns straight to vapour without passing through liquid. A cycle takes roughly one to two days instead of the one to two weeks of a hang dry. Some producers sell it as cryo cured, though no cure in the traditional sense takes place.
How can you tell if cannabis was freeze-dried?
The buds look slightly puffed and keep a vivid, almost fresh green. They feel crisp and light for their size, and they shatter in the grinder instead of breaking into fluffy pieces. The smell is loud at the top and thin underneath. If the label does not say, ask the shop.
What is the 60/60 rule for drying cannabis?
A shorthand among craft growers for drying at about 60°F and 60 percent relative humidity, usually for ten to fourteen days, in the dark with gentle air movement. Cool and slow keeps volatile terpenes in the flower while the stems release water gradually.
Why is ice water hash freeze-dried?
Washed hash comes out of the bags soaking wet, and it is mostly trichome heads, the most volatile part of the plant. Air-drying wet hash risks both mould and lost aroma. Freeze-drying removes the water in a day or two at temperatures far below where terpenes evaporate, which is why most serious solventless makers use it.