What Are Solventless Concentrates?

Solventless concentrates are products that are made by refining cannabis plant material mechanically to isolate the trichome heads that contain the plant’s essential oils, terpenes, and cannabinoids. These concentrates are typically highly potent, with a much higher THC content than flowers; whereas a cured flower typically contains between 15 and 30% THC, concentrates made with the same flower could contain anything between 50 and 90% THC.

With cannabis becoming legal in more and more cities, such as Seattle, Washington, today's cannabis industry is pioneering new and improved products that appeal to a wide range of consumers. According to an article in the Seattle Times, concentrates accounted for 35% of Washington State’s legal cannabis market in February 2023, proving its appeal as an alternative to cannabis flower.

What Are Solventless Concentrates?

Solventless cannabis concentrates are products that are produced by separating the trichomes or resin from the cannabis buds mechanically rather than dissolving the active compounds using chemical solvents such as butane, propane, hexane, CO2, or ethanol. Mechanical methods include manual agitation (charas), sifting (kief, hashish, and dry sift), ice water and agitation (bubble hash), and heat combined with pressure (rosin). 

Because these processes preserve the starting ratio of terpenes, flavonoids, and cannabinoids in the cannabis flower faithfully during the extraction process, solventless concentrates are appealing to cannabis enthusiasts who want to experience the true aromas, flavors, and effects of each strain and without any chemical alterations or hydrocarbon overtones.

How Are Solventless Concentrates Made?

There are several methods that can be used to make concentrates without the use of solvents. These include rubbing, sieving, ice water extraction, and pressing cannabis material between heated plates. No chemical solvents are used in solventless extraction, meaning that the resulting extract doesn’t require purging to remove any residual solvent. Furthermore, bacteria and mold aren’t removed in any of the solventless extraction processes described, so the starting material is typically of a very high quality to ensure an end product that passes lab-testing requirements.

Kief 

Kief is made by sieving dried buds or trim to separate the trichomes from the plant matter. This can be done by rubbing or shaking the cannabis material over mesh screens. Once separated from the plant, the kief powder is typically added to joints, made into edibles, or pressed into hash (we’ve covered the best ways to smoke hash in a previous article).

Dry Sift

Dry sift is the refined version of kief. It’s created by sieving kief through a graduated series of mesh screens that remove the plant matter while capturing various sizes of trichome heads. If the dry sift is then refined further with the use of static electricity to pull out all of the remaining plant material, it can end up so pure that it melts completely when dabbed—a grade of purity referred to as six-star or full-melt.

Charas

Charas aren’t common in modern dispensaries because they’re made by rubbing cannabis buds between one’s hands until the trichomes form a “stick” (which isn’t all that sanitary). However, they’re worth a mention here as a kind of solventless separation that was used in traditional hash-making cultures, especially in India.

Ice-Water Hash or Bubble Hash

Ice water hash, also known as bubble hash, is made using ice, water, filtration bags (“bubble bags”), a large bucket or bubble hash machine, and mesh screens to separate the trichomes from the raw cannabis material. After sitting in the water to chill, gentle agitation causes the hardened trichomes to separate from the plant material and fall to the bottom of the vessel where they are collected in a series of bubble bags when the bucket is drained. Once the bubble hash is collected, it must be dried before it’s dabbed or packaged for sale.

Rosin

Rosin is made by applying heat and pressure to bubble hash, dry sift, kief, or dried cannabis flower. The starting material is typically placed inside a rosin filtration bag between sheets of parchment paper and pressed between heated plates at low temperatures for a few minutes. This melts the trichomes and causes the sappy resin to flow out. 

Rosin is the solventless extract that offers the maximum purity, potency, and flavor of any solventless extract and is pure enough to be dabbed or vaped (you can learn more about dabbing in our article on how to dab for beginners).

Depending on the starting material, pressing temperature, and post-processing techniques like whipping and curing, rosin can be created with a range of different colors, consistencies, and textures:

• Colors: Almost translucent or golden yellow through to darker hues like amber 

• Consistencies: Usually sappy with a high viscosity, but can be turned into a liquid for vape carts

• Textures: Budder/badder, shatter, jam, sauce (and diamonds)

THCA and Terp Sauce

Some solventless manufacturers process rosin further using heat and pressure to separate the THCA from the (terpene) sauce. You can find these extracts in rosin vape carts or for sale as individual products. 

Are Solventless Concentrates Better?

While it often comes down to personal preference, solventless concentrates have several advantages over solvent-based cannabis extracts:

Assurance of High-Quality Ingredients

Because solventless extraction techniques don’t remove impurities from the starting material (whereas solvent extraction does), solventless extracts that have passed quality control testing were made from very clean and healthy cannabis plants.

Purity

The other main advantage of solventless cannabis extracts for consumers is the knowledge that the product is totally natural and pure. With solventless extraction, there is no risk of residual solvents being left in the final product or affecting the taste. It’s important to note, however, that modern solvent-based extracts are very clean and typically contain little to no residual solvent.

Environmental Impact

While solvent-based extracts can be purged to remove the residual solvent, extraction methods that don’t use fossil fuels (like butane, propane, and hexane) are also appealing from an environmental point of view—they don’t require petroleum oil to be mined or release any greenhouse gasses into the air during or after the extraction process.

Aromatic Integrity

The result of not using chemical agents in solventless extraction is a full-spectrum product with a strong flavor, rich aroma, and the same range of terpenes and cannabinoids that was present in the original buds (only concentrated). 

At-Home Production

Solventless extracts can be made easily, safely, and affordably at home if you have high-quality raw materials and the tools to carry out the extraction. Though many consumers prefer the convenience of purchasing extracts pre-made, setting up your own rosin press or hash washing room can be a fun experience.

Please note: If making solventless concentrates and extracts at home, be sure to abide by your state’s concentrate possession limits and don’t sell your concentrates without a license. To avoid getting too high off of homemade concentrates, it’s also essential to calculate the THC content of your concentrates as accurately as you can and start with the lowest possible dose.

The Future of Solventless

Solventless concentrates are pretty much ubiquitous now in dispensaries, but they may have potential applications in the pharmaceutical industry as well. Russo et al. (2021) noted that solventless extraction processes may be suitable for application in the future development of cannabis-based pharmaceuticals because the result is both clean and reproducible. 

Solventless Concentrates: The Bottom Line

Though the choice of cannabis products often comes down to personal preference, solventless concentrates provide the consumer with quality-assured, clean, environmentally conscious products that are perceived as more “natural” than their solvent-based counterparts. Solventless concentrates also provide a faithful replication of the chemical profile of the original strain for a potent and aromatic experience.

While solventless concentrates generally come with a higher price tag than solvent-based concentrates, many consumers consider the quality and peace of mind to be worth the price. If you’d like to find a new solventless concentrate to try or want to discuss the pros and cons of solventless vs. solvent-based concentrates with an expert, the budtenders at your local dispensary will be happy to help.