“Consumers have done an 180 degree turn from green styles of Sauvignon Blanc over the last decade. They are looking for a balance of tropical fruit aromas (thiols) and green pyrazine flavours” announces Martin Moore, the burly cellar master at Durbanville Hills. The big shift in Savvy thinking began in the vineyard after buyers and consumers on shows abroad asked him for more tropical fruit in the wine. “Instead of protecting the pyrazines, we now strip the vine canopy to expose grapes to sunlight and encourage the growth of thiols” (tropical aroma compounds/precursors).
Winemakers showcased the signature white grape of the Durbanville Wine Valley at a recent harvest media day at Diemersdal where family winemaker Thys Louw makes some 900 000 litres of Sauvignon Blanc under seven labels - including the biggest-selling Sauvignon Blanc at Woolworths. The Durbanville Twelve - the dirty dozen who all contribute grapes to make a Sauvignon Blanc representative of the whole valley - came out with wines blazing on the subject of green (capsicum, asparagus and tomato leaf/khaki bos) aromas and flavours typical of pyrazine wines - versus tropical (grapefruit, gooseberry, guava, passion fruit and cat’s pee) thiol character.
Celebrating a decade at Altydgedacht, winemaker Etienne Louw adds, “If you want to make wines that people want to drink, focus on the fruit. When I first arrived, I made an expressive green pyrazine Sauvignon Blanc. On shows in Europe, our agents asked, ‘But where are the tropical fruit flavours consumers like in South African wine?’ Since then we’ve made strongly thiol-driven Sauvignon with a guava, fruit salad signature. We pick later for thiols as precursors to aroma and tropical fruit.”
Altydegedacht is a winery to watch when it comes to spotting consumer trends. As a flag-bearer for alternate varieties with signature bottlings of Barbera, Gewurztraminer and Weisser Riesling, Etienne emphasises that, “If you make unusual varieties, you really have to stand behind them. Alternative varieties are very much for on-trade consumption we export to Europe. The wine consumer is still a very conservative market. If you put an unpronounceable variety on the label, it might not sell”. Diemersdal is a case in point - it exports much of its new Gruner Veltliner to Austria.
“A wine that is complex really stands out in a Sauvignon Blanc tasting” agrees Charles Hopkins, cellar master at De Grendel and convenor of the annual FNB Top 10 Sauvignon Blanc panel. He calls the right blend of thiols and pyrazine “the golden seam” of Sauvignon Blanc. In pursuit of the ideal analytical framework for Sauvignon Blanc, the Sauvignon Blanc Interest Group conducted a study of fifteen variables in forty Sauvignon Blancs sourced from every region in South Africa. He highlights the influence of thiols, pyrazines, dissolved oxygen and the low levels of residual sugar (under three grams) in winning wines in the top ten Sauvignon Blanc competition.
Looking back on thirty years of making wine in South Africa, Hopkins says, “It’s not the easiest variety to make - and so much evolution is taking place in Sauvignon Blanc. What is the sought-after flavour - tropical thiols, green methoxy-pyrazines or a combination?” A teaspoon of either goes a long way in the tank - infusing those signature cat’s pee, gooseberry and passion-fruit flavours. He says Sauvignon Blanc is the fastest growing variety in South Africa - where it makes up 9% of plantings and consumption - and notes the growth in the wooded Sauvignon Blanc category.
A lesson in the comparative merits of thiols and pyrazines continued at a tasting of Sauvignon Blanc led by Johann Fourie, chief winemaker at KWV and Diner’s Club Winemaker of the Year in 2015. Over a recent tasting at the manor house at Laborie (1691), he contrasted three styles of Sauvignon in KWV’s award-winning Mentors range sourced from Stellenbosch, Elim and Darling. While the Mentors Sauvignon Blanc 2012 (Bottelary Hills) demonstrated the longevity of wine with a marked pyrazine character (all canned pea, cut grass and capsicum flavours); the Mentors Sauvignon 2014 (Elim) expressed its complex cool-climate origins (with gooseberry, asparagus and oyster-shell flavours); whereas the Mentors Sauvignon 2014 (Darling) combined both dimensions in a wine with lime, gooseberry and sweet melon flavours.
Fourie comments, “The real strength for me is the flinty, steely and mineral style of the Elim Sauvignon with its austere structure which lends itself to great aging ability and will benefit from secondary flavours developing with bottle maturation.”
“Together with canopy management and yeast selection, another important technique is the use of skin contact on Sauvignon Blanc or not. Many winemakers have different opinions. I'm of the opinion that it improves both levels of thiol precursors and pyrazines (which is both as you can see from the attached grape skin derived). The flip side is the high levels of K+ in the grape skin which neutralises your natural acidity and makes your pH go up (not what you want!) so it's a bit of a balancing act. More regions like Darling and Durbanville have higher levels of potassium so one has to be even more cautious with extended skin contact on grapes from there.”
“We love methoxy-pyrazine on Sauvignon Blanc but don’t want any green flavours in its love-child Cabernet Sauvignon” says KWV head viticulturist Marco Ventrella on a walkabout at Grondves (Foundation) vineyard in the Helderberg. He pointed out some of the sixty new clones and varieties which may well signpost the future for South African wine in the search fro drought-resistant varieties in the global warming era.
On a tour of a global nursery newly planted to rare varieties inter alia such as Assyrtiko, Carmenere, Primitivo (Zinfandel), Sangiovese, Terret Noir and Vermentino, he comments, “We love planting new varieties, pushing out the envelope. Mentors is all about experimentation. A tasting of alternate varieties in the Mentors micro-cellar at KWV in Paarl also highlighted the amazing longevity of bottle-aged Grenache Blanc, Semillon and Verdelho - as well as the potential of 2016 tank samples of Grenache Noir, Petite Sirah (Durif), Malbec and Tempranillo.
The diversity of terroir in the Cape seems to lend itself to a versatility of Sauvignon Blanc styles. Thirteen different regions were short-listed among the top twenty wines competing for a place in the FNB Sauvignon Blanc Top 10 in 2015. The cooler climate areas of the Overberg - Cape Agulhas (bottle-aged Lomond Sauvignon perfectly expresses the winning thiol/pyrazine combination sought by consumers), Bot River, and Elgin - have come to the fore in recent years. But Cederberg, Groenekloof/Darling, Durbanville and Stellenbosch also show well on the competition - as do multi-regional blends of Sauvignon which combine thiols and pyrazines in winning wines like Mulderbosch 1000 Miles and Nederburg II Centuries.
If you think thiols and pyrazines are the stuff of wine geeks, consider how a savoury flavour compound like umami is commonly bandied around in food and wine circles these days. A good place to start to understand how thiols and pyrazines determine varietal character and wine styles in Sauvignon Blanc is the overview of a pioneering study by JH Swiegers et al called ”Meeting consumer expectations through management in vineyard and winery” by the Australian Wine Research Institute published in the Wine Industry Journal (Vol 21/No1, Jan/Feb 2006).
The study emphasises that, “The tropical characters in Sauvignon Blanc wines come primarily from volatile thiols in the wine with contributions from fermentation-derived esters.” If you’re with me so far, it discusses three primary types of thiols: 3MHA and 3MH which impart passion fruit, grapefruit, gooseberry and guava type aromas - and 4MMP which imparts passion fruit and box hedge aromas, which, when very concentrated, can impart sweaty aromas reminiscent of cat’s pee. It also notes grapes grow in cooler climates (New Zealand) typically have more concentrated methoxy-pyrazines than those from warmer climes. The most common MPs are IBMP (capsicum and asparagus aromas) and IPMP (earthier aromas).
The authors conclude, “A particular and lucrative market segment is increasingly interested in Sauvignon Blanc wines that display both green and tropical characters … While the green characters in Sauvignon Blanc can be manipulated through vineyard management, the tropical characters appear to be largely dependent on the wine yeast strains used during fermentation (particularly Vin7 and Vin13) …
"Yeast selection appears to be one of the most promising tools in manipulating the passion fruit, grapefruit and gooseberry aromas. A combination of environmental and viticultural influences and winemaking practices will determine the delicate balance of fruity, tropical aromas and the herbaceous, green flavours that define quality, new-world Sauvignon Blanc styles which consumers would prize highly”.