Do I Need To Freeze Fresh or Cured Material Before Washing?

Viviane Schute        

Cannabis enthusiast and student of the art of solventless extraction


We know that cold temperatures are a necessity for producing high quality bubble hash with the ice water extraction method. Cold temperatures make trichomes on the cannabis material brittle enough to fall away from their stalks, while also minimizing terpene loss and helping to keep resin contained within the trichomes. But do we have to actually freeze cannabis material before beginning the process of washing hash?

First, let’s look at the different preparations possible for cannabis material used for washing bubble hash. 

There are three different states in which you can use cannabis material for washing for bubble hash. The first is fresh frozen cannabis, where the plant is frozen to subzero temperatures immediately after harvest. So by definition, we absolutely must freeze the fresh frozen material immediately after harvest. The goal is to preserve the live qualities of the flowers and keep it frozen until it goes into the mix for extraction. 

The second possible state is dried and cured cannabis, where the flowers are hung to dry and then lightly cured in the traditional method prior to ice water extraction. This is the original type of starting material for ice water extraction, and how the process first came to light. Dried and cured is the best type of cannabis material to wash if you’re just getting started with washing bubble hash.

The third possible state is live cannabis, where the plants are harvested from the garden and immediately put into bubble hash production. In this way, plants go from the garden and directly into the washing machine for extraction. This is only feasible in areas where you can work in a cold environment with a lower humidity. Warm temperatures and high humidity can render the fresh and live resin untenable to work with. During harvest season in the mountains of California it’s possible to wash hash outside with live cannabis material pulled straight from the plant, trimmed of fan leaves, and placed into the machine for mixing. 




Since we know that fresh frozen cannabis material is always frozen prior to washing for hash, let’s look at the other two types of material: dried and cured, and live. When we’re working with dried and cured and live cannabis, is it really necessary to freeze the material before washing for bubble hash?

Should I Always Freeze My Cannabis before Washing Hash?

The answer is no, you do not need to freeze dried and cured material, or live material, before washing hash with ice water extraction. 

While frigid temperatures are of utmost importance for ice water extraction, actually freezing material before washing hash isn’t any more beneficial than simply letting the material become ice cold while it’s pre soaking. 

Frozen or not, pre soaking is required regardless of the type of cannabis material used. Before ice water extraction begins, it’s essential to ensure the material is completely saturated with water in order to keep the cannabis soft and supple. By doing so, the material remains spongy and springy while it mixes in the vortex with ice water, making it much less likely to break apart into tiny pieces of contamination which will end up in your hash. 

Read up on the right way to pre soak cannabis in our article How To Pre Soak Fresh or Cured Material before Washing for Ice Water Extraction.

The benefit to freezing cannabis is preservation of the qualities of the live plant, specifically terpene content. This is the beauty of fresh frozen cannabis. If extractors are unable to move the plants from the garden immediately after harvest into the washing machine for extraction, then flash freezing the material is a great way to maintain the live essence of the plant. 



Freezing live cannabis could actually prove to be detrimental to the process, if that material could otherwise go right into the washing machine for hash extraction. This stems from the condition known as ice nucleation, in which freezing temperatures cause chlorophyll to explode out of plant tissues which circulated it while living. This free-floating chlorophyll can very easily bleed out into the water as the material thaws during extraction. And this form of chlorophyll, as a result of ice nucleation, is some of the hardest to rinse out of your hash, leaving you with higher levels of contamination in the final product.  

Learn more about ice nucleation in What Is Ice Nucleation in Fresh Frozen Cannabis?


Unless your aim is fresh frozen cannabis, you can skip the step of freezing your material just prior to washing for hash. Pre soaking cannabis in ice cold water makes trichomes brittle and readily able to break away from their stalks. This is the extent of the “freezing” needed for both dried and cured, and live, cannabis material. 

This is good news, as it saves both time and resources in the ice water extraction process. If you’re new to washing hash, the best approach is to dry and cure your material, pre soak, and then begin the wash. Want a review of the entire process? Check out our guide on How To Wash Bubble Hash.  

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What is live cannabis material?
This refers to material that has just been harvested. It’s possible to wash live material for bubble hash, by taking cannabis right from the garden and putting it directly into the washing machine for ice water extraction.

Do I always have to freeze cannabis before washing bubble hash?
No, you don’t have to freeze cannabis before washing bubble hash. You can take dried and cured or live cannabis just as it is and begin ice water extraction. 

Can you put cannabis from the garden directly into the washing machine for ice water extraction?
Yes, it’s possible to harvest cannabis and begin washing it immediately for bubble hash. Be sure you’re working in cool temperatures with a lower humidity. 

What is the benefit of freezing cannabis?
The benefit of freezing cannabis is to preserve the qualities of the live plant, specifically high terpene content, when there’s a lapse in time between harvest and extraction. Fresh frozen cannabis refers to this type of material preparation, and it’s useful when harvesting and then immediately washing cannabis for bubble hash isn’t feasible. 

How can I make sure my cannabis material is cold enough before washing bubble hash? The best way to prepare cannabis for ice water extraction is to pre soak the material in ice water inside your mixing bucket or washing machine. Learn more about pre soaking in How To Pre Soak Cannabis for Ice Water Extraction.


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