Does Ozone Kill Terpenes?

I’ve been asked many questions by clients in my five years at Willow, but none more often than “Does Ozone Kill Terpenes?”

There seems to be a lot of confusion among the industry on what Ozone does to cannabis, so let’s set the record straight. Ozone at too high of levels, or levels that are not properly controlled, is dangerous to cannabis plants. At too low of levels, it really doesn’t have much of an effect at all. Lucky for our clients, Willow has figured out the perfect ozone levels, and how to manage them. This research was done over the course of years, with cannabis product from real growers just like yourself. I’ve never once seen a test come back with any indication that terpenes had been reduced, so rest easy!

Let’s get into a little bit on how this can be the case. We know that terpenes are what provide a certain strain of cannabis its flavor, aroma, and various medicinal qualities. The aroma, however, is actually produced by terpenes that are evaporating off of the flower. The most volatile of terpenes will start to evaporate at around 70 degrees Fahrenheit. The important differentiation to make is that an evaporated terpene may make that jar of cannabis smell great when you open it, but those terpenes no longer have any medicinal value for a client, as they have entered into their gaseous state, and are not readily available for combustion/vaporization.

Willow does not use high enough levels of ozone to penetrate oils (terpenes). What actually happens during our process is that ozone clings to the outside of these terpenes and forms a sort of bubble around them. This effectively stops the terpenes from evaporating while in the process, and for a short time afterwards as the ozone off-gases from the flower for 5-7 days. The biggest concern of growers once product has finished its decontamination cycle is that the smell is a little bit different than they remember. This is true. The product will smell different immediately after the Willow process for two reasons:

One – There is residual ozone that needs to be off-gassed, which has its own unique smell.

Two – The terpenes are not evaporating at the rate they used to, which in turn doesn’t produce as much of an odor.

But this is temporary! WillowPure systems use ozone because it quickly degrades back to oxygen, so any residual smell won’t stick around. And when growers follow our simple post-care process (burping the bags), the product always goes back to the way it was before treatment. If you have any questions, feel free to email me at, I’m happy to help.

Steve Ottman, Head of Product