Barolo-Missing The Road Tar/Petrol ?

WINE TALK
1

Years back I used to find and enjoy both road tar and a hint of petrol in my Barolos. For whatever reason, I don’t seem to find it any more and have not for some time. Is it just me, or the style of the producers I have been drinking, such as G. Conterno, A Conterno, G Mascarello, Brovia, Spinetta ? Curious whether others miss it too or where I can find it. Lots of discussion here on petrol in Riesling which I don’t particularly enjoy, but have not seen any discussion of this with respect to Barolo.

2

Along these lines, is there any relationship between the ‘tar’ aromas in Nebbiolo and petrol in Riesling caused by TDN? A few folks have stated a correlation both between warmth of vintage as well as bottle aging with the strength of the tar aroma in Nebbiolo. Petrol has a similar pattern in Riesling with warm regions showing very extreme petrol character. Aging also brings out the petrol.

To me the tar in Nebbiolo seems much closer to the petrol in Riesling than something like a reduced sulfide aromas such as rubber tire. Circumstantial evidence, definitely, but surely someone has looked into Nebbiolo chemistry, right?

3

I always thought that road tar (and the related, burnt rubber) were products of brett.

I doubt the tar/rubber, etc. were the result of anything really desirable. Just like the Burgundy “barnyard”, some people liked it, but when winemaking became more hygenic, it disappeared from the scene.

4

None of the aromatic metabolites of Brettanomyces (principally 4-EP, 4-EG, and isovaleric acid) smell like either road tar or burnt rubber. Burnt rubber is most often a reductive sulfur compound. I don’t know what’s behind the tar aroma, but it’s not Brett.

4-EP = Band-aids®, antiseptic, and horse stable

4-EG = smoked bacon, spice, or cloves

Isovaleric acid = sweaty saddle blankets, cheese, rancidity

5

this link and others disagree with you, Bob.

6

The odours caused by the development of this yeast are varied : animal (musk, venison etc), stable, horse sweat, leather, pharmaceutical, ink, gouache, plastic, burnt rubber.

this site even has a picture of some guy with a dixie flag [highfive.gif] on his hotrod in the act. http://www.apps.fst.vt.edu/extension/enology/downloads/Delteil_Noblesse_guidelines_dec_2010.pdf

these link and others disagree with you, Bob.

And, this site has a “wine defect kit” that ascribes “tar” to brett…

also http://www.corkbuzz.com/1236/general/brett-complexity-or-defect/

Frankly, I don’t know enough to opine. I’ve certainly always thought of burnt rubber as a sign of brett…and know certain wineries’ wines that are frequent examples. On the tar track, I know nothing, admittedly.

7

Stuart,

If you want to see who can post the most links to support his postion, I’m game. But no fair double posting!

neener

Cheers,
Bob

8

Been trying to figure out how to delete the first of the pair…sorry. But, saying things twice does work in some cases… pileon

9

I’m with Bob here–as long as this discussion doesn’t go the direction of varietal vs. variety! [wink.gif]

I follow the Jamie Goode school of thought: Brett is not the universal cause of all non-fruit, non-pyrazine aromas. Volatile reduced sulfur compounds are a huge contributor to funky wine aromas usually related to primary fermentation issues. Trimethyldihydronaphthalene (TDN) in Riesling seems to be related precursors found in unusually high concentrations in Riesling.

Brett has a very wide range of volatile compounds that can be produced in differing concentrations depending on its strain, precursors and growth conditions. Reduced sulfur compounds may also be a byproduct of oxygen starved in-bottle fermentation. But it strikes me as extremely unlikely that ‘tar’ in Nebbiolo is from Brett. I’ve had Bretty Nebbiolo where the usual farmy, cheesy qualities are present. But most Nebbiolo has some tar character in my experiences, even very modern, clean styles. Why would this appear regularly in the absence of other more common Brett characteristics?

10

I’m also with Bob on this. I’ve had a number of wines with a burnt rubber smell that was absolutely caused by reductive sulfur compounds, and I’ve had no reason to believe there was any brett involved. Tar is something different and I don’t know as much about that character in wine, but again, I’ve had wines with some tar aromatics that I’m reasonably sure had no brett in them. I don’t know whether TDN is involved in any way with tar aromas in Nebbiolo, but the only wines I recall having with distinct “petrol” aromas are Riesling and Grenache Blanc.

11

Ok, I’m convinced, I’m with Bob on this, too…now that I’ve read your anecdotes. [help.gif]

12

For another view, I have also smelled tar in Nebbiolo that seems to be quite clean, even some that was made in fairly modern (in the sense of being clean, anyway; not trying to define or debate this term in Piemonte) facilities. The first thing I always smell when there is brettanomyces is smoke, and it’s a specific type of smoky aroma that is unlike the smoke I get from oak or anything else. I have definitely smelled tar without smoke, many times.

13

Burnt rubber is a mercaptan, according to Jamie Goode’s book and everything else I’ve ever heard and read – ergo, a reduced sulfur compound. To me, tar seems to be close as an aroma, but perhaps it isn’t chemically. (Burnt rubber seems closer to burnt coffee and burnt toast to me.)

I don’t normally think of burnt rubber popping up much in nebbiolo, though tar certainly does.

What kind of “petrol” are you talking about in riesling? There is often the sulfur scent in young wines, but the classic diesel aroma of middle-aged and older rieslings is a somewhat different, presumably more evolved sulfur – very reminiscent of the streets of most European cities before they switched to low-sulfur diesel fuels. Petrol/gasoline has a different aroma profile, and I don’t think of it as being so sulfuric.

14

I’m not an organic chemist, but I’m almost certain that TDN (the source of the classic ‘petrol’ aroma in Riesling) is not a sulfur compound.

As for what the classic ‘petrol’ aroma smells like, it’s more like kerosene than anything else to me. Diesel is reasonably close. But I have never smelled anything in Riesling that was at all similar to gasoline.

15

I agree. It’s much more diesel than gasoline. But diesel I associate with sulfur.

16

Can’t imagine why. Diesel doesn’t have a sulfurous smell.

Now, if you’re talking about the fumes from a diesel engine, the combustion product of diesel fuel, that’s a different story - but that’s not the ‘petrol’ aroma of Riesling. Not at all.

17

Having spent time in Europe in the 60s and 70s, it’s hard not to associate diesel with sulfur.

18

So, I guess we really don’t have an “answer” on the “tar” issue…just opinions? At least there are opinions all over the spectrum of brett-sulphur out there. I have no answer myself, obviously. Not even anecdotal.

19

I have always attributed the road tar/resin characteristic to the Slavonian Oak. In my mind, one of the reasons it may have “disappeared” is that so many (in the OP) of the producers have moved away from traditional methods and have moved to more modern ones, namely, barrique. There’s a lot of really great Eastern European oak (and various trees) being used in the Langhe these days, many to great effect, but then I’m partial as I prefer more traditionally styled wines.

I take comfort in the fact that many (formerly converted) are now eschewing barrique and returning to more traditional wood treatments.

20

Of Robert’s original list of producers that got this discussion underway – G. Conterno, A Conterno, G Mascarello, Brovia, Spinetta – it’s mix of approaches to oak. G. Conterno and G. Mascarello use no barrique, and A. Conterno claims not to. Brovia started using barrique, I believe (someone will have to check me on that) and Spinetta is on the extreme end of the modern scale.