Cannabis enthusiast and student of the art of solventless extraction
Bubble hash is one of the cleanest and most versatile of all solventless cannabis concentrates. Made with just cannabis, ice water, and a set of quality wash bags, bubble hash is relatively easy to produce with minimal equipment and processing time. Bubble hash, or ice water hash as it’s also called, can be enjoyed by itself or used as starting material for hash rosin production.
When cannabis material is mixed with ice and water, the resin glands which abound on quality cannabis are broken away from the plant left suspended in the ice water mixture. These resin glands, or trichome heads, are then filtered out of the water using a set of filter screens known as wash bags. Varying pore sizes in the filter screens allow for the collection of different grades of hash. The best hash is collected from filters that have pore sizes most closely resembling mature, full trichome heads. Often, the hash collected from the 90-micron filter represents the majority of the yield and is some of the highest quality as well.
After the hash has been thoroughly dried it can be weighed for total yield. At that point yield percentages can be calculated, which is one of the most popular ways to report yield in bubble hash. Yield percentages are calculated by dividing the weight of the final yield by the weight of the starting material.
Although the process of creating bubble hash is relatively standardized, there are definitely nuances that give extractors a flexibility in their approach. These variables in process account for differences in bubble hash yield from one run to the next.
Bubble hash yield depends on many factors including the cannabis cultivar, the type of cannabis material being washed (fresh frozen or air cured), the number of times the material is washed, length of each wash, the method used to mix the cannabis material and ice water (machine washed vs hand stirred), and the amount of force used in mixing.
All that said, it's difficult to precisely calculate the yield of such an imprecise extraction process as washing bubble hash.
Variables That Impact Bubble Hash Yield
Strains that are perfect for bubble hash production are often referred to as “dumpers”, meaning they readily dump large amounts of mature trichomes when mixed with ice water. Cannabis that’s visibly coated with a thick layer of resin may make for a good hash cultivar, but it’s not a guarantee. Some cultivars, or strains, appear to be good candidates for hash but don’t readily release their trichomes in ice water.
It’s important to determine whether or not your material will produce a worthwhile yield by doing a small test wash. You can learn more about this process in our article on How To Test Wash Cannabis for Hash Production. The specific cannabis strain you’re washing can often be the biggest determining factor in how much yield you can pull.
Type of Cannabis Starting Material
The two types of cannabis material that can be used to wash hash are fresh frozen and air cured. Fresh frozen material is cannabis that’s been frozen immediately after harvest, and remains frozen until washing begins. The other type is air cured material, which is cannabis that’s been harvested and hung up to dry in the traditional way. Fresh frozen material contains much higher moisture content than air cured material, which will account for differences in overall yield percentages. You can read more about the differences between these two in our article about Fresh Frozen vs Dry Flowers for Bubble Hash.
The rule of thumb for calculating wet (fresh frozen) weight to dry (air cured) weight is 5:1. So if you get 4% wet, that’s equivalent to 20% dry.
Number of Times Material Is Washed
Another major factor in bubble hash yield is how many times the same material is washed. One round of mixing and filtering is not enough; the same batch of starting material should be washed several times to thoroughly extract all the resin. The greater number of times the material is washed, the more trichomes it releases. As a rule of thumb, as long as material is releasing trichomes, then keep washing!
However, washing the same material too many times can also lead to additional contamination making its way into the hash. So consider that an excess number of washes can open the door to excess contamination. Find out more about determining the right number of washes in our article about How Many Times To Wash Material for Bubble Hash.
Length of Each Wash
Like the number of washes completed for the same material, the length of time that the material is actively mixed together with the ice water is also a factor in overall yield. A longer length of mixing time can help the material release more trichomes, but overdoing it will also break down the plant matter and cause it to end up in the hash.
So the length of washing time should be kept to the minimum needed to release a good amount of resin with each round. This is often in the 5-15 minute range. Less time washing and a greater number of separate washes can be helpful for the quality without having to sacrifice too much yield.
Machine Mixing vs Hand Stirring
Cannabis material and ice water can be mixed together in a washing machine or by hand with a spoon or paddle. Machine washing can improve yield but if you don’t use a very light “wash” cycle in the machine, then you will likely end up with a lot of contaminants. Hand stirring gives better control and can also deliver exceptional yields if done correctly. Learn more about Hand Washing vs Machine Washing.
Amount of Force Used in Mixing
Similar to the point above, more force used to mix the ice water and material can increase yields. But, this will come at the expense of quality if too much force is used. Excessive force/agitation pulverizes the plant matter and leads to more contaminants in the hash.
So, How About the Average Yields?
All that said, here are the average yields for both types of material used for washing bubble hash:
Dried, Air-Cured Cannabis - 15-20%
Fresh Frozen Cannabis - 3-8%
Also note that the majority of a yield is often found on the 90 micron filter, which is a high-quality hash. So the bulk of the weight also represents a high grade of quality, which is definitely a good thing!
It can be hard to predict yields if you don’t have a consistent washing process in place and you aren’t familiar with the cultivar you’re washing. Getting experience with the ice water extraction method and the cultivar you’re using is key. If you’re not able to hit the expected yield averages, try to improve your process. If that’s not working, you may need a new cultivar.
Keep experimenting and keep learning. Happy washing!
FREQUENTLY ASKED QUESTIONS
How long should you wash the cannabis material?
There’s no exact set time you should wash material, but 5-10 minutes is a good target. In the first couple washes just do a few mins (closer to 5) then in subsequent washes do it longer, closer to 10 mins or beyond. The risk with washing too long is getting excess contaminants.
What if my bubble hash yields aren’t very good?
If your yields are subpar, try to improve your washing process. Experiment with more rounds of washing the same material, and possibly wash for longer with each round. If that’s still not working, it is probably the cultivar you’re washing, which isn’t well-suited for hash production.
Does fresh frozen produce more bubble hash than air-cured buds?
Not necessarily, although some extractors claim that this is the case. Others claim to get better yields from air-cured buds. It really depends on your process and your cultivar.
What is the most important thing that impacts hash washing yields?
Overall, the cannabis genetics (cultivar) you’re washing has the greatest impact on yield. Some strains dump, and some don’t. You can’t get exceptional yields from a plant that isn’t suited for hash production, by virtue of the quality of its resin glands.
How can I improve hash washing yields?
The best way to improve yields is to work with a cannabis strain that’s known for exceptional hash production. Another way is to improve your washing process. Also try to increase the number of washes of the same material. Keep washing until you notice the trichomes are no longer falling off of the plant material.