Solventless hash, or hash that is made without the use of harsh chemical solvents, has made a resurgence in the last few years. Perfected in the 1980’s and 1990’s, methods of extracting the THC laden trichomes using only ice, water, screen filters and physical agitation. When legal cannabis markets started to opened up, solventless hash got overshadowed by hydrocarbon extraction. Not long after, a new solventless extraction method was developed using only heat and pressure to create a product called rosin.

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As consumers' preferences have begun to shift, we are seeing demand for solventless extracts increase. Without the use of dangerous equipment and explosive gasses, solventless is preferred due to the chemical free extraction processes for manufacturing.

With this increase in demand, a need for cannabis genetics that are grown and tailored to suit the needs of extractors has arisen. Growing solely for the purpose of solventless extraction is slightly different from cultivating raw flower. When growing for solventless, you are essentially “resin farming” – growing to maximize the amount of extractable trichome heads.

Trichome Traits to Look for When Resin Farming

A trichome is made up of a head and a stalk, much like a tiny mushroom. The head is a bulbous sack where THC and terpenes are formed. The head sits above and is attached to the stalk which is made up of plant waxes that provide the structure of the trichome. In solventless extraction, you are after the trichome heads only. The less plant wax from the stalks, the better the quality the final product will be.

 A macro shot of clear trichome heads on a cannabis plant that appear like tiny mushrooms The most important thing to look for when resin farming is the quality of the trichome head. photo credit
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Some strains produce better results and yields than others when going through the solventless extraction process. This is due to the variance of the amount, size and shape of the trichome heads and how strongly they are attached to the trichome stalk. These traits are all controlled by the plant's genetics, meaning some strains by nature just yield better or create better quality solventless hash than others. This means not all trichomes are the same and we need to be able to judge what qualities make a trichome that will extract well.

A solventless extractor can use a cheap handheld 40x microscope to judge how well a strain is suited for extraction by taking a peak at the microscopic trichome forest. Below are some of the key hash performance metrics to look for.

Hash Performance Metrics
1. The size of the trichome heads- different-sized trichome heads require different-sized screen filters. Larger trichomes also contain more THC and terpenes.
2. The length of the trichome stalk- longer trichome stalks mean the potential for more plant waxes. Also, measuring the stalk length can help the extractor gauge what screen size will be needed to filter them out.
3. How thick the connection to the stalk is- this can help you gauge how well suited the trichome is for extraction. A thicker connection means more agitation will be needed to break off the head from the stalk, and too much agitation can lead to plant matter contaminating the final product. A weak connection is better for extraction.
4. Trichome density- how many stalked trichomes are there? Some strains will pack more trichomes than others into the same area. If we are growing for solventless production, we want an extremely high trichome density to get the highest returns.
5. Also important to know is there are two types of trichomes- Capitate sessile and capitate stalked. Capitate sessile are like tiny microscopic hairs, which are made of plant wax and contain no THC. Capitate stalked are the trichomes with the heads and stalks, the ones we want. Different strains will have different ratios of sessile to stalked, one with a low sessile to stalked count would be better suited for solventless extraction. Sessile trichome size also needs to be considered for screen size and filtering as well.

Strains That are Ideal for Resin Farming

Main old-world hash strains have been bred for generations to have such trichome qualities. Through the process of trial and error coupled with experience and selection, strains like Hash Plant, Hindu Kush, and Afghani were developed over centuries with trichome extraction in mind. These strains can be traced back in the lineage of most of the popular modern-day strains, so finding strains that have good extraction qualities shouldn’t be too hard.

A close-up image of an afghani plant that has a light green color, orange pistils, and clear mushroom-like trichomes Afghani was used for centuries for hash making.
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Strains like Wedding Cake and Strawnana make exceptional solventless extractions, but for different reasons. Wedding Cake has a high return and makes a great, and potent extract. Strawnana doesn’t yield as much, but the flavor is unbelievably delicious. When considering strains for solventless extracts, you need to consider what your goal for the end result is going to be. If you are trying to get the highest returns, you might be resin farming a different way than if you are trying to go for the highest quality.

In Conclusion

Resin farming has been born out of the need for maximum trichome production to fill the demand for that tasty and terpy solventless bubble hash and rosin. As the techniques for resin farming continue to develop, so too will the cannabis genetics used begin to change as we put a new selective pressure on the crop. It will be interesting to see how resin farming and genetic selection for hash production will change the cannabis gene pool in the coming future. Until then, happy resin farming!

Photo Credit: Shutterstock

Frequently Asked Questions

Why Do Some Plants Have Better Trichomes Than Others?

Genetics. The potency and aroma of cannabis is due to the chemistry going on inside the trichome heads, which is all driven by the plant’s genes. Not all trichomes are the same.

What Strains are Better for Making Solventless Hash?

Most of the current “Cake” strains yield pretty decently. Cookies and Cream is another decent yielder. Also, Strawnana makes an incredibly flavorful extract.

What is the Best Quality of Hash?

Ice water extracted hash, that then is pressed in a rosin press.

Is OG Kush Good for Hash?

It makes high-quality hash but doesn’t yield as much as other strains.

Are Sativas or Indicas Typically Better for Solventless Concentrates

Most modern indica strains were bred from old-world indica genetics. These old-world strains were cultivated for millennia specifically for use in hash production. Some sativa hybrids have a trichome structure that makes them perfect for hash production.