Don’t worry – I am not advocating as part of the Revolution that we start watering down our fuel tanks with a blend of Super Unleaded and J.J Prüm ‘96. What I am in fact referring to are the aromas that are often found in Riesling which smell unmistakably like petrol.
Perhaps I should first begin by defining what I mean by “petrol”.
It has long been observed that top quality mature Rieslings – that is, those with around five or more years in the bottle – develop what some like to refer to as a petrol-like aroma. Surprisingly, these aromas are highly prized amongst Riesling aficionados as contributing to the classic “Riesling nose”, although many prefer to describe them as having a “mineral”, “chalky” or “iodine” character rather than petrol which sounds degrading.
These subtle and complex aromas should be distinguished from the fierce and full-on petrol aromas which can often dominate young Rieslings, especially those which have been produced in hotter regions with short growing seasons, such as Australia.
It is generally considered that these aromas in both young and mature Rieslings are caused by the presence of a compound called 1,1,6-trimethyl-1,2-dihydronaphthalene (shortened, I can only assume for the sake of our sanity, to “TDN”). But recently three of France’s top producers have controversially suggested that the powerful petrol aromas found in younger Rieslings is a result of a fault in the winemaking process.
The first out the blocks was Michel Chapoutier. For those of you who are not familiar with Monsieur Chapoutier, he is one of the leading producers in the Rhône who has recently turned his attention to Alsace, launching his wines (which include a few Rieslings, as well as a Pinot Gris and a Sylvaner) under the name “Schieferkopf”. Chapoutier told Decanter magazine in May that “Riesling should never smell of petrol. That is a result of a mistake during winemaking.” Chapoutier has subsequently qualified his statement by saying that he is referring to the petrol aromas found in young Rieslings not those found in more mature Rieslings.
Hot on the heels of Chapoutier was Oliver Humbrecht, winemaker at leading Alsatian producer Zind-Humbrecht. Humbrecht was reported as saying in New York last month that the petroleum aromas found in young Rieslings are unattractive and caused predominantly by the decision to harvest under-ripe grapes and where the wine suffers from “reduction”. He suggests that reduction (the formation of hydrogen sulphide in the wine) can occur where the wine is made in airtight environments (such as stainless steel), through the poor use of sulphur or where the wine has been left on the lees (these are the dead yeast cells, pulp, skins, etc, that separate from the juice during fermentation).
What is interesting here is that Humbrecht, like Chapoutier, points the finger at the winemaker, suggesting that decisions made during the winemaking process directly affect whether or not the Riesling will develop a predominant petrol aroma in its early life – a characteristic which he views as a fault.
Then came the third in our trio – Pierre Trimbach of Domain Trimbach in Alsace. Agreeing with Humbrecht and Chapoutier, Trimbach suggests that petrol aromas in Rieslings which are less than five years old are a result of reductive imperfections. However, interestingly, he suggests that these imperfections are not in fact not caused by mistakes made by the winemaker but rather the direct result of how climatic and geological factors, such as water stress, soil types and exposure to UV rays, effect the vines and grapes.
Although these three high profile Frenchmen cannot reach agreement on the contributing factors for these petrol aromas, they appear to be of one mind when it comes to the view that this characteristic is undesirable in younger Rieslings.
But despite this view, it should be pointed out that this is by no means the opinion shared by everyone, as Chapoutier himself admits: “we are far from finding a consensus on this issue”.
At the end of the day we must not forget that drinking wine is meant to be a pleasurable experience and taste is subjective – some embrace the full-on forecourt-fuelled aromas that dominate some Rieslings, whilst others view these as overbearing and a sign of a fault in the winemaking process. Find what you like and sip away.