The day I learned about “petrol” notes in wine was a pretty funny one.
Years ago, I was in wine class (mandatory for staff if you wanted to be / were a server) and our wine director described a wine like:
“Eating a green apple at a gas station while the road is being paved.”
Very creative.
This is where we talked about petrol notes in wine and how it’s a key indicator that you’re likely drinking Riesling. Other grapes (such as Sauvignon Blanc, Chardonnay and Cabernet Sauvignon) can show this characteristic too, just not quite as strongly.
The breakdown of certain natural “precursors” during the aging process results in higher levels of TDN (1, 1, 6, -trimethyl-1,2-dihydronapthalene, if you really love chemistry), the chemical compound that smells like petrol, gasoline, and even rubber (sometimes, it reminds me of asphalt).
Factors that increase these precursors in grapes, according to winemaker, Adam Eggins and wine writer, Joe Roberts are:
Ripe grapes
High sun exposure
Water stress
High acid
So, these conditions, in addition to a longer period of aging time, a low pH wine (meaning higher acid) and a warmer aging temperature (to increase the rate of the chemical breakdown) is a recipe for TDN.
Riesling is RESILIENT – it grows despite harsh conditions. In Germany, where Riesling is king, a lot of the vineyards are on INCREDIBLY steep mountainsides where it is very cold and hard to retain water. High sun exposure is still attainable due to reflections off the rivers (how crazy is that?). And, of course, high acidity is achieved because these severe growing conditions do make it difficult for grapes to ripen fully.
This used to be considered a flaw in wine, hands down…And if there’s too much TDN, true, it’s not awesome. But nowadays, there seems to be a pretty epic debate about whether or not it’s a flaw with fair arguments on both sides. Some argue that it is not the most desirable tasting note, while others argue it is simply part of the natural aging process.
I personally don’t mind it too much! Besides it being an unexpected / interesting surprise, it really helps with your blind tasting game. The more exposure you get to it, the better you’ll be… you’ll be picking out Riesling every time.
Still on a Riesling kick? Check out how to decipher Riesling wine labels at the store!
