Bad Riesling and unleaded petrol
11 Jan 2017
Aged Riesling has long been associated with the smell of petrol. Some might call it kerosene or diesel, whatever, it sounds scary to new wine drinkers and heaven to many devotees.
For decades this has been explained as a natural occurrence during the aging process, and for many a desirable sign that the wine is mature and nicely displaying varietal characteristics. Suggestions are that it is a breaking down of certain molecules over time or that it is molecules which were masked during a wines youth by stronger molecules which have diminished. Or not….
Science has revealed it to be caused by TDN, a compound consisting of some 27 letters and many numbers i.e. not to be troubled with here, but there is no doubt it gives Riesling its 95 octane aromas. Exposed fruit develops more TDN.
What is debated, quite strenuously, is whether TDN is desirable or, in fact, a fault.
“It’s a fault, of course it’s a fault”, says Peter Barry, owner, proprietor and winemaker at Jim Barry in the Clare Valley, South Australia.
Peter is in no doubt that it is caused by sunburnt grapes.Peter is not one to argue with, when he says something, you listen and like his “best mate” Ken (Forrester) he has more wine knowledge than you can shake a stick at. Peter muttered that Ken’s ‘FMC’ is “a ******* good wine”. Peter’s language is as uncompromising as he is.
He doesn’t support the theory proposed five years ago by Michel Chapoutier that the petrol note was due to poor winemaking, Peter says it occurs in the vineyard.
“Riesling is ten times more susceptible to sunburn than other varieties”, so that is why we pick it up mostly in that variety. “We can detect it around 600ppm”, says Peter, “but even if it is around 200ppm people believe they can detect it, they are looking for it”. Good aged Riesling should offer honey, musk, burnt marmalade. Mitchell Wines in Clare agree, good old Riesling should be “toast and bitumen”, they say. No petrol.
A similar story in the Eden Valley, where iconic label Henschke’s owners Pru and Stephen have banned their staff from using the ‘d’, ‘k’ or ‘p’ words. “We look for buttered toast in older Riesling”, says brand ambassador
Barossa winemaker, ex-Cape winemaker, half of the Radford-Dale South African wine brand, and surfing buddy to many current SA winemakers, Ben Radford, at Rockford, agrees that petrol notes are a fault.
But why, I ask Peter, if it is caused by sunburn, does German Riesling often smell so, when summers may not be that hot?
“Because in order to expose the bunches to maximize the sun, leaves are stripped back, developing berries are exposed and the fruit has no time to develop any resistance – its own sunblock – so even in cool climates they are vulnerable”.
“I hate it, absolutely hate it”, (with some generous Aussie language), says Peter, “and us Clare winemakers have agreed to have none of it”. His 2008 Florita Riesling displays layered sherbet, burnt quince, orange peel, the classic smack of lime; again, no petrol.
“I take the tip off of canes, forcing the vines to produce lateral shoots to shade bunches”, this gives them double protection, a chance to develop their own sunblock and extra shade. There is still plenty of ripening, “we know the balance”. Fruit is only exposed if it needs to be and when it is able to cope with the stress.
Peter is a winemaking enigma, he believes “we’ve got nothing broke, so nothing to fix, but we chase progress and technology”. He has a winery section just for experimentation and has top staff; even his cellar door manager is a qualified winemaker. “They are free to make any suggestions to improve my methods, but it must improve, this is not a school debating society, don’t just disagree with my thirty years of experience, add something or **** off”.
Riesling has a three day window of ripeness, says Peter, outside of those three days you lose any chance of optimum fruit. Picking at the right hour, not just the right day, is vital. “That’s why I machine pick and have three harvesters of my own, I can say ‘go’ when I know the moment is right, hand picking, or worse, sharing a harvester, doesn’t allow you that precision”. He still selects rows and parcels and vineyards in their picking order and calls their very moment.
Ben Radford believes in harvesting by hand, but agrees with the small window of opportunity with Riesling and says that the modern machine harvesters are so much kinder to the berries and vines, and have effective sorters on board too.
It is official then, petrol notes are a fault on Riesling, unless you want to argue with Peter.