Are Petrol Notes In Aged Riesling A Fault? (Thoughts On A Clare Valley Master-class)

Vinted on May 22, 2012 binned in commentary, on the road

“I’m going to be honest with you, that smells like pure gasoline.”

We’re not talking about Sex Panther here, people – but we are talking about something that is quite pungent… in a good way…

Riesling. Specifically, a factor that many consider to mark some of the best aged Riesling wines on the planet: an aroma reminiscent of petrol, or vinyl, or rubber. It’s a marker that I’ve encountered in many a fine aged Riesling, including one that has come from arguably the best vintage of the 20th century from arguably world’s best producer of the stuff.

During my recent jaunt to Australia, the group of East Coast Sommeliers with whom I was traveling was treated to an in-vineyard pruning lesson followed by an in-office Clare Valley Riesling Masterclass, headed by Taylor Wines’ Chief Winemaker Adam Eggins. [ Editor’s note: if you enjoy the wines of Taylors  (known as Wakefield in the U.S.), then you should silently hope that none of the grapes for future vintages hail from the vines that we mauled that day ]. Like most good Aussies, Eggins is quick-witted, opinionated, and not afraid to hide those opinions even when actually he’s trying to hide them. But even Eggins didn’t quite reveal his hand when he shared with us a French report on the Riesling/petrol phenomenon (shared below, emphasis mine):

With time, Riesling wines tend to acquire a petrol note (goût petrol in French) which is sometimes described with associations to kerosene, lubricant or rubber. While an integral part of the aroma profile of mature Riesling and sought after by many experienced drinkers, it may be off-putting to those unaccustomed to it, and those who primarily seek young and fruity aromas in their wine. …the German Wine Institute has gone so far as to omit the mentioning of “petrol” as a possible aroma on their German-language Wine Aroma Wheel, which is supposed to be specially adapted to German wines, and despite the fact that professor Ann C. Noble had included petrol in her original version of the wheel.”

Another way of saying that, is that Riesling’s petrol aroma is a fault.

But is it, really?

The answer, I think, is an emphatic NO

The French report goes on to mention the specific compound responsible for this hint of gasoline in older Riesling wines, and the specific factors that contribute to its development:

“The petrol note is considered to be caused by the compound 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), which during the aging process is created from carotenoid precursors by acid hydrolysis. The initial concentration of precursors in the wine determines the wine’s potential to develop TDN and petrol notes over time. From what is known of the production of carotenoids in grapes, factors that are likely to increase the TDN potential are:

  • Ripe grapes, i.e., low yields and late harvest
  • High sun exposure
  • Water stress, which is most likely in regions which do not practice irrigation, and there primarily in certain dry vineyard sites in hot and dry years
  • High acid content”

Another way of saying that, is that all the elements that make grapes prime candidates for producing premium, long-lived Riesling wines also significantly increase the chances that those wines will one day smell like gasoline.

And so I’d argue that the hint of petrol is not a fault, because it is a natural by-product of the very conditions that contribute to the greatest Rieslings other great attributes: robust and complex fruitiness, concentration with a thread of stony minerality, and a finely-grained acidic backbone that contributes to some of the longest aging potentials – maybe the longest – of any fine wine.

If the hint of petrol is too pungent or too aggressive, than that Riesling does happen to have a fault of sorts; but that fault isn’t the presence of TDN – it’s the wine being out of balance (which would be a detriment if any one aspect, like alcohol, or fruitiness, dominated).

So, sorry about this Frenchies, but TDN is not a fault just because some people prefer fruit and only fruit when partaking of their Riesling sniffing.

Oh… and two of my favorite Riesling examples from the Clare Valley during that Masterclass – Kilikanoon’s Mort’s Reserve (of which we tasted the 2011 and 2005 releases) and Jim Barry’s “The Florita” (both the 2011 and 2008 versions were sampled) – were marked by their racy acidity, fabulous textural aspects, tightly wound lime fruit and… waaaaaiiiiiit for it… beguiling nutty, honeyed and PETROL-like aromas in the older vintages.

Go figure.

Cheers!

20

 

 

    Comments

  • 1WineDude


    Thanks for those links, Todd! I could certainly be convinced that if the petrol note is really prevalent in younger wines that it could be a flaw – and talking TDN here, not reduction (which I would definitely consider flawed if it isn’t the kind that will blow off after a few minutes in the glass)…

  • @UCBeau


    Nice post Joe, hopefully it generates some discussion on this phenomenon. I like finding that subtle petrol-y note in older rieslings and gruners, but have a few friends who find any whiff to be almost unbearable. Guess in that way it's a bit like brett and volatile acidity.

    • 1WineDude


      @UCBeau – thanks. It has, but it has all been on FB and twitter rather than here (such is the way of things now, I suppose!). I think it’s a bit different from Brett and VA, though – those can theoretically be controlled (Brett can be minimized though it is of course expensive to do that, and VA can be monitored and certain steps taken to help minimize that also).

  • Seth Nichols


    Great post. I recently tried a German Riesling, a 2005 R Fusion, from the Nahe region. It had some nice petrol on the nose, in fact, the whole kitchen smelled like petrol after I opened the bottle! It was a nice glass of wine.

    • 1WineDude


      Thanks, Seth. Glad to hear you went Nahe, I think that is generally an under-appreciated region for Riesling. Cheers!

  • SUAMW


    TDN is not unique to Riesling. I've encountered it in aged Viognier. Don't have the citation on hand, but had found some article that supported the idea that TDN is not exclusive to Riesling.

    • 1WineDude


      SUAMW – I think you are correct, and I've heard it can impact Chardonnay as well. It would surprise me if it was only limited to Riesling, actually.

      • SUAMW


        You're right. When you consider that different cultivars are still the same species, there no reason why TDN should not be ubiquitous in wines from all types of grapes.
        I've also come across TDN in young Monterey Riesling – I forget if it was from a short, cool year with lots of shatter or a hot one…..
        I suppose that if you (counter-intuitively) made a Riesling with oxidative (to an extent) methods, you might bring out a strong TDN note in a young Riesling.

        • 1WineDude


          SUAMW – I guess the question then would be, is that a fault because it’s noticeable when it is young? I’m inclined to say yes, but more a fault of overall balance rather than a fault of its presence.

          • SUAMW


            Well, that's a matter of asking if the growing and vinnifying methods are allowing the DNA and site to express themselves. True, it's a matter of mode de l'époque. These Monterey Rieslings struck me like that new car leather smell – if you like that, it's not a fault (after all, pepper, bandaid, raw game are desirable traits…) It's also like the issue of pyrazines: Some can't stand them but wines that show the bell peppery edge at 2-3 years old, can evolve in bottle and that bell pepper becomes a luscious black currant. In that sense, one has to ask what happens with time with high-TDN young Rieslings…. Then we have a different landscape and context in which to ask that question. Plus the question what is a greater/finer/better wine: one that has one sort of appeal right out of the cellar but does not evolve into something more sublime OR one that has some edginess to it in its youth and only blossoms after some cellaring……
            Next time you're on the left coast, drop by and we'll have a few, talk and I'll show you how to play a *REAL* guitar…..

            • 1WineDude


              SUAMW – by real guitar you mean 6 string bass, right?!?? ;-)

              • SUAMW


                NO, but a real bass has 4 strings, stands upright, has f-holes and no frets. …. ;)

              • 1WineDude


                Yeah well some of us play those too…

              • SUAMW


                Yah, well, can you bow it like in that Primus video? huh?….

              • 1WineDude


                Bow, yes; like Les, no! :)

  • SUAMW


    NO, but a real bass has 4 strings, stands upright, has f-holes and no frets. …. ;)

  • gdfo


    It is a matter of education, really. Older well preserved riesling do produce some 'petrol' notes. So?

    If the wine is slightly chilled and it is allowed to breathe it changes dramatically.

    • 1WineDude


      gdfo – Amen. I might actually be at the point where, just as a wine lover / geek, I am disappointed when I don't find petrol in old Riesling…

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