Anthony Road Rules

8 May 2009
By Tom Mansell

Anthony Road Semi-Dry Riesling 2007
Appellation: Finger Lakes
Variety: Riesling
ABV: 12.3%
RS: 1.9%
Price Point $16
Notes:
Nose: lime and pineapple on the nose, but the first thing I notice is our old friend petrol*, which in this case adds some nice complexity to an otherwise crisp and fruity nose.
Palate: rich {mouthfeel} with refreshing acidity. Very nice on the palate. The sweetness and overall body give a lemon chiffon feel. Really enjoyable.

Rating: corkcorkcorkhalfcork

I have not yet been to Anthony Road, but I have heard winemaker Johannes Reinhardt described as “dreamy”. So, that’s good for the ladies. If his other wines are just as dreamy, then they are doing a fine job out there. Riesling month is off to a delicious start!


1,1,6-trimethyl-1,2-dihydronaphthalene, or TDN to the syllabically challenged.

*Science!
The petrol component, as we discussed in the riesling ice wine bonanza, usually shows up in riesling wines after a bit of aging. But this wine is a 2007? What’s going on? Let’s look into the origins of the aroma compound.

The molecule in question is 1,1,6-trimethyl-1,2-dihydronaphthalene, which is thankfully abbreviated to TDN. TDN’s aromas can be described as kerosene, burned rubber, or the much nicer French term goût petrol. Nothing with a circumflex (château, l’Hôpital’s rule, etc.) can be that bad, right? While it tends to add a bit of complexity to a fruity bouquet increasing amounts of this compound can make it an off-aroma.

It’s thought that TDN arises from the breakdown of carotenoids in wine. What are carotenoids? Carotenoids are color compounds. In the fall, when chlorophyll in trees breaks down, what’s left are the carotenoids, yellow, orange, red, etc. They mostly serve to protect chlorophyll by absorbing damaging wavelengths of sunlight. As such, carotenoids are usually higher in grapes grown in hot regions with lots of sun. Carotenoid concentration can affect the emergence of TDN as wine ages. Also, carotenoids are produced until veraison (i.e. the beginning of ripening), then degraded during maturation. So (1) the more concentrated your carotenoids (e.g., hot, dry year), and (2) the longer your maturation time, the more carotenoid breakdown products you’ll end up with in your wine.

2007 was a hot, dry year in the Finger Lakes. As such, many producers produced very ripe grapes, and let them hang for quite a while for maximum ripeness. In riesling terms, this could be a recipe for TDN, if not now then in a few years. On a side note, not all carotenoid breakdown products are bad. β-damascenone (canned apple), β-ionone, and the aptly named Riesling acetal all are the result of carotenoid breakdown. I’ll be tasting quite a few 2007s during “May is riesling month”, so stay tuned!

If you want some real science, check out this quote from an excellent and very detailed review of the subject of carotenoid breakdown by Maria Manuela Mendes-Pinto in Archives of Biochemistry and Biophysics (2009) which was the source for much of the above information. This is the kind of stuff I love.

It is important to take into consideration that the model systems studied for thermal degradation of β-carotene require extreme temperature over a long period of time, sometimes in the presence of organic solvents such as ethanol and benzene and . Although these conditions are not representative of the natural conditions that can contribute to the degradation of carotenoids and norisoprenoids formation, they are valid studies because they can be indicators of the naturally occurring reactions. The formation of TDN and Riesling acetal by acid hydrolysis of megastigmane structures as intermediates has been proposed by Winterhalter in 1991. The existence of multiple possible precursors for TDN, vitispirane and also of β-damascenone, was observed in heated juice of Riesling grapes; the glycosylated forms were hydrolysed to release the corresponding aroma norisoprenoids. In Riesling wines, TDN, vitispirane and Riesling acetal were formed in high concentrations by acid hydrolysis of the glycosylated precursors. While the precursor of β-damasenone has already been suggested (megastigma-6,7-dien-3,5,9-triol) the precursors of TDN and Riesling acetal were proposed later; the glycosylated form of 2,6,10,10-tetramethyl-1-oxaspiro[4.5]dec-6-ene-2,8-diol identified in wines was considered as a natural precursor of TDN after acid hydrolysis, while 1,4-dihydroxy-7,8-dihydro-β-ionone was considered as the precursor of Riesling acetal. This work also provided evidence of multiple precursors of TDN as previously suggested in related work with the same Riesling wine (P. Winterhalter, M.A. Sefton and P.J. Williams, Am. J. Enol. Vitic. 41 (1990), pp. 277–283).[74].

I guess it makes more sense with the figures.

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6 Responses to Anthony Road Rules

  1. Don Giovanni on 9 May 2009 at 12:00 am

    Nice job…

    A few more things to think about…

    Fermentation temperature, the specific clone of the vine, low yields, skin contact, time of harvest,I.E. Late Harvest, etc… irrigation or a wet growing season in a dry year, yes, then a wet year in a hot year… the amplitude of heat and sun differential during the growing season, transporting the grapes to the crush pad…the time the grapes go from vine to crush…so many different variables…yeast and the metabolic changes at different temperatures…many pathways…the % of acids to alc ratio…tannin density all these and many more factors can be the cause of goût petrol :::Cheers !!!

  2. Peter on 12 May 2009 at 10:24 am

    Tom, Nice post on our wine, thanks for breaking it down for us. I have been following this site ever since Lenn mentioned it a little while ago and you have found the perfect niche in this wine blogosphere. Tom, I would like to invite you to the winery this Saturday the 16th as Johannes and I will be hosting an open cellar event. We will be pouring (last count) about 12 Rieslings from past , present and future. This could be the perfect opportunity to really get to know our Rieslings. From Dry to TBA we will have it all available to taste. If feeling confident we challenge you to the Tierce Blind Tasting Challenge. How well can you palate really decipher between vintages. Peter Becraft/Associate Winemaker

  3. [...] WD-40 smells like. It’s part gasoline, part floral sweetness) Part of that may not be all TDN, it may be more sweaty/grapefruity. Palate: nice acid balance. Also limey on the palate, like [...]

  4. [...] a comment on the blog from Peter Becraft, associate winemaker at Anthony Road Winery in response to my review of their 2007 Semi-Dry Riesling. It invited me to their Open Cellar Tasting event, where they were pouring around a dozen rieslings [...]

  5. anonymous on 7 December 2009 at 11:40 am

    A small point of clarification, the correct structure for TDN can be found here:

    http://webbook.nist.gov/cgi/cbook.cgi?ID=C30364386&Units=SI&Mask=2000

  6. [...] by my colleague Tom Mansell, a warning sign that the wines will age more quickly than usual. (This entire short piece will do more to educate you on riesling in five minutes than most of what you can read in long [...]

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