Arent the cold traps also condensing hydrocarbons on the oven outlet, hence tainting flavor I was thinking of hitting mine with a 13x molecular sieve pre cold trap…mught extend vac pump oil life also.
Also, terpenes in the gas might also cause tainted terpenes.
Sub 500psi with subcooled Liquid Co2 and BOTTOM DRAIN. Pure extracted flavor fractions with no need to purge but not all Co2 designs can pull it off without some modifications. The easiest way it to get off of those rusty carbon steel tanks and upgrade to a stainless steel dewar.
Distilled terpenes and extracted terpenes are like distillate vs full spectrum.
The diversity of compounds found in extracted terpenes rings more true to the aroma and flavor of the cultivar they came from.
While the distilled terpenes will have less complexity in the compounds distilled and thus not fully embody the flavor of the cultivar.
Depends on how u extract the terpenes 
Some extraction methods are very selective and do not represent the full profile well
I keep my terpenes in the fridge with a lid after collection and didn’t think about the quicker off gassing. What’s your tek for off gassing the terps on the first day? just leave open at atmosphere?
I have had some great success isolating terpenes in a pope wiped film.
Did you try this? If so what type of material went into the vac oven? I’m use to decarbing winterized crude oil in a vac oven and the terps collected in the cold trap are gross.
Do you flush the system with inert atmosphere before starting?
As in flush the system with something like argon prior to starting the vac oven? No, I haven’t tried that. It seems though that terpenes left in the crude oil at this point aren’t as desirable or have been degraded compared to terpenes from flower.
From my research, oxidation seems to be the biggest factor in the off flavors and degradation of terpenes. Might be worth trying next chance you get
Subcritical CO2 extraction works exceedingly well. The equipment necessary is prohibitively expensive and woah-fully underproductive relative to alternative extraction methods if you plan on targeting other cannabinoids for extraction (THC/THCa) from the same material.
In my experience, you may get a layer of water that you may need to remove via a separatory funnel or by some other sorcery. The end product is quite good, if you’re willing to go to the trouble. However, these highly concentrated terpenes will not be like the terpene layer you typically see with hydrocarbon extracts. They are considerably less viscous, and represent more of a cannabis essential oil for therapeutic use, than a product to be consumed recreationally.
Is this sop anywhere on the forum? Also I’m curious if possible to sweep with compressed air since it has been through an air dryer. Would the oxygen be an issue if swept for only 5 hours and under partial vac? Any guidance or ideas welcome!