While out on one of my not-frequent-enough dusty bottle hunts, I yesterday came across some 30+ year old Strega (at least pre-barcode packaging). Striking as the yellow color is in this liqueur, in this case it was strikingly absent - in several bottles to the point of being completely clear. At first I supposed that this was simply a fading due to sunlight (saffron, the source of its hue, is a notoriously fragile and unstable colorant), however a securely boxed bottle proved to have the same lack of yellow color so light can't be the only culprit here.
At $17 a dust-covered-whack, I was willing to give a bottle a try and happily the color seemed to be the only thing that had faded (At least to my memory, I don't have a fresh bottle handy to do a direct comparison yet).
My curious question is this: Has anyone seen/experienced this before?
My deeper question is: What outward signs of age have been known in various liquors, such as color fading/darkening that can suggest age without any accompanying off-taste. Are there any outward signs of age might be used as markers for spoilage or off-taste in any particular liquor? Obviously neck-creep is a biggie as far as old bottles go (and does that increased airspace tend to affect taste?).
I curious, partially as an avid dusty bottle digger, but also its always come to my mind when discussing subjects like the Campari color change-over and whether age, as well as colorant, played any role in one tasting different from the other.
I definitely think aging can make some difference in the taste and appearance of herbal spirits. How the spirits are stored (temperature, exposure to the light, etc.), how long the spirits are stored, alcoholic proof, the nature of the flavoring agents (certain chemicals are more suceptible to certain kinds of changes over time), and packaging will all make a difference, of course. Proof can be especially important. In general, we would expect something like 80 proof Strega or 41-50 proof Campari will show more effects of aging than, say, 110 proof Green Chartreuse.
My personal belief is that much of the outcry over the "changed flavor" of Campari when they took out the (flavorless) carmine has to do with the effects of aging and the fact that the carmine-containing bottles of Campari we have over here are likely to be quite a bit older than the ones without. I note that there is no such oucry in Italy, where Campari is consumed much more ubiquitously and the supply has always been reliably fresh (all the moreso when one considers that Campari is considered an inviolate national treasure and the fact that Italians love nothing more than righteous indignation).