Clonal Variations: Taking Chardonnay to the Next Level

Wine lovers have long been fascinated by the role clonal variations play in wine character. It’s not enough just to know the grape variety, the vintage, vineyard and winemaker; the specific genetic strain counts too. Recent vintages have yielded an increasing number of clone-designated Cabernet Sauvignon bottlings. Now, it’s Chardonnay’s turn.

For the last five vintages, Chalk Hill Estate (in Sonoma County’s Chalk Hill area) has made wines from 17 Chardonnay clones. It recently released six of the most consistently outstanding for tasting.

Chardonnays made from the same clones have been around for a while, but it has been hard to get at their essential flavors and compare them because they’ve been made by different producers. To my knowledge, this is the first time a winery has presented a set of polished, commercial-quality Chardonnays in which the only significant variation is clonal.

It is astonishing--the voices of the six wines are as distinct as those of, say, six different piano virtuosos playing the same piece on the same instrument. In theory, each clone has its own character, which is asserted to some degree in the character of the wine made from its fruit. Their delicate voices may not stand out in the final blend--indeed, they shouldn’t--yet each makes a decisive contribution, as if each musician in an orchestra were a first-rate virtuoso.

Given that site remains the most important determinant of wine character, regardless of clone, Chalk Hill Estate is a pretty good testing ground. The estate has 13 soil types in a wide variety of exposures, providing a wide range of vineyard situations.

“You can’t just look at the data,” winemaker Bill Knuttel says. “You have to grow the vines, harvest the fruit, make the best wine you can, and then taste the wine over time. And you have to repeat that vintage after vintage. It’s expensive and time-consuming, but it’s the only way to properly assess the clones.”

Therefore, the winemaking for these clonal selections was identical. Essentially, it followed the basic Chalk Hill Estate regime: whole-cluster pressing, barrel fermentation, aging on the lees with monthly stirring. All the wines were aged for the same length of time, fined to the same degree and bottled with the same level of sulfur. They were not filtered.

The only significant departure from Knuttel’s normal protocol was that the primary and malolactic fermentations were standardized by using commercial strains of yeast, rather than naturally occurring ones that can vary. That eliminated the possibility of curveballs that might blur the picture by affecting wine character.

Like Cabernet Sauvignon, Chardonnay has won wide popularity that has taken it to every notable wine region in the world. Chalk Hill Estate’s plantings are a veritable United Nations of Chardonnay.

Of the Chalk Hill wines, I particularly like the one made from the venerable Martini Selection, a.k.a. Clone 4, which was selected in Chardonnay’s homeland, Burgundy, and propagated in Livermore Valley by the Wente family in the 19th century. From there it went to Stony Hill in Napa Valley, and therefore to the Louis Martini family vineyards.

Clone 4’s ability to yield a large crop of reasonable-quality fruit has earned it the nickname Super Clone. That might imply that it yields mediocre wines, but the opposite is true: When grown on the right soil and balanced for low yield, it gives concentrated, complex wines.

“It’s unfortunate that nobody looks at the old clones,” notes Knuttel. “It’s a mistake, because they have their places in the right vineyards.”

Chalk Hill’s 1999 Clone 4 bottling is a good example. It combines power and finesse, luxuriant fruit and crisp definition, with tropical fruit and peach inflections--classic California Chardonnay.

Clone 16 was selected in Rutherglen, a warm area in the state of South Australia, and subsequently certified by UC Davis. The key to its distinctive personality is the acid balance of its fruit: relatively high in malic acid and low in tartaric. Malic acid is less stable than tartaric acid. It decreases during ripening, and the loss accelerates as the mercury rises. So, especially in a warm climate, the finished wine is already low in acidity, even before being further reduced by malolactic fermentation.

But Chalk Hill’s bottling is a lovely wine, rich and balanced with a creamy texture and bright citrus notes. It definitely has its place in a blend, contributing a rich perfume and luscious fruit to without throwing the total acidity out of balance.

Clone 17 was originally selected from the famed Robert Young Vineyard in Alexander Valley, just a few miles from Chalk Hill Estate. It is more subdued and less perfumed than either Clone 4 or Clone 16, yet it has a higher-toned nose and brighter palate, with a mineral undertone that tends to focus and define the lusher tropical fruit elements around it.

In contrast to the previous four, Clone 22 was selected from a cool climate. It comes from Conegliano in the Friuli region of northern Italy. Not surprisingly, its wine is on the lean, herbaceous end of the Chardonnay spectrum. Clone 22’s virtues in a blend are brightness and a firm, even weight on the palate. It draws a defining line through all of the complexity.

I thought Clone 76 was the outstanding wine of the set. I wasn’t alone, Knuttel tells me. It’s consistently the most preferred wine in blind tastings. That’s not surprising--it comes from Dijon and shows the classic Burgundian Chardonnay values. The heady Chardonnay perfume has tropical notes and an underlying stoniness that expands through the palate as the lush first impression tapers into firm, tight-grained minerality and a long, radiant finish.

Clone 352, also from France, shows a fine, high-toned creaminess with a delicate white-blossom perfume that evokes the still wines--fully ripe and oak-aged--from vineyards in Champagne’s Cote des Blancs. At the same time, it has what Knuttel calls “a woody apple character” that’s very Russian River Valley.

Chalk Hill Estate’s Chardonnay clone trials are the most comprehensive ever undertaken in California. Still, they’re just a beginning. There is so much more to be learned about how to produce the clearest possible expression of a varietal wine from a unique planting. Luckily, the finest Chardonnays from this or any other wine estate still shine in the future.