Drying: Microwave vacuum (Enwave's "Terpene Max") vs. Aw (Aroya's "Dry Module")?

[Ralf]

Let’s talk about the pros/cons of microwave vacuum drying and traditional hang drying with real-time water activity estimation with AI machine learning. If you’re not interested in pushing the envelope for drying, data collection, and analytics, this thread probably isn’t for you.

Needless to say, I have serious doubts about microwave vacuum drying for AAA flowers when compared to ideal slow-hang drying conditions (day 1-3 @ 68’F/48% RH & day 4+ @ 64’F/58%) using Aryora’s “Dry Module” for real-time water activity estimation with AI machine learning.

There are a couple of threads on microwave vacuum drying on this site. Neither got traction, and they don’t provide actionable information: Microwave Drying of CBD Hemp & "How to make a microwave vacuum dryer with turntable"

I just read a newly released academic journal sourced and written book from CRC Press titled, Handbook of Cannabis Production in Controlled Environments. (Find my book review here). Chapter 10, Harvest and Post-Harvest, briefly discusses microwave vacuum drying and offers a comparision of various drying methods based on terpene loss and cost (but they surely don’t like the Oxford comma, lol ):

10.7.10 Microwave Vacuum Drying
Microwave vacuum drying removes moisture using microwave radiation, low temperature and low pressure. The low temperatures prevent the loss of volatiles, while the microwave radion evaporates moisture through the inflorescence. The result is a very fast drying process (sometimes less than 45 minutes) and good preservation of the original chemistry. EnWave Technologies (www.enwave.net) offers an industrial-scale drying system using microwave vacuum technology. EnWave claims less than 5% loss of THC and less than 35% less of terpene content for cannabis.

EnWave makes bold claims about their Terpene Max microwave vacuum dryer regarding reduced terpene and cannabinoid losses vs. hang drying. Enwave’s system increases flower surface temperatures to 102’F for around 50 minutes. Compared to 60-68’F air temperature for room drying for 7-10+ days, microwave vacuum drying seems bound to volatilize the most prized light terpenes (monoterpenes) due to its heat. But the proof will be in the pudding! I would also imagine the 20 torr vacuum pressure would puff out the bracts, giving the flower an odd appearance. I attached their sell sheet to the their third post.

I attached the Aroya’s “Cananbis Dry Cure Modle Story Board” and “Cannabis (isotherm) Validation” to the third post.

The initial cost of Aroya’s Dry Module is around $14,000 for the first six months, followed by a $1,000 monthly subscription fee for a minimum of 6 months. The total for the first year is about $27,000.

[Ralf]

I will find out the price for the Terpene Max tomorrow. I think we may rent their small unit just to see it in operation - that’s their way of giving customers a trial period. That way, I can do a small-scale comparison of the dried flower using that system to the dried flower under optimal slow-hang drying conditions with water activty tracking using Aroya’s AQUALAB 3 water activity meter (about $12,000).

Is anyone aware of a professional cannabis sensory panel?

I’m hoping to find a group of folks trained in organoleptics for cannabis flower sensory evaluation. Like can be found for wine and beer that use tetrad or triangle testing. I want to find a group I could send samples to for blind organoleptic analysis. I realize there are issues with sensory testing, especially triangle, but there must be groups doing it well.

Before someone says, “just send it to a lab,” the best cannabis labs like Anresco, which offers R&D testing for 27 different terpeneoids cannot replace high-quality organoleptic analysis. Blind sensory evaluation by a panel of trained professionals is the best way to achieve my goal of comparing microwave vacuum drying to slow-hang drying with real-time water activity analysis.

[Ralf]

EnWave White Paper - Maximizing Terpene Retention with REV - Cannabis.pdf (1.7 MB)

Aroya Cannabis Dry Cure Module Story Board.pdf (1.6 MB)

Aroya Cannabis (isotherm) Validation.pdf (273.9 KB)

[cyclopath]

@Ralf

but there must be groups doing it well.

Maybe.

I would assume that most folks are doing this in-house, and nowhere near as scientifically as you’re proposing.

Certainly seems like a fun niche to try and fill.

Who wants in on Emerald Triangle Organoleptics?

[Ralf]

I’m glad to have you in the conversation.

“Emerald Triangle Organoleptics” has a nice ring to it! I bet that could be a lucrative venture.

I think you’re in Oregon, maybe Portland? You should contact Jermey Plumb, co-founder of PRŪF and founder of Oregon’s Cultivation Classic cannabis competition. The Cultivation Classic uses double-blind sensory panel testing for organoleptic comparisons. Jeremy is well versed in sensory science, taking cues from the beer world.

I plan to contact Jermey to see if he can impanel his judges for paid sensory analysis. He’s the only person I can think of that may be able to do what I seek.

I could imagine a cannabis version of Cicerone certification, where ‘off flavors’ for beer would be analogous, for example, to ‘grassy/hay’ aroma and what I call ‘soil’ flavor (from foliar microbial IPM products I assume) for cannabis.

I’m a level two certified Cicercone, and if I had the time I’d go for level three certification. I think this model should be applied to cannabis (flower and concentrates) as well.

[Ralf]

Here’s an interesting paper. They don’t disucss low temp micorwave vacuum drying, but they do discuss microwave drying (high temp):

Post-Harvest Operations to Generate High-Quality Medicinal Cannabis Products:...

Plus this oldy, finding up to a 50%-ish loss of monoterpenes when hang dried at room temperature:

The volatile oil composition of fresh and air-dried buds of Cannabis sativa -...

[cyclopath]

I’m down in Eugene. I was one of the louder voices insisting during the OLCC rule making process that we needed to be allowed to do Organoleptics: In House QC?

the team I currently work with are ALL critics (and everybody enjoys doing their homework).

[Ralf]

Thanks for the link!

[Ralf]

Here’s the response from a scientist after I asked for her thoughts on microwave vacuum drying of cannabis. It seems to be the nail in the microwave oven for me. I didn’t even consider how microwave vacuum drying may affect the enzymatic process, which occurs over days while drying.

Microwave does not allow for breakdown in carbohydrates or chlorophyll and leads to a rough, coughy smoke. If craft cannabis is the goal, I would need to see the methods for the terpene study as I do not know what aW they are reporting for hang drying.