You may have seen or even sampled some flavored oils – things like pineapple or bubble gum or fruit punch. There’s a chance some of those flavorings might be terpenes, but most likely many of them are not.
Many of the fruit flavors like banana, strawberry, mint, peach, raspberry are due to the presence of chemical compounds called aldehydes or ketones. While natural fruits/plants do make these flavors, many of the individual molecules are very easy to synthesize in a chemistry lab – in fact, if you took any organic chemistry lab, you probably did a lab experiment where you made one of these fruity smelling compounds.
So what’s the difference between what you synthesize in the lab and what you find in a real raspberry? The aldehyde molecule is the same, giving a “raspberry-specific” flavor, but in a real berry, there are also lots of other various molecules that add taste, aroma and experience. The aldehyde molecule that is used for synthetic raspberry flavor is only present at very low concentrations in a real berry, which is why we don’t extract or concentrate these flavors from real berries – it’s just too expensive. This is similar to the various terpenes and other compunds in a natural cannabis flower bud that lead to the “entourage effect” of each strain’s specific flavor, aroma and “high”.
There are two reasons this relates to cannabis vape pens: taste and viscosity.
Most of the yummy terpenes “disappear” during normal CO2 oil processing and concentrating: those molecules are smaller and more likely to evaporate than the cannabinoids. A few do remain in the end, but often user’s complaint about CO2 oils is that the high doesn’t feel the same as smoking the flower– this makes sense because what’s left in the oil is mostly THC (that’s the potency people look for) and only a very small amount of the original terpenes.
Secondly, another interesting chemistry aspect about these types of concentrates (and particularly distillates, which we’ll discuss in another post) is that when you get to very high THC concentrations–above 90% or so–the oil get very thick. To the point of almost being a brittle solid and stops functioning in a normal oil cartridge. These can still be dabbed, but the convenience of a vape cartridge is lost along with all the flavors.
Processors overcome these 2 chemistry facts in a couple of ways. To address the loss of flavor, other substances can be added: things like synthetic terpenes (fairly common), natural terpenes (fairly common) or cannabis-derived terpenes (much more rare), artificial aldehydes/fruity flavors, or other artificial flavors. Additionally, the thick/solid nature of highly-concentrated extracts can be “thinned” with a solvent. This can be as simple as leaving a small amount of extra ethanol in after the cleanup step, or by adding a cutting agent of some kind. Common cutting agents include PG, PEG, VG, MCT, among others. (Propylene glycol, Polyethylene glycol, vegetable glycerin, and medium-chain triglycerides). The MCT might appear on the label as “derived from coconut oil”–which is scientifically true.
This usually leads to the question: “why should I care if it’s natural or artificial if it’s all the same molecule?”
We can probably agree that eating lots of raspberries with some aldehydes isn’t that bad for you….However, there is very little known about the safety of smoking these compounds, and in fact, recent scientific studies [1,2] suggest many of the artificial fruit and cream flavors and cutting agents convert to toxic compounds when heated to vape temperatures.
So how to know what you’re getting? Reading the label very carefully and knowing your terminology can help, as well as asking very specific questions of the budtender:
What type of extraction process was used for this? If it’s a distillate and in a liquid form, something was needed to thin it down. (CO2 concentrate is more correctly referred to as an extract).
Is it 100% cannabis-only or might there be other flavors or additives? How do they know for sure?
Sometimes it can be hard or impossible to tell – I hate to say I’ve heard some less-than-honest stories about formulations and use of language on packaging. Avitas never uses any cutting agents in our extracts and only 100% cannabis-derived terpenes that we carefully preserve for each batch.
References:  Allen, et al, 2016, Environmental Health Perspectives, 124, 6. “ Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes”
 Troutt & DiDonato, 2017, The Journal of Alternative and Complementary Medicine “Carbonyl Compounds Produced by Vaporizing Cannabis Oil Thinning Agents”