Dry Sift 

Another concentrate with a long, storied history, dry sift is made by rubbing cannabis over a screen with extremely fine mesh to separate the resinous trichomes from the surrounding plant material. The tradition dates back more than a thousand years in Morocco, which remains the world’s largest exporter of cannabis resin, according to the United Nations Office on Drugs and Crime.

Dry sift works because cannabis resin—prized for its psychoactive potency and therapeutic properties—is found primarily inside trichomes, the globulous balls that give high-quality cannabis the appearance of being covered in crystals. By agitating buds over a fine mesh screen, a dry sift hashmaker artfully knocks these trichomes loose, so they fall through the screen.


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The most skilled dry sifters collect and press these trichomes intact, with as little plant material as possible slipping through the screen. Though far from the highest potency concentrates, dry sift hashish does enjoy a reputation for retaining the terpenes and terroir of its source material. Moroccan dry sift in particular is believed to offer a high-CBD profile compared to most commercially available cannabis.

Bubble Hash

Mila Jansen was born in Liverpool in 1944, but grew up largely in Holland. She smoked her first joint in 1964, the same year her fellow Liverpoolians the Beatles tried cannabis for the first time. A year later, she opened a boutique called Kink 22 that quickly transformed into one of Amsterdam’s earliest “tea houses”—a forerunner of the modern cannabis coffeeshop where on-site consumption was common, but no sales took place.

The Ice-O-Lator took things a huge step forward based on a simple insight: cannabis resin is an oil and not water-soluble.

When the authorities closed in on Kink 22, Jansen moved her family out of the country, traveling widely for the next twenty years, before returning to Holland and finding work in the flourishing “homegrown” cannabis cultivation scene.

While the coffeeshops, once underground themselves, had become officially tolerated by Dutch authorities in the mid 1990s, all cannabis growing and importation remained in the shadows. Seizing an opportunity, Jansen designed two machines that transformed the countless pounds of “trim” (otherwise discarded leaves trimmed off cannabis buds) produced by her fellow growers into highly prized concentrates.

“Trash to stash,” as the now old saying goes.


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Her first invention, the Pollinator (circa 1994) basically automated the dry sift process on a small scale. The Ice-O-Lator (circa 1998), meanwhile, took things a huge step forward based on a simple insight: cannabis resin is an oil and not water-soluble. So if cannabis is submerged and then thoroughly agitated, its prized oil can be far more easily separated out.

A series of interlocking bags with mesh screens of various micron sizes in the bottom, the Ice-O-Later system works by using ice water and agitation to freeze trichomes and break them off from the plant. Then the water is poured through the bags, and resin is collected in the screens.

At the finest micron sizes, this produces concentrates so pure they bubble and then largely evaporate when touched with a flame. This led to the short-lived adage among extreme hash snobs that “if it don’t bubble, it ain’t worth the trouble.”



The art and science of optimally concentrating cannabis is, in large part, a process of concentrating cannabinoids—the unique chemical compounds found in the plant. Chief among these cannabinoids, of course, is THC, which is prized for both its therapeutic benefits and psychoactive properties.

But over the last ten years or so, as our understanding of cannabidiol (CBD) has grown, there’s been increasing demand for concentrates rich in the non-intoxicating but powerfully medicinal compound. Most notably, CBD-rich concentrates can provide profound anti-seizure properties to epilepsy patients without the high of THC—a game changer both medicinally and politically; taking euphoria out of the equation removes a major barrier to societal acceptance of pediatric use.


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While researchers and cannabis activists have long understood the benefits of CBD-rich cannabis oil, the game didn’t truly change until CNN Chief Medical Correspondent Dr. Sanjay Gupta’s 2013 special report introduced the world to Charlotte Figi and other children successfully using wholly plant-derived CBD-rich cannabis concentrates to treat otherwise intractable Dravet syndrome and other serious ailments.

CBD can also provide powerful anti-pain, anti-inflammation, and anti-anxiety relief, making CBD-rich concentrates one of the fastest growing segments of the legal cannabis market.