Harvest is done, the buds are hanging, and there is a bag of trim and sugar leaf in the freezer. That trim is the start of bubble hash. Bubble hash, also called ice water hash or water hash, is made by knocking the resin heads off frozen plant material in ice water and catching them in mesh bags. It needs no solvent and no heat, just cold water, a few bags and an afternoon.
This guide covers making bubble hash at home with bags, from picking material to drying and storing the finished hash, for growers washing their own trim for the first few times. It builds on Blaze's step-by-step bubble hash thread, GNick55's bubble washing thread, and about 7,700 posts in which members shared their bags, times and returns. Making hash is legal only where home processing of cannabis is, so check your local laws first.
01 · Quick answer How to make bubble hash
- Freeze your trim or small buds overnight so the resin heads turn brittle.
- Soak the frozen material in ice water for 15 to 30 minutes.
- Stir gently for 5 to 15 minutes to knock the heads loose.
- Pour the slurry through a stack of bubble bags, finest bag at the bottom, and let it settle for about 10 minutes.
- Pull the bags from coarsest to finest and scrape out each grade separately.
- Press out the water, grate the hash and dry it somewhere cold for several days.
- Press it by hand and store it cool and dark.
Expect about 10% of the dry weight of your material back as hash.
02 · Guide What bubble hash is and why it bubbles
The resin on cannabis sits in the heads of the stalked glands, the trichomes that frost buds and sugar leaves. Those heads hold most of the cannabinoids and terpenes. Ice water makes them brittle, stirring snaps them off their stalks, and because they are heavier than water they sink while most of the broken leaf floats. Mesh bags then sort what sinks by size.
Size is why the bags matter. A study of fresh cannabis flowers measured the gland heads at 40 to 110 microns across (Punja and others, Journal of Cannabis Research, 2023). Bags with holes in that range catch whole heads. Finer bags catch broken heads, immature glands and plant dust, and coarser bags let leaf through.
The name comes from the lighter test: clean, dry hash melts and bubbles under a flame. The best grade, called full melt, melts almost completely. Bubbling tells you the hash is clean and dry. It does not tell you how strong it is.
03 · Guide What you need to make bubble hash
Bubble bags
Mesh bags that nest inside each other in a bucket, each one finer than the bag above it. A 4-bag set, usually 220, 160, 73 and 25 microns, is enough to start. Blaze ran an 8-bag set and still wrote that "Good results can be achieved with a 4 bag set." Extra bags give you more grades, not more hash. A 5-gallon set handles up to about 8 ounces of material per wash, a 20-gallon set about 1 to 1.5 pounds.
Two buckets
One to mix in and one to hold the bags. In Blaze's words, "NEVER actually mix in your bags, only use them for straining." Stirring inside the work bag wears the mesh and pushes leaf through it.
Ice and cold water
Roughly equal parts ice and water. Plan on two 7-pound bags of ice for a 5-gallon wash and about 30 pounds for a 20-gallon run, plus more for every extra wash. Keep the water at or below about 40°F (4°C) with ice floating the whole time, because warm resin heads go soft and stay stuck to the leaf. GNick55 prefers RO water and RO ice, but tap water works for a first run.
Something to stir with
A wooden paddle or spoon is the gentlest. A drill with a paint mixer on its lowest speed saves your arms but shreds more leaf. A small washing machine is the easiest for repeat washes and is what GNick55 uses. The gentler the agitation, the less green ends up in the hash.
For collecting and drying
A hose with a gentle spray nozzle or a spray bottle, a spoon or plastic card, a 25 micron pressing screen, parchment paper, a fine rasp grater (members use a microplane), and a scale.
04 · Guide Choosing material for bubble hash
Hash can only be as good as what goes into the bucket. Old, over-dried or brown material, fan leaves, stems and dirt all make poor bubble hash.
Trim and sugar leaf
The small, resin-covered leaves trimmed off buds are the standard material. Leave out fan leaves and stems, which add bulk and green but little resin.
Small buds
Larf and popcorn buds make more and cleaner hash than trim. Break them into small pieces so the water reaches the resin inside. Washing good flower costs a lot of smoke, though: as one member put it in Questions on using buds for bubble hash, "5-6 oz of bud turns to grams of hash."
Fresh frozen or dried
Fresh frozen material goes into the freezer within hours of harvest, with no drying. Members who have tried both mostly prefer it for flavor and melt, though the return looks smaller by weight because the material still holds its water. Dried and cured trim is easier to store, but use it within a few months: Blaze found that shake left an extra 8 months washed with far less flavor and bubble. Trim dried until it crumbles turns to dust that slips through the bags, so give very dry material a longer soak.
Warning: never wash moldy buds
Nobody has shown that bubble bags remove mold or its toxins, and the World Health Organization notes that most mycotoxins are chemically stable and survive food processing. Bin any bud with rot and the buds touching it. Blaze agreed: "Personally I would never make bubble hash out of moldy bud either." See the bud rot guide and what extraction can and cannot do with moldy buds.
05 · Guide How to make bubble hash step by step
These steps use a bucket and a paddle or drill. With a washing machine, the soak and mix happen in the machine. For the same process with photos, see Blaze's original step-by-step.
1. Freeze the material
At least overnight, in sealed bags. Frozen heads snap off cleanly, while soft ones smear and stay on the leaf.
2. Chill the water
Fill the mixing bucket a quarter to a third with water and ice and let it cool for 15 to 20 minutes, so less ice melts during mixing.
3. Stack the bags
Put the finest bag in the empty bucket first and the 220 work bag last, on top. Add cold water until the screens sit under a few inches of it, because a heavy slurry dumped on dry screens strains the seams. Members compare stacking orders in Bubble bag stacking order.
4. Soak
Add the frozen material and more ice to the mixing bucket with enough water for a slushy, stirrable mix, then let it sit 15 to 30 minutes so the resin chills all the way through. GNick55 gives very dry material 30 to 45 minutes and makes the point that "it's not the ice, it's the motion of the cold water that extracts the trichomes."
5. Mix gently
Stir in a smooth circle for 5 to 15 minutes, reversing direction every minute or so. Of 18 members who gave a time, 15 land in that range. Blaze stopped at 5 to 10 minutes after looking closely at washed material: the mature heads were already off, and more stirring only added leaf. With a drill, use the lowest speed.
6. Pour and settle
Pour the slurry slowly into the work bag, rinse the mixing bucket into it, cover it, and let it settle about 10 minutes so the heads sink through the screens. Blaze later cut this to 5 to 8 minutes, because material left sitting longer loses terpenes to the water.
7. Pull the bags
Lift the work bag, let it drain, and tip the plant material into a spare bucket for a second wash. Then lift each bag in turn. Rinse the inside walls with cold water so stuck heads wash down, but never spray straight onto the screen, which forces leaf through it.
8. Collect each grade
Stretch the bag over a bucket, spray the hash toward the center of the screen, and scoop it out with a spoon. Keep every grade on its own labelled dish. You will not know which bag is best until each one dries.
9. Wash again
Put the material back in fresh ice water for a second, shorter wash. Each wash returns less. GNick55 stops when a wash gives about a gram or less, or when the hash turns greenish, which takes 6 to 8 washes for dried buds in a machine. Blaze, mixing by hand, rewashed once and gained 10 to 20%.
10. Clean the bags
Rinse each bag with cold water as soon as it is empty. Hot water melts leftover resin into the mesh, and alcohol damages the screens. More tips in How to clean bubblebags?.
06 · Guide Which bubble bags to keep: A micron guide
When members name their best bag, 19 of 24 pick the 73 or the 90, which fits the gland head sizes above: whole heads collect in the middle bags. One member summed it up in What to do with so much bud: "You'd think the best would be the bag with the smallest holes however it's the mid bag 73u."
| Bag (microns) | What it catches | Keep it? |
|---|---|---|
| 220 | Plant material (work bag) | No: rewash or compost |
| 190 and 160 | Leaf bits, a few very large heads | Rarely |
| 120 | Large heads with some plant matter | Yes, often cooking grade |
| 90 | Whole heads, usually the most hash | Yes, top grade |
| 73 | Whole heads, often the cleanest | Yes, top grade |
| 45 | Smaller and immature heads | Yes, mid grade |
| 25 | Broken heads, stalks and fine dust | Usually cooking grade |
Strain changes the result. A few members find their best hash in the 25 bag, mostly with sativa-leaning plants, and Blaze occasionally had a batch where the 120 or the 25 came out best. Try each grade on its own before you combine any of them. In a 4-bag set, the 73 does the job of both middle bags.
07 · Guide How to dry bubble hash without mold
Fresh bubble hash is wet, and drying is where most batches go wrong. Seal it damp and it molds: one member lost 70 grams that way in mold on my hash. Dry it warm or fast and the terpenes go. This is the method most current members use.
Press out the water
Put each grade on a 25 micron screen with a paper towel underneath and press gently with a spoon so the towel pulls water through the mesh.
Freeze, then grate
Freeze the damp patty for a few hours, then grate it through a fine rasp grater onto parchment and spread the crumbs thin. Grate it frozen solid, and if it starts to smear, put it back in the freezer for a few minutes. Fine crumbs dry in days. A solid patty can take weeks and may mold in the middle first.
Dry it cold
GNick55 dries in the fridge for 2 to 3 days, then a day or two in a cool room before pressing. A room at about 50 to 60°F and 35 to 50% humidity also works: the cold slows terpene loss, and that humidity pulls water out without drying the hash to dust. Cover it loosely against dust, keep air moving in the room but not across the hash, and break up clumps once or twice a day. Leaving a whole patty out is the risky version, and GNick55 warns that "just leaving out to dry is risky for mold."
Check that it is dry
Dry crumbs stay loose and sandy, don't stick together when you push them with a card, and leave no damp mark on the parchment. If you are not sure, give it another day.
Cardboard or parchment
Members disagree. Some dry on cardboard because it wicks water out fast. Blaze argued the other side: "Never, ever, EVER dry on cardboard or anything else that can absorb the oils and resins from the hash." Parchment or a screen avoids the argument.
Freeze dryers
A freeze dryer finishes in hours and keeps hash light in color, but costs thousands of dollars. Cold air drying works fine for home batches, and GNick55 rates it higher, because a freeze dryer can rupture some heads. See how to freeze dry cannabis flower and hash.
Members compare setups in Need help drying bubble hash, How do you dry bubble hash? and Finishing Bubble Hash.
08 · Guide Pressing and storing bubble hash
Press by hand
Warm a pinch of dry hash in your fingers and work it together, or fold a grade in parchment and roll a bottle of hot water over it. Blaze pressed by hand only, because heavy pressure ruptures the heads. Kneading it into a ball gives the classic temple ball, shown in Homemade Nepalese Temple Ball Hash. For small presses, see My DIY hash press and how to press a small amount of hash.
Hash rosin
Pressing good grades of dried bubble hash between heated plates turns them into hash rosin. See the cannabis rosin guide.
Storage
Wrap pressed hash in parchment and keep it in a glass jar somewhere cool and dark. The outside darkens into a crust as it oxidizes, which is normal and protects the inside. For anything you won't smoke within a few weeks, use the freezer: Blaze recommended it to beginners because frozen hash cannot mold or over-dry. Hash that turns hard and crumbly is usually too dry or carries plant matter. Warm it in your hand and press, and clean hash turns soft again.
09 · Guide How to use bubble hash
In a bowl or joint
Crumble or pinch it on top of flower in a bowl, or roll a thin snake of it into a joint. This is how most members smoke it.
Dabbing
Only the cleanest full melt dabs well. Lower grades leave burnt plant matter behind. Members discuss this in Dabbable bubble hash and What the best way to smoke bubble hash?.
Cooking
The 120 and 25 grades are made for edibles. Decarboxylate first, as in the decarboxylation guide, then see cannabis recipes and edibles.
Hash is much stronger than the flower it came from, so start with a smaller piece than you would of bud.
10 · Pitfalls Common bubble hash mistakes
Over-mixing
Green hash means plant matter, usually from mixing past 15 minutes, a drill on high speed, or material dried to a crumble. Cut the mix to 5 to 10 minutes and make sure the material is frozen solid.
Letting the water warm up
Once the ice is gone, resin softens and stays on the leaf. Keep ice floating through the whole mix and top it up between washes.
Overloading the bags
Too much hash on one screen blocks drainage and strains the seams. Blaze cut batches to 1 to 1.5 pounds in a 20-gallon set and found several small runs quicker than one big one.
Hash that won't bubble
Usually plant matter, leftover water or a low grade. Test a dry piece from the 73 or 90 before blaming the material, and see bubble hash that won't bubble.
11 · FAQ Bubble hash FAQ
Expect about 10% of the dry weight, roughly 40 to 50 grams from a pound of good trim. Of 17 members who posted a return, 14 got between 5 and 15%. Blaze pulled 40 to 60 grams per pound, about three quarters of it full melt. From Blaze's step-by-step thread.
Yes. Break them small. Buds give more and cleaner hash than trim, but you trade ounces of smoke for grams of hash, so most members wash trim and larf. From Questions on using buds for bubble hash.
Either works. Blaze called the idea that fresh frozen hash is unsafe to smoke a myth. It holds more water, though, so dry it thoroughly: one member in the same thread had thrown away more than 100 grams of moldy hash. From water hash with dry or fresh trim?.
Until a wash gives about a gram or less, or the hash turns greenish. GNick55 runs 6 to 8 washes in a machine with dried buds. Blaze, mixing by hand, did one shorter rewash with fewer bags. From how to Bubble washing and tips.
Yes, at lower purity. Shake frozen trim with ice water in a jar, or blend it on low for 2 to 3 minutes, pour it through one screen of about 150 microns into a bowl, and freeze the bowl for about 45 minutes so the heads sink. Siphon off the water and dry what is left. You get one mixed grade. From Blender Method?.
No. Dry ice hash uses no water: crushed dry ice freezes the material in a mesh bag and shaking knocks the heads through. It is faster and needs no drying, but it carries more plant matter, so it is closer to dry sift. Handle dry ice with gloves in a ventilated space. From Dry Ice Hash Into Dabs?.
12 · Guide Other ways to make hash at home
Dry sifting rubs or tumbles dried material over fine screens and needs no water or drying time. Start with What size screens for dry sift?, DIY Hash Tumbler, the cheap trichome shaker and mesh sizing and kief screening. Kief from a grinder or trim bin can be pressed into hash with gentle heat and pressure.
Made your first batch? Post photos of each grade in Concentrates & Processing with the bags you used, your mix time and the starting weight, and the members who wash every winter will tell you what to change.
Sources: about 7,700 posts in THCFarmer hash threads from 2008 on, including Blaze's step-by-step bubble hash thread (2010) and GNick55's bubble washing thread (2024 on), with brand accounts excluded; THCFarmer's earlier guides "How do I make Ice Hash?" and "How can I make ice hash for less than $5 outlay?"; Punja, Sutton and Kim, Journal of Cannabis Research 5:12 (2023); World Health Organization, Mycotoxins fact sheet (2023).
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