What Causes Green Bubble Hash?

Viviane Schute        

Cannabis enthusiast and student of the art of solventless extraction


Although vibrant hues of green are often associated with high quality cannabis, it’s actually not a good look for bubble hash. Bubble hash is composed of cannabis trichome heads, the bulbous resin glands that give cannabis flowers that crystalline, sugary look. These heads range in color from clear to amber, but never green. 

Trichome heads appear clear in their early weeks of development, turn milky as they approach ripeness, then finally become amber as the resin inside reaches full maturity. These delicate amber and honey-golden hues are seen in high quality grades of bubble hash and rosin. 

The quality of bubble hash is based largely on the percentage of full, mature trichome heads to any other bits of plant material, including trichome stalks, plant particulates, etc. The best hash is all trichome heads without any plant contamination. 

We can attribute the green appearance in some batches of bubble hash to excess plant matter contamination. Green is a signal of contaminated hash. 

This green color comes specifically from plant chlorophyll.

What Is Chlorophyll?

Chlorophyll is the green pigmentation that’s found in plants. Chlorophyll molecules are vital for plant photosynthesis, the process that allows plants to absorb energy from sunlight. There are multiple types of chlorophyll, all of which are considered undesirable in cannabis concentrates. 


Although there’s nothing wrong with ingesting chlorophyll (we eat it every time we eat plants, and inhale it every time we smoke flowers), it doesn’t enhance flavor or effect. In fact, chlorophyll negatively impacts the taste of solventless extracts. 

Chlorophyll is not present in trichome heads, the objects of pursuit in hash making. When done correctly, ice water extraction produces hash that’s almost entirely trichome heads. 

So why does some hash contain enough chlorophyll to take on a green appearance?

Factors That Contribute To Chlorophyll Contamination

Incorrect Agitation
Ice water extraction, the process used to collect loose resin, or bubble hash, involves mixing resin-rich cannabis and ice water together. This swirling and mixing motion is called agitation, and it allows trichome heads to break cleanly away from their stalks, just as a ripe apple falls from the tree. Agitating ice water and cannabis is actually a somewhat delicate task. Brute force is a great way to create excess plant contamination, and green hash. 

Using a hand drill with a paint mixer is an example of aggressive agitation that can easily turn your hash green. Mixing in a washing machine with a heavy duty setting is another way. In both of these examples, the force of these machines can actually shear the cannabis material, releasing chlorophyll inside. The material should be mixed together with the water to allow trichomes to release, the trichomes don’t need to be beaten off of the plant.

If you want to use washing machines to wash hash, make sure they have a low or delicate setting. The goal is to create a vortex within the water, and this current will be all the force needed to separate the heads from the material.  

Learn more about the different ways to wash hash in Hand Washing vs Machine Washing Bubble Hash.

You can also get green hash by mixing/agitating the cannabis too long, or using the same material for too many runs. Read more in How Many Times Can I Wash Cannabis for Bubble Hash?

Too much ice can also crush the cannabis material, and grind it to a pulp. Only use the minimum amount of ice needed to keep everything nice and cold. 




Mishandling Starting Material
Fresh frozen cannabis is arguably the premium starting material for washing hash. Freezing cannabis preserves its terpene content and slows degradation of the plant’s most valuable compounds. However, it also makes the material more vulnerable to imparting massive levels of chlorophyll contamination if it’s not handled correctly. 

Fresh frozen cannabis easily shatters when handled. Once the material is vacuum sealed and stored in the freezer, don’t take any bags out until you’re ready to wash. Moving the bags around will cause tiny pieces of plant material to splinter off inside the bags. Much of these plant contaminants will end up being the size of trichome heads, and therefore end up mixed in with your hash. 

When you seal the material in the bags right after harvest, leave enough air inside to act as a cushion, similar to a bag of chips at the store. This protects the buds from squishing into each other with a lot of force, which would bruise and damage trichomes. 

Always be gentle when handling cannabis, especially when it’s frozen. 

A note on harvesting cannabis for washing hash: don’t cut leaves across their veins, or leave large chunks of stems attached to the flowers. Cut leaves off at their base, and don’t leave stems. If you can’t cut a leaf away at the base, then leave it. Cutting a leaf will expose the veins and leak chlorophyll while washing. 

Using scissors, work your way up the base of a large flower, removing quarter-sized chunks of flower at the base of each of the smaller stems. Every large bud is composed of smaller buds packed together, and it’s these smaller segments that you want to be working with.  

Also, stems will leak chlorophyll, so don’t include the big stems with your material to wash. 

Keeping water ice cold while washing hash is an important factor to always consider. The cold temperature makes it easier for the heads to separate from their stalks, and for the resin to stay safely protected inside the trichome membrane. But there’s another reason that ice cold water is so important, especially when working with fresh frozen material. 



When cannabis is frozen immediately after harvest, the water inside the plant freezes, creating tiny ice crystals throughout. These ice crystals actually rupture the insides of the plant, destroying barriers that keep chlorophyll contained. 

Warmer water allows fresh frozen material to thaw, which releases the chlorophyll that was previously frozen. To prevent this, it’s critical to prevent the material from thawing out. Water should hover just around freezing levels. 

Read more about this in What Is Ice Nucleation in Fresh Frozen Cannabis?

Can You Remove Chlorophyll Contamination?

You can reduce the amount of contamination, yes, but it’s hard. And often, you won’t be able to completely reverse the contamination. Damage control is not a great option, prevention is much better. 

Rinsing loose resin in the bubble bag with a high pressure stream of water prior to collection helps wash chlorophyll-rich material material through the mesh. Rinse the hash for several minutes with a jet stream of ice cold, clean water, and this will force contaminants through the sieve. But if there’s a lot of chlorophyll in the hash, this won’t remove 100% of contamination.

Hash makers are constantly innovating. For example, Brett Byrd of Byrd Extracts in Mendocino County, CA developed a vacuum system that allows you to pull out green contamination from hash with impressive accuracy. 


Naturally-occurring chlorophyll in the cannabis plant is the cause of green bubble hash, but fortunately there are ways to minimize your chances of ending up with an emerald extract. Be delicate and deliberate when washing hash, handle fresh frozen material with special care, and keep water temperatures near freezing during agitation and you will decrease the likelihood of ending up with green hash. 

Rinsing the heads for a couple minutes in a jet stream of ice cold water prior to collection is another best practice for keeping plant contamination to a minimum. 

Also check out our article Why Does Bubble Hash Have Different Colors?

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Why does hash turn green?
Hash turns green due to excess chlorophyll present in the hash.

What is chlorophyll?
Chlorophyll is the green pigmentation that’s found in plants. Chlorophyll molecules are vital for plant photosynthesis, the process that allows plants to absorb energy from sunlight. Although it's safe, chlorophyll is considered a contaminant in hash. 

Can you clean up green hash?
Rinsing the hash with a jet stream of water while it's still in the bubble wash bags is a good way to clean hash, but it may not completely remove the chlorophyll. Prevention is the best approach. 

Can you smoke green hash?
Yes, it's okay to smoke green hash, but it will not the highest quality. 

What is the best color for bubble hash?
Good hash runs the spectrum from light gold to dark brown. 


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