How To Wash Bubble Hash


Todde Philips 

🇺🇸 Retired veteran, father, rock-climbing expert & rosin connoisseur.

✅ Updated 2/15/21

Properly made full melt bubble hash is the most sought-after starting material that rosin extractors can hope to find. Bubble hash itself is a solventless (chemical-free) extract, composed of isolated trichome heads for a pure and highly concentrated form of cannabis.  

Remember the golden rule: the quality of your rosin depends primarily on the quality of your starting material. To make the best of the best, you need to start with material that’s above the rest. If you’re able to create 5-6 Star bubble hash then it’s good enough to be dabbed by itself, but you can definitely press it as well. 3-4 Star hash makes great source material for rosin and can bring out the very best in that particular cultivar. 

On the flip side, subpar hash will yield subpar rosin. Therefore, knowing how to wash bubble hash the right way is an invaluable skill to have, and will always be in demand.  The following broad strokes overview lists the tools you need and the steps to take in pursuit of the holy grail of rosin source material, ice water extraction bubble hash. 



Before we get started there are a few things to keep in mind. You’ll want to prepare a clean and well-lit workspace where you can easily move around. The space should be as cold as possible, since heat degrades the precious compounds we’re working to preserve within the trichomes. Whenever possible, keep your tools, your space, everything cold.


Water is another critical component that you’ll want to source deliberately. Make sure your water is cold, pure, and preferably reverse osmosis (RO). 

Here’s a list of supplies you’ll need: 

  • Starting material - flowers and/or sugar trim leaves. Want to test a cultivar to find out if it's a good candidate for bubble hash production? Learn how here.
  • 3 buckets or small round garbage cans
  • Set of hash washing bags. The Press Club has you covered. 
  • Plastic or metal mixing spoon (avoid wooden spoons as they are more likely harbor contaminants and are more conducive to mold and mildew growth)
  • 10-15 pounds of ice for each pound of flower
  • Filtered or Reverse Osmosis (RO) water
  • Clean, large sheets of cardboard
  • Parchment paper 
  • Sieve or Microplane
  • 1 or 3 gallon sprayer


Now let’s get to it! 

We can think about ice water extraction in four main parts: chilling and mixing, filtering, microplaning/sieving, and drying.



Chilling and Mixing 

The first step is to wash and inspect all your equipment to make sure everything is nice and clean with no rips in your bags and stitching. It's a good idea to pre wash your bags to flush out any loose fibers. Fill your sprayer and one wash can with a mixture of clean ice and RO water. How much material you have will determine how much water you need. The goal is to keep the cannabis material and ice in a state of suspension for 30 minutes to ensure everything is as cold as possible.

Place your microplane in the freezer and prepare a shelf in the freezer for your hash, a towel, and your 25 micron screen for wicking (which should come with your set of hash filter bags). Next place the 220 micron bag inside of your wash bucket, inside of which you’ll wash the starting material.  Put a layer of ice on the bottom of the bag, then a layer of cannabis, then another layer of ice on the top to create a cap. Pour a mixture of cold ice water from your other bucket slowly over the ice cap, filling the can so that the mixture is in suspension. 

Let this soak for 30 to 40 minutes. This prepares the trichome heads to be cleanly separated from the stalks with minimal breaking away of additional plant material.  After you’ve let it soak, stir with a metal or plastic mixing spoon for 10 minutes. If you want to enjoy the bubble hash by itself, as opposed to using it for rosin production, limit stirring for 5 minutes. After stirring, let it sit for 1 to 2 minutes to allow the trichomes to settle to the bottom of the wash can. 



Pull out the 220 micron bag, making sure to squeeze all the water from the bag. Layer your wash bags into the other wash bucket, starting with the smallest micron first and ending with the largest micron on top. Now, dump all the water through your filter bags.



Instead of stacking each filter bag directly on top of the next, you can use a bucket stacking system to keep the filters from sagging into each other. Check out our article about How To Build a Bucket Stacking System for Washing Hash. 

Before you pull your bags, spray them to make sure the sides to make sure all the trichomes have fallen down onto the screen. Pull each bag slowly and shake the water. Spraying water over the bag beneath it allows the trichomes that might be trapped to fall into the bag below. 

Stretch the bags so you can carefully spray the hash to filter any particulates that are trapped. If air drying it's very beneficial to patiently wait for all water to drain, then scoop onto the 25u screen and press all the water out. Put the micron screen and hash into the freezer to thoroughly freeze for 24 hours. 

Microplaning/Sieving and Drying 

After it’s frozen, remove the hash and take either sieve or microplane and break apart the hash over parchment paper inside of a clean pizza box as thin as possible. The idea is to create a very thin layer of hash that can dry evenly. Avoid clumps and try to break it apart with the microplane as thoroughly as possible.  Place in a cold room around 40 to 50 degrees Fahrenheit for about a week or so, until completely dry. 


Here’s a simplified step-by-step outline of the process:

1. Put the 220 work bag into the wash can - this is the bag that holds the material during the wash. 

2. Inside of the wash bag, create an ice and material layer cake. First put ice on the bottom of the bag then material, then more ice. No need for a thick layer, use just enough to cover the material. Then put a nice layer on the top to create an ice cap. You can also wash the hash without the work bag, directly inside the bucket. Then pour the mixture through the work bag to filter out the material before continuing to pour through the smaller micron filters. 

3. Pour the cold ice water from you other bucket slowly over the ice cap allowing the can to fill

4. Let soak for 30 to 40 minutes. This time allows your material to thaw or rehydrate, depending on whether you’re using fresh frozen or dried/cured. This soak helps minimize the amount of plant material that will break away with the trichome heads. You want as little plant material breaking away as possible. 



5. Using a large metal or plastic mixing spoon or paddle, stir consistently for 5 mins if your end goal is just the hash. If you’ll use the hash to press rosin, stir for 10 mins. Keep a constant current going within the ice water slurry, as the current within the water will allow the trichome heads to separate.

6. Let the material sit for 1 to 2 minutes to allow the trichomes to settle to the bottom of the wash can. 

7. Pull your 220 bag and drain all the water out of the wash bag and place it in the bag in a remaining can. 


8. Stack your filter bags in your 2nd can, starting with the smallest micron size and working up, so that the largest micron is the bag at the very top. This will be the first bag you pour through.     

9. Dump the water through your filter bags 

10. Spray the bags using purified or RO water and a sprayer just to make sure the side of the bags are clean.   

11. Pull each bag slowly and shake the water. Spray each wet hash patty over the other bag, allowing the trichomes that might be trapped to fall into the bag below. 

12. With each bag you pull, repeat this process then stretch the screen across a frisbee or the top of a small bucket to spray and filter any particulates that are trapped 

13. Take cleaned hash and scoop onto freeze dryer tray if you have access to a freeze dryer 

14. If air drying, you want to allow all water to drain and scoop onto the 25 micron screen, then press all the water out. Remove the patty and put into the freezer to freeze. 

15. If air drying take the frozen patty out and take either sieve or micro plane and break apart the hash patty over a sheet of parchment paper inside a clean pizza box. Aim to created a layer of hash that's as thin as possible, as this will allow for the most efficient drying. 

16. Place in a cold room around 40 to 50 degrees Fahrenheit for about a week or so. A wine cooler can provide a nice environment for drying. 

17. If you’re using a freeze dryer, scoop onto trays and tap to thin, freeze for 4 to 6 hours depending on thickness then dry for 16 to 20 hours. 

18. Once the hash is done drying, collect and scoop into a rosin bag for pressing, such as this 37 micron from The Press Club), or keep as hash to enjoy on its own.




Making bubble hash is an art. Producing true 6 star hash takes years of practice, so don’t be frustrated if your first couple runs are less than stellar. Check out this article to find out how to rate your hash.  You won’t become the next Frenchy overnight. Just get started and don’t be afraid to make mistakes. Focus on consistent improvement over time and your skills will be the envy of all your friends. Full melt hash is always in demand and presents connoisseurs with a great way to enjoy premium cannabis.  



What is the hardest part about washing hash?
Possibly the hardest part about washing hash is keeping everything very cold! From the water to the tools to the ambient air in the room, everything should be kept as cold as possible. This can be challenging depending on the temperatures in your area. 

What is full melt bubble hash?
The highest grade of hash conceivable, Full Melt Hash evaporates fully when heated and leaves no residue behind. Find out how hash is rated in our article about How Bubble Hash Is Rated.

What is the best size micron filter bag for collecting hash?
The best hash will be collected from filters in the 45-125 micron range. The 75-micron bag will often yield the very best hash. 

Is is better to sieve or microplane fresh hash for drying?
Sieving is less abrasive on the trichome heads than microplaning, so sieving is the recommended approach to prepare hash for air drying. 

How much ice do you need to wash hash?
The amount of ice needed depends on the amount of water you're using to wash hash. Enough ice should be added to keep the water at near-freezing temperature levels, but not so much ice that it crowds-out the cannabis material. Ice is needed to chill the water and keep it cold, however it's not otherwise beneficial to the process of separating the resin from the plant material (vortex of the water performs the mechanical separation). 


1 comment

John Harris

Great info just what I was looking for. Thanks

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