What Are THCA Diamonds?
THCA diamonds are crystalline structures of tetrahydrocannabinolic acid — the non-psychoactive precursor to THC. When done right, these crystals can test above 90% purity, making them one of the most potent concentrate products on the market. The process of growing them is called diamond mining, and it relies on controlled nucleation and crystal growth from a supersaturated cannabinoid solution.
What Is Jar Tech?
Jar tech is a passive THCa crystallization method that uses sealed mason jars, controlled heat (40-65C), and time (14-28 days) to separate cannabis extract into two layers: solid THCa crystals (diamonds) and liquid terpene-rich sauce. The process works by creating supersaturation: as the extract slowly purges residual solvent and the terpene fraction separates, THCa concentration exceeds its solubility limit in the remaining matrix, forcing nucleation and crystal growth. Starting material must contain at least 70% THCa for viable crystallization. Below that threshold, the solution never reaches supersaturation and no diamonds form.
The byproduct of diamond formation is terp sauce — a terpene-rich liquid that separates as THCA crystallizes out of solution. Together, diamonds and sauce represent one of the highest-value product combinations in cannabis extraction.
What You Will Need
- Glass mason jars — standard canning jars work perfectly for jar tech
- Vacuum oven — for the wax purge step
- High-quality shatter or BHO — this is your starting material
- Seed crystal — approximately 1 gram of high-quality shatter placed at the bottom of the jar
- Sharpie — for dating your jars (always label everything in the lab)
How to Make THCA Diamonds Using Jar Tech
Jar tech is the simplest diamond-growing method available to most operators. Here is the step-by-step process:
- Place your seed crystal. Drop about a gram of high-quality shatter into the bottom of a glass mason jar. This acts as the nucleation point — the crystal structure that new THCA molecules will build onto.
- Leave residual solvent. When you recover your butane extraction, leave approximately 5 pounds of residual gas in the material. This keeps the solution supersaturated, which is essential for crystal formation.
- Fill the jar halfway. You want headroom in the jar. Do not fill it to the top — the residual butane needs space as it slowly off-gasses during the crystallization process.
- Loosely screw the lid on. Leave it slightly loose to allow pressure to equalize. Write the date on the jar with a Sharpie so you can track your timeline.
- Choose your environment:
- Oven method (faster): Place the jars in an oven set to 90 degrees Fahrenheit (not Celsius — that would destroy your product). You will need to burp the jars frequently to release built-up pressure. Expect diamonds in 4-5 days.
- Cool dark place (slower): Store the jars in a cool, dark location for about one week. Same result, less babysitting.
- No vacuum needed. Unlike other purge steps, THCA diamond formation in jar tech does not require pulling a vacuum. The crystallization is driven by slow solvent evaporation and nucleation — not pressure differential.
How to Make Cannabis Wax From BHO
Wax is one of the most approachable concentrate textures to produce. The technique is straightforward: mechanical agitation at temperature.
- Whip the extract. Take your recovered BHO and whip it — like mixing a cake — for approximately 60 seconds.
- Watch the color change. This is your visual indicator. As you whip, the color will lighten dramatically. Grim describes it as adding egg to flour — the bonding changes the optical properties of the material. When you see that shift, you are done.
- The change is hard to miss. Side by side, whipped vs unwhipped material will look completely different. If you are not seeing a color change after 60 seconds, check your starting material quality and temperature.
Vacuum Oven Purge for Wax
Once your wax is whipped, it needs a proper solvent purge in the vacuum oven:
- Temperature: Set the oven to 115 degrees Fahrenheit
- Valve setup: Close the red port valve, open the vacuum valve
- Vacuum target: Pull to -28 to -30 inHg (inches of mercury)
- Duration: Standard 3-day purge — same as shatter
- Key difference from shatter: Do NOT flip the wax. Shatter gets flipped during purge; wax does not.
Pro tip for scheduling: If you are already running shatter in the oven, you can sync your wax purge to the same schedule. When you flip your shatter, bleed atmosphere into the wax tray and re-pull vacuum. You are doing everything you would do for shatter — just without the flip.
Tips for Consistent Results
- Starting material quality matters. Diamonds and wax are only as good as the BHO you start with. Run clean material through a properly maintained closed-loop extraction system.
- Temperature precision is critical. 90 degrees for diamonds, 115 degrees for wax purge. Small deviations change your product texture and timeline. Calibrate your oven.
- Burp your jars. If using the oven method for diamonds, pressure builds up from residual butane off-gassing. Failing to burp risks cracking jars — or worse.
- Label everything. Date, strain, starting weight, method. Consistency requires documentation. This is how professional SOPs are built.
- Understand your purge. Residual solvents in the final product are a safety and compliance issue. A proper 3-day vacuum purge at the correct temperature and vacuum depth is non-negotiable for any product going to market. Review our lab safety fundamentals if you are unsure about your purge protocol.
If you want to dial in your crystallization parameters with lab-tested SOPs and troubleshooting frameworks, we cover the full process in our training program at extractiontraining.com.
Ready to Build Your Own Extraction Lab?
Whether you are producing diamonds, wax, shatter, or distillate — the fundamentals of lab design, equipment selection, and SOP development determine your product quality and consistency. WKU Consulting has designed and built some of the largest and most successful extraction laboratories in the world.
Book a free consultation or join the Discord community for direct access to Grim and a network of industry professionals.
For more deep dives into cannabis chemistry, extraction SOPs, and lab design — subscribe to the WKU Consulting YouTube channel. New videos every week covering everything from distillation theory to advanced cannabinoid conversions.
Watch the full video walkthrough:
Frequently Asked Questions
How long does jar tech take to produce diamonds?
Most jar tech setups produce visible crystals within 5-7 days, but full-sized diamonds require 14-28 days at 40-65C. The slow temperature ramp (0.5-1C per day increases in the first week, then holding steady) controls nucleation rate. Faster heating produces many small crystals (sugar texture). Slower, steady heat produces fewer, larger diamonds.
What happens if starting THCa is below 70%?
The extract never reaches supersaturation. THCa remains dissolved in the terpene and cannabinoid matrix without nucleating. You end up with a homogeneous sauce that never separates into diamonds and terp sauce. For material testing at 60-70% THCa, a cold crash to -20C for 24 hours before jarring can help initiate nucleation, but yields will be low and crystals small.
Why did my jar produce sugar instead of diamonds?
Sugar forms when nucleation happens too fast across too many sites simultaneously. The three most common causes: temperature too high (above 65C triggers rapid nucleation), residual solvent above 10% (excessive butane acts as a co-solvent that suppresses crystallization until it flash-evaporates, causing crash nucleation), or mechanical agitation (moving the jars disrupts the slow crystal growth process). The fix: lower temperature to 40-50C, ensure solvent purge to 5-8% before jarring, and do not move the jars once sealed.
Can you use jar tech with ethanol extract?
Not effectively. Jar tech relies on the differential solubility of THCa in a terpene-rich matrix. Ethanol extracts are typically winterized (terpenes stripped) and contain different impurity profiles than BHO. The terpene fraction that serves as the solvent system in jar tech is absent. For ethanol-extracted material, reactor crystallization with pentane or heptane as the crystallization solvent is the appropriate method.
What is the ideal temperature for jar tech diamonds?
40-55C for the first 7 days (nucleation phase), then 55-65C for days 7-28 (growth phase). The two-phase approach works because lower temperatures favor fewer nucleation sites (bigger crystals), while slightly higher temperatures in the second phase increase molecular mobility and crystal growth rate. Never exceed 65C: above this point, terpene degradation accelerates and THCa can begin decarboxylating to THC.
