What creates that ozone smell in wine?

[Michael M]

Think midwest thunderstorms, lightning slashing, pounding rain. Besides damp concrete and earth, the other smell I associate with this is ozone, created by lightning. I'm not sure how else to describe it, except if you're not from a thunderstorm-prone area, there are "fresh air" products from places like Sharper Image, et al., that produce ozone. It smells fresh, clean, rainy, happy. For science geeks, it's O3 vs. earth's atmosphere's typical O2.

But my question is - why do I smell it in some wines? It's not a bad thing at all to me, usually coming across along with earthy smells. Think deep forest after a rain. I think I get it mostly in reds, especially the earthier ones like Pinot Noir or Sangiovese.

Anyone know?

[Rebel Rose]

So, you mean, supercharged fresh air, and not the sulfurous pre-lightning smell, right? Hmm. I have no idea. I'll ask Dover Dan. Maybe someone here can enlighten us both. Our winery has a grenache blend we just bottled that I describe as 'forest aromas of wild strawberry, oak, pine, humus and violets' and it gives me that same experience. It's also a lighter spicy red.

Edited to say: I've always said red wine is good for atmosphere!

Edited September 18, 2004 by DoverCanyon (log)

[Michael M]

Right, I should have been specific. I don't mean hell and brimstones sulfuric ozone, but the "supercharged fresh air" smell you're referring to.

[magnolia]

My sources have provided to possible explanations: 1) vine leaves contain ozone, and ozone generators are sometimes used to treat oak barrels that have been infected with Brettanomyces (aka "Brett", which is the yeast that gives red wine the distinctive 'barnyardy' aroma). However the ozone used for for sterilisation (O3) quickly reverts to molecular oxygen (O2), so there's probably something a bit more complicated going on if this is the source. 2) Alternatively, the 'thunderstorm' ozone aroma of ozone is similar to that of a freshly struck match before the scent of burning - so it may be the sulphur (also used to treat barrels).

[Rebel Rose]

. . . ozone generators are sometimes used to treat oak barrels . . .

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Mmm, except we use an ozenator on all our barrels regularly, and only one wine right now has that "fresh forest after a rain" scent. After talking with two winemakers yesterday, the mini-consensus is that it's simply one of the aromas present in certain varietals.

[Michael M]

Thanks both for these replies. I'm confused about ozone being present in leaves, since ozone is a gas. On leaves?

But the ozone generators make some sense, though not if you're only getting it with one wine.

I often get this smell, but have never heard it as a descriptor. Anyone else notice this, too?