Expert’s Guide to Maximum Terpene Extraction

Cannabis extracts that are rich in terpenes are more flavorful, aromatic, and attractive to connoisseurs. Terpenes are the volatile compounds (present in essential oils) that give plants their flavor and fragrance. They also have therapeutic properties. If you’re serious about retailing premium extracts, terpene preservation should be a top priority.

There are several things you can do to maximize terpene retention from harvest through the extraction process and distribution. Preserving the terpenes that are already in your buds is more efficient than using separate terpene extraction methods (such as steam distillation) and reintroducing the desired terpenes later on. Following these guidelines and applying our recommended workflow for proper terpene extraction can help you create extracts that are second to none.

1. Freeze Your Cannabis Buds After Harvesting

Three factors cause cannabis terpenes to degrade: heat, light, and air. To avoid losing these aromatic compounds from your plant material before the extraction process even begins, freeze your cannabis plants right after harvest rather than hanging them in the air to dry.

According to research published in the 1990s, around 31% of terpenes are lost after 1 week of drying and 55.2% of the terpenes are lost during a 3-month drying and curing process. As soon as you’ve bucked and big-leafed your buds, freeze them in turkey bags right away rather than leaving them in a pile. Limiting this dwell time (between harvest and freezing) is critical for minimizing terpene loss.

2. Use Cold Extraction Methods

Once you’re ready to make extracts from your fresh-frozen cannabis buds, use an extraction method that keeps the buds cold. There are both solventless and solvent-based methods you can use to create terpene-rich extracts.

Solventless Extraction Methods

Solventless methods extract the terpenes and cannabinoids using mechanical processes rather than chemical ones. Cold extraction methods like ice water hash washing and dry sift separation with our proprietary Cryo-Sieve® process detach the trichomes (the resin glands) from the plant material at sub-zero temperatures. The cold temps reduce the evaporation and degradation of volatile terpenes.

Ice Water Hash

Ice water hash, or bubble hash, is made by:

  1. Submerging cannabis in a mixture of ice and water to freeze the trichomes
  2. Agitating the water to make the trichomes separate from the plant material and sink to the bottom of the vessel where they are collected in a series of mesh bags

After washing, the wet trichome heads should be freeze-dried to keep the extract cold. This extract can then be sold as-is or pressed into rosin (more on this later).

Dry Sift

Dry sift is made by agitating cannabis over a mesh screen to collect the trichomes. The pollen that falls can then be cleaned by sieving it further and/or removing the plant debris using static electricity (known as Static Tech).

When you rotate fresh-frozen cannabis at ice cream temperatures using a machine like The Original Resinator, liquid carbon dioxide, and a micron-rated screen, the trichomes remain frozen and the terpenes in the extract are better preserved.

A Note About Live Bubble Hash and Live Dry Sift

The processes we have described so far result in “live” extracts. Live extracts maintain the cannabinoid and terpene profile of the plant at the time of harvest with little to no degradation.

Because live bubble hash and live dry sift have higher terpene levels (and more flavor) than their traditionally dried and cured counterparts, they are perceived as superior and sell for a higher price in dispensaries.

Cold Pressing

You can sell high grades of bubble hash as they are. However, most extraction professionals press their bubble hash and dry sift to make rosin and sell the rosin instead. When you start with high-quality fresh-frozen plant material and wash it to make live bubble hash, you can use the hash to create cold-pressed live rosin extracts that are very rich in terpenes.

We recommend the following process:

  1. Put live (dried) bubble hash or purified live dry sift in a 25µm rosin pouch with the end folded over. Slip an additional 25µm rosin pouch over the top of the first and fold the end over to help prevent blowouts.
  2. Put the bags in a piece of folded food-grade parchment paper and place the packet between the plates of a rosin press, such as the Pikes Peak V2 rosin press by PurePressure.
  3. Bring the plates together until they’re just touching the top and bottom of the rosin pouches. Heat the plates to 130 to 170 °F and wait for around half a minute for the bubble hash to heat up.
  4. Gradually apply pressure. For live bubble hash or live dry sift, you’ll want to apply 300-900 platen PSI, which describes the pressure at the plate rather than the pressure on the gauge. The formula for calculating platen PSI is rosin press force in pounds divided by rosin pouch surface area in square inches.
  5. Press until rosin stops flowing out.
  6. Use a collection tool to transfer the rosin to a jar. Once the rosin has cooled to room temperature, seal the jar.

For maximum terpene preservation, keep the sealed jar in the fridge (up to 1 month) or in the freezer (if you plan to store it for more than 1 month). You can also “cold cure” the rosin in a cooled environment, then store it in a fridge or freezer out of direct sunlight until you’re ready to have it grammed out and packaged in airtight, light-resistant containers for distribution.

Solvent Extraction Methods

You can also create terpene-rich extracts using organic solvents. Solvents dissolve the active compounds in your cannabis material rather than separating them or causing them to flow out using a mechanical process.

Hydrocarbon Extraction

Butane and propane can be used for extracting terpenes and terpene-rich extracts. Both of these are great options if you aren’t doing solventless extraction. For best results, use The Original Resinator for biomass reduction before blasting. This makes the extraction process significantly more efficient. Afterward, remove the residual solvents under the coolest vacuum temperature possible to minimize terpene loss. If you start with fresh-frozen plant material, you can create very flavorful, terpene-rich live resin.

Supercritical Carbon Dioxide Extraction

Supercritical CO2—carbon dioxide in its supercritical fluid state—can be used for high-terpene extracts because it keeps the biomass cold throughout the extraction process. It’s important to note that this method can’t be used with fresh-frozen cannabis, it’s extremely expensive to set up, and it isn’t very cost-effective compared to solventless or hydrocarbon extraction.

Ethanol Extraction

Ethanol is a polar solvent, which means that it dissolves polar compounds such as chlorophyll, alkaloids, and terpenes more readily than its non-polar counterparts. You can get high levels of terpenes in ethanol extracts but the higher levels of chlorophyll can dilute the flavor and aroma of these terpenes. Ethanol extraction is most commonly used with hemp or very low-quality trim, when terpenes are very scarce, as a first step before the extract is cleaned up into distillate.

3. Ensure Cold Transport and Display

Preserving the terpenes in your extracts doesn’t end after the extraction process. Your customers will enjoy the most terpene-rich extracts if these remain cold until consumption. These are a few best-practices to prevent terpene degradation:

  • Use fridge or freezer trucks to transport your grammed and packaged extracts to dispensaries.
  • Ask dispensaries to display your extracts in a fridge out of direct sunlight.
  • Educate dispensaries (and customers) about the proper handling of live extracts. Ideally, customers would bring an insulated carry bag with an ice pack to take their extracts home. The extracts should then be stored in the fridge for up to 1 to 3 months or the freezer if storing for longer periods.
  • For top quality ice water hash: Before dabbing, customers should allow the container to come to room temperature (around 15 minutes) before opening it and should wipe away any moisture that has formed around the top of the jar to prevent it from falling onto the hash. The jar should then be sealed and put back into cold storage until the next use.

Maintain the Cold Chain to Maximize Terpenes

Premium cannabis strains are rich in terpenes right off the plant. Rather than use a separate terpene extraction process to enhance the flavor of your cannabis concentrates, keep your buds cold from harvest to consumption for dramatically higher terpene levels with no extra steps required.

To optimize your extraction processes, having the right equipment is a must. Contact us to learn how The Original Resinator and our cold processing bundles can help you preserve terpenes for flavorful extracts that sell at a premium price.

TJ Arnovick

Cannabis extraction expert and founder.