Alcohol levels in Californian Cabernet
Despite talk of a move towards balance and restraint, Napa Valley Cabernet has never been riper or higher in alcohol. William Kelley follows the story through four decades of cyclical change, and asks whether it has to be this way
Too much of a good thing? William Kelley investigates the quandary of ripeness and alcohol in California
WhAT is RipENEss? it’s a complex question. As grapes mature on the vine, sugar accumulates and acidity levels drop, while tannins and pigments develop – and not necessarily in synchrony. so ripeness is not a moment, but a continuum (see graph, p41): herbaceous spiciness gives way to bright fruit, which in turn segues into compote, dried fruit, and finally roasted aromas of coffee and grilled meats; tart acids mellow; thin, green tannins gain in amplitude and grip before becoming lush and supple.
Deciding when to interrupt these processes determines a great deal about a wine’s style and character. in fact, it’s the most significant choice a winemaker makes each year.
Nowhere has the definition of ripeness been explored more thoroughly, or pushed to greater extremes, than in California’s Napa Valley; and Cabernet sauvignon, the region’s calling card, tells the story eloquently: the Us Department of Agriculture’s annual California grape crush reports (see table, p42) reveal that the average sugar content of Napa Cabernet has never fallen below 24 degrees Brix – a measure of sugar equivalent to 14.3% potential alcohol – since 1997. in 2013, the figure hit a record 26.3 Brix – that’s equivalent to 15.6% alcohol. And while data on individual wines is a closely guarded secret, anecdotal evidence suggests that many of Napa’s most expensive and sought-after wines may run considerably higher than those averages.
Whichever way you look at the numbers, they chart a dramatic evolution: contemporary Napa Cabernet sauvignon has never been so rich, ripe or high in alcohol. This is a style that succeeds and sells – the Napa wine trade contributed $50 billion to the Us economy in 2015 – but it also polarises opinion.
For some, the ease with which grapes ripen here makes imbalance in the resulting wines an ever-present danger. Dominus Estate’s Christian Moueix goes so far as to admit: ‘Excessive temperatures in Napa Valley make it a challenge for the wines to belong on a world-class level.’
On the other hand, veteran winemaker David Ramey, by no means one of Napa’s latest harvesters, speaks for many when he argues that Californians ‘should embrace the ripe fruit that is our birthright’.
Familiar question
For long-time observers of Napa Valley trends, the debates of the present day evoke a sense of déjà vu. in their day, after all, the powerful Cabernet sauvignons of the early 1970s drew similar criticism. Those ‘massive, often charmless wines’ appealed only to those who valued scale above ‘balance, subtlety, and just
‘Since humidity impedes photosynthesis, grapes in drier climates accumulate sugar faster’
plain drinkability’, complained wine writer Gerald Asher in 1984. ‘It was a time,’ agreed Warren Winiarski of Stag’s Leap Wine Cellars, ‘when California winemakers were asking what Cabernet Sauvignon grapes could give, as opposed to what they should give.’
The extremes of the present, however, bear only a superficial resemblance to the extremes of the past: Asher’s ‘massive, often charmless’ wines are mere striplings compared with the cult Cabernets of the new millennium.
The winemakers of today are prepared to accept unprecedented levels of sugar – and concomitant alcohol – in pursuit of fruitier flavours and riper tannins. So what were the forces that drove this radical transformation, accomplished in a mere three decades?
Inconvenient truth
It’s instructive to consider how Napa compares with Bordeaux, Cabernet Sauvignon’s home. Back in the 1960s, AJ Winkler’s
groundbreaking study, General Viticulture classified California’s grape-growing climates by counting the number of hours during which temperatures exceeded 10°C over the course of the growing season – a rudimentary but effective metric of a region’s capacity to ripen grapes. Winkler’s research indicated that the Napa Valley was comparable to Bordeaux, and thus ideally suited to plantings of Cabernet Sauvignon.
More recent research, however, reveals that the valley is actually considerably warmer than Winkler realised. General Viticulture, for example, stated that Oakville enjoys 2,300 hours above 10°C, a dead ringer for Pauillac; but the true figure is more than 3,200 hours. St Helena, assessed by Winkler at 2,900 hours, in fact racks up more than 3,700. These numbers have more in common with Provence than the Médoc: palm trees and aloes may not be indigenous to the Napa Valley, but it’s no wonder they thrive here.
The differences, moreover, run deeper than temperature alone. Oakville’s latitude, translated into European terms, places it somewhere to the south of Lisbon, so the sunlight that bathes Napa’s grapes is notably more intense than that which shines in Bordeaux. A similarly stark contrast can be drawn between Bordeaux’s humid maritime climate and the dry air of Napa afternoons: since humidity impedes photosynthesis, grapes in drier climates accumulate sugar faster, while the maturation of their tannins and flavours lags behind.
All this means that Napa Valley Cabernet Sauvignon is inevitably going to pack more of an alcoholic punch than classical claret. But it doesn’t explain why contemporary Napa Cabernet is picked at such dramatically higher sugars than it was in the 1960s and ’70s. Certainly, many of that era’s wines were tannic and herbaceous; but plenty of bottles from producers such as Heitz, Stag’s Leap, Chappellet and Joseph Phelps survive to prove that great Cabernet below 13.5% alcohol was a real possibility not so long ago. What changed?
Viticultural revolution
One answer lies in the vineyards – complex holistic systems, where changing any variable has manifold consequences, some intended, others not. A landscape littered with different vine pruning systems reflects decades of experimentation. Gnarled head-trained vines, planted only six feet apart, are relics of the 19th century. Then Prohibition wiped California’s viticultural slate clean, and in its aftermath new vineyards were planted with wider spacing, designed to accommodate cumbersome tractors and pick-up trucks.
By the 1970s, a rudimentary ‘T-trellis’ had been introduced, with wires to lift the vine’s canopy above the fruiting zone, the shoots
flopping down between the rows in what became known as California sprawl.
There were problems with California sprawl, especially in fertile sites on Napa’s valley floor. Planted at low density and often generously irrigated, vines grew extravagantly: ‘It rapidly became a jungle, with more leaves than anything else,’ says Chris Howell of Cain Vineyards. ‘Yields were bigger and green flavours lingered longer,’ recalls Cathy Corison.
By the 1980s, winemakers were exploring alternatives, and many looked to Bordeaux for inspiration. A decade earlier, a young Ric Forman had already travelled to the Médoc and returned to plant experimental vineyards at Sterling, emulating the careful trellising and close spacing he observed there. On a later visit, in 1980, Forman was joined by David Abreu, an up-and-coming vineyard manager, whom he inducted into the mysteries of French viticulture. ‘David was just enthralled by the whole thing,’ Forman recalls, and Abreu returned to Napa eager to implement the best of French practice, soon emerging as the valley’s premier viticulturist.
Around the same time, Tim Mondavi also began experimenting with closely spaced, trellised vines – imitating the techniques he had observed at Château Mouton Rothschild, the Mondavi family’s partner in their then new joint-enterprise, Opus One. Pruned close to the ground and spaced four feet apart, Mondavi’s vineyards could have been transplanted directly from the Médoc.
Others followed suit, or pursued similar experiments independently. And their intuitions were compounded by advice from viticultural scientists, led by the Australian consultant Dr Richard Smart, who conducted workshops and advised wineries, including Mondavi. Smart preached opening up canopies to light and air; and for winemakers wrestling with unruly California sprawl, the message seemed timely.
Change, in short, was in the air; and it was dramatically accelerated by the second coming of phylloxera at the end of the 1980s. Vast swathes of Napa’s vineyard acreage were ripped out and replanted; and many growers took the opportunity to put new viticultural theories into practice on a grand scale.
Closer spacing and more sophisticated trellising were paired with new rootstocks and virus-free Cabernet Sauvignon clones, which favoured earlier ripening. The higher vine densities meant that drip irrigation, already commonplace, became the norm – and conveniently, fertilisers and treatments could be applied through the water supply simultaneously. ‘It’s a growing system not dissimilar to hydroponics,’ says John Williams of Frog’s Leap, one of the valley’s most ardent advocates of farming without irrigation, ‘and it created all sorts of problems.’
‘Head-training is better adapted to our climate and helps the vine self-regulate’ Graeme MacDonald
Clearer picture
The new vineyards were beautiful. But there were unintended consequences: the wines didn’t taste the same. ‘It took me 10 years to figure out I was wrong,’ says Howell, who had studied in France and began experimenting with Bordelais pruning systems shortly after he arrived in Napa in 1984. ‘I began to notice that the tannins were different,’ he recalls, ‘but I was such a committed Francophile that, for a while, I questioned my own perceptions.’
In retrospect, it’s hardly surprising that viticultural practices designed to maximise ripeness in Bordeaux’s marginal climate should prove poorly adapted to the Napa Valley’s considerably warmer conditions. Not only were the wines’ tannins more aggressive, but they were also intensely green and herbaceous. New techniques in the cellar couldn’t solve the problem, and gradually it became clear that the only solution was to pick later, harvesting riper fruit with higher sugars. ‘To make the wines softer, we had to make them bigger,’ explains Chappellet winemaker Phillip Corallo-Titus, who typically picks at around 28 Brix today.
Since the early 1990s, of course, viticulture has progressed considerably: Napa grape growers are more careful to avoid excessive sun exposure; a small but growing number are pursuing dry farming, too. Trellising has evolved, and several growers are rejecting it altogether, reverting to the head-trained pruning of the 19th century. ‘It’s better adapted to our climate and helps the vine self-regulate,’ argues Graeme MacDonald, who stewards some of the oldest head-trained Cabernet vines in the valley and has first-hand experience of the system’s advantages.
So, while the legacy of vineyards that only ripen grapes at high sugar levels is very much with us, it’s increasingly the subject of critical thinking. ‘We’re still learning,’ concludes Chris Howell, ‘and that’s good.’
A matter of taste
If Napa Valley viticulture has changed radically since the 1970s, so too has the
‘It took me 10 years to figure out I was wrong,’ Chris Howell, Cain Vineyard & Winery, above