How Many Times Can I Wash Cannabis for Bubble Hash?

Todde Philips   

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


Cannabis material requires multiple rounds of washing and filtering to fully realize its potential during the ice water extraction process. Rarely will cannabis dump all it’s resin glands in just the first wash. 5-10 rounds of washing is not uncommon to fully process a single batch of material, and even then it’s possible that some medicine is left behind. 

So how many times can you really wash a single batch of material for bubble hash? And what are the factors to consider when deciding how many rounds to wash the same material?

In short, there’s not a specific formula to give you the exact right number of times you should wash your material. There are signals to help guide you, but remember that extraction is an art as much as it is a science. Getting clear on your objectives before starting your wash will help you make the right call as to when it’s time to retire your material and begin another batch. 

So you might ask “why not wash the material just once for an extended period of time, rather than repeating several separate washes?". You could wash only one time, but you risk over-doing the agitation and beating the material to a pulp, which leads to contamination in your hash. Either that, or you’ll leave a significant amount of good resin behind. 

Let’s look at some things to consider when determining how many times to wash your cannabis for ice water hash



Multiple washes only make sense when material is dumping resin. Much of the quality of the starting material depends on the specific cultivar, and some cultivars are better for washing hash than others. Cannabis strains that produce copious amounts of capitate stalked trichomes with skinny “necks” are generally best. 



The neck refers to the minuscule segment of the trichome that connects the head to the stalk, and cultivars that can easily release the head from the stalk are ideal. 

Material that’s been carefully grown and properly harvested for optimum ripeness won’t wash very well if it’s not in the genetics. Even while the entire cultivation process may be fully dialed in, the specific cultivar you choose for washing hash is still the dominant factor. For a review of some of the superstar cultivars, check out our article on The Best Strains for Washing Hash

If you’re not sure how the strain will perform, you can do a test wash of the material. We put together a guide to help you with a small test wash, which is basically a mason jar and some ice water. No need to risk an entire run just to see how the material will respond to ice water extraction. 

Air-Cured or Fresh Frozen?

Fresh frozen can give you better quality of hash, largely in terms of terpene content. However the quality tends to noticeably diminish after the first couple of washes. Fresh frozen has a tendency to release more chlorophyll than air cured material, especially as the number of washes increases. 

Air cured material delivers more consistent results throughout multiple series of washes. Therefore, you can extend the number of washes with air dried without risking a significant decrease in quality from the first wash to the last. 

That said, it’s recommended to be more conservative with the number of washes when you’re using fresh frozen material vs air cured material

Your Hash Production Objectives

Another factor to consider in the number of washes is your ultimate goal for hash production. Are you looking to maximize quality or maximize yield? Pushing the limits of the number of washes that your material will accommodate can lead to greater yields, but it can come at the expense of overall quality. This is especially true with fresh frozen cannabis. 

If premium quality is your focus, there’s no need to continue running material until absolutely all of the resin hash been released. It’s okay to leave some trichomes behind, as they can be extracted in other ways (infusions, edibles, MCT oil capsules, etc.).

To optimize for quality, several shorter washes are better than a couple longer washes. To optimize for production efficiency, a limited series of longer washes will reduce costs and labor. The key is finding the ideal balance between the two. 

Hand Washing Versus Machine Washing

Whether you’re hand washing or machine washing your material can impact the number of washes you’ll complete. While hand washing hash is obviously more labor-intensive than washing with a machine, it gives you greater control over how you handle the material and makes it less likely to pulverize the material and contaminate the hash. With a more gentle and less aggressive hand washing technique it’s possible to have more washes with higher quality outcome, as opposed to a machine that can overdo the agitation and contaminate the hash. With a machine, you may not be able to do as many washes without compromising quality.  



Sense and Respond to the Definitive Signals

All things considered, if the material is still dumping resin and you’re collecting the uncontaminated heads from your wash bags, then keep washing! What you want to see is strong yields with every round of washing and filtration. 


What you don’t want to see is excessive contamination, apparent when the resin takes on a green hue as it pools together on top of the mesh filters of your “keeper” bags (namely the 75 micron). This excessive contamination means it’s time to stop washing, or that the material is being overworked with a super aggressive mixing. It can also be a combination of both!

So run your material until yield tapers off and the quality is diminishing, not some arbitrary number of times. Remember to toss the first batch of water and always add more ice as needed to keep everything very cold. Always reverse your wash bags and rinse them well between runs. 

A common scenario is 5 sets of 5-10 minute washes. The first few runs are best with shorter times, maybe 3-5 minutes. Subsequent washes extended to around 10 minutes or more. Don’t rely strictly on these parameters, but rely on your own sense of judgement and the objectives you have for production. 

Reusing Cannabis Material After Washing for Bubble Hash

After the material has given its best for ice water hash production, it still may contain some medicine that’s worth extracting. Using the material for infusions and edibles is a great way to get every last bit. 

After the ice water extraction has been complete, lightly squeeze out excess water and spread it out thinly over a clean surface to dry. Ideally it should be in a room with minimal light (reduces cannabinoid degradation) and plenty of airflow. Mold is a big risk with wet cannabis, and this should be the primary concern. Any mold growth will ruin the material. 

Once the cannabis is dry, you can decarboxylate it and then infuse into butter or oil to be used in all kinds of recipes. You can also use the decarbed material to make MCT oil capsules, which are one of our favorite ways to reuse washed material. 


Cannabis material will tell you how many times it should be washed, if you only know how to listen. Pay attention to the quality and amount of resin that you’re collecting after each round of washing. If the material is still releasing quality hash, then keep washing. 

Solventless extraction is an art, so be sure to enjoy it! 





What kind of contaminants can get into bubble hash?
Tiny pieces of cannabis plant material are the most frequent types of contaminants, and this creates a greenish hue for the hash. Other contaminants can include dust, dirt, and microscopic pieces of pests which can be more common in cannabis grown outdoors. Mixing the cannabis and ice water the right number of times and with the right amount of agitation helps keep contaminants out of the final product.

What if I wash cannabis too many times?
Washing cannabis material too many times can lead to excessive plant material getting into the hash (by pulverizing the material) and a greatly reduced yield during the final washes. Continuing to wash material after it's already dumped the majority of its resin is often not worth the time.

Should I throw away cannabis that's been washed for bubble hash?
The cannabis material you've washed multiple times for bubble hash production still contains medicine. You can dry the material, decarb it, then use it for edibles and MCT oil capsules. However, it's not an egregious mistake to throw the material away after washing, as it's already given up the best it has to offer. 

Is it better to hand wash or machine wash cannabis for bubble hash?
Both methods can deliver great results, however we recommend hand washing for the level of control it gives the extractor. Hand washing lets us mix the material with just the right amount of agitation and lessens the chances that the material is overly-worked and pulverized.

Do I have to test my material before washing it for bubble hash?
It's not necessary to test your material, but if you don't know how it will perform in the wash, it's recommended to do a mason jar test to see how well the material will release its resin. Better to test the material first than potentially waste an entire run of material that doesn't produce well for bubble hash.



1 comment

James Gillette

Why did you specifically mention about changing the water the first run? Does that mean its ok to reuse some of the water? Especially since it will already be super cold, it would be less ice you would need to add.

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