Recognizing reduction?

Opened an Aussie pair tonight from Willunga 100 – the Grenache 2005 and Shiraz/Viognier 2005. Both were screwcapped (tin liner) and both started out with a distinctive roasted aroma, that initially seemed like it could be high toast oak, but then got more like popcorn and added a smoky, minerally element. Hmm, is this reduction? It’s hard to be sure, so I tried the copper penny trick (a 1966 penny, when they were still made of copper). This involves taking a clean copper penny and swirling it briefly in the wine.

Again, we’re dealing with perception here, but the treated wine seemed to become cleaner and more fruity. Much better. And if I pour an untreated glass from the bottle, the distinction is quite clear. Side-by-side, the treated and untreated wines are different. What I suspect here to be reduction is really getting in the way of the pure fruit that’s the calling card of these appealing wines. [Update: a day later both these wines showed clear fruit when poured from the bottle, which suggests that a bix of overnight oxidation is doing the same job as the copper treatment, with the smelly mercaptans disappearing. Of course, without proper chemical analysis it's hard to say for sure - the story is, though, a consistent one.]

Willunga 100 Shiraz–Viognier 2005 McLaren Vale, Australia
Pure sweet dark fruits nose with a nice floral lift and a bit of spice. Ripe and alluring. The palate has lovely sweet raspberry and blackberry fruit with a nice balancing lemony acidity adding definition to the plump ripe fruit. It’s a really attractive, juicy, rounded red wine of real appeal. (N.b. this note was taken after the wine had a copper penny dipped in it to get rid of a burnt popcorn/acrid smoky reductive edge.) Very good+ 89/100

Willunga 100 Grenache 2005 McLaren Vale, Australia
A ripe, sweetly fruited red wine with a perfumed, slightly alcoholic red fruits nose, leading to a smooth but firmly structured palate with spicy, almost peppery red berry fruit. There’s nice balance here, if perhaps just a little too much alcoholic sweetness and heat, but it’s approaching the elegant end of the Grenache spectrum. (N.b. this note was taken after the wine had a copper penny dipped in it to get rid of a burnt popcorn/acrid smoky reductive edge.) Very good+ 88/100

[note added later: I would heartily recommend these wines - they are avialable from Liberty Wines in the UK at around £8. But then there's the reduction issue: to be honest, I didn't really care for what I'm assuming is the reduced character, and while it didn't spoil the wine irredeemably, so I wouldn't equate it to a fault such as cork taint, it's a problem.]