Fair point ashauler. The source of the information was the Honk Kong author. And while there are many opinions on the guy, some of which I won't argue are without merit, that aside there have been two occasions that stand out where I've witnessed plume form unexpectedly out of the blue. Both those occasions involved cooling - 1 on my own behalf / purposely, the other nature and the weather (from house & storage to destination that was approximately 30 degrees cooler than home). The "nature" occasion was with-in a 1 hour period, a cigar that had no plume was pulled out and to my surprise showed 7 -10 crystals up & down the wrapper.

In retrospect, of all you've heard over the years, I'm curious, beyond the opinions of it being perfect or extremely stable storage conditions yaddy yaddy yah, what exactly has been the explanation of what plume (the actual substance) is?

Another thing & JMHO... My experience is, it's mythical that plume represents some huge gain in strength, flavor or any other immediately discernible enhancement.

If the good Dr.'s theory is correct (about oil + moisture) and the phenomenon in general, you're probably looking at a cigar with significant oils present to begin with. Perhaps that's the explanation of the psychological belief that a pluming cigar is the Holy Grail?