How blending makes our wines better

There’s a renewed enthusiasm among winemakers for blending. Is it the challenge of weaving together the flavours of different grape varieties? Is it the search for something new out of the old? Or could it be because at least two of the wine world’s most prized regions, Champagne and Bordeaux, rely predominantly on blends?

We are seeing increasingly daring feats of blending, such as the five grape wines from South America that feature Malbec, Syrah, Merlot, Cabernet Sauvignon and Franc. Even French winemakers are experimenting, with combinations like Grenache Blanc, Marsanne and Vermentino.  And just as Australian winemakers like Peter Barry of Jim Barry wines, are grappling with Santorini’s famous grape, Assyrtiko, Greek wine makers, who have built a reputation on this grape variety, have started blending it with overseas varieties like Sauvignon Blanc and Semillon.

Blending is an art as well as a science and it takes considerable skill. Critics will tell you that they know what each grape variety provides to the blend—except, perhaps, in the case of Châteauneuf Du Pape, where Château Beaucastel blends at least 13 different grape varieties—but they are over-claiming. The proportions of each type of grape are determined by trial and error. Like perfumers who mix molecules until the separate aromas are no longer distinguishable and a new scent, known as an “accord,” emerges, winemakers search for a unique and unified whole.

So, while critics will tell you that Chardonnay adds finesse and elegance to a Champagne, while Pinot Noir provides it with structure and red fruit character, few, if any can tell by blind tasting how much of each the blend actually contains, as my colleagues and I showed in a published study.

As we argued, we shouldn’t expect tasters to discern the parts that contribute to the whole; that would be a failure of blending. In fact, chefs de caves in Champagne are aiming for a cuvée whose fully integrated aromas and flavours no longer betray their origins in the base wine. It would be a broken-backed wine in which we could taste just which grapes were responsible for which characteristics.

Surprisingly, as little as 5 per cent of the wine from a given grape variety can make all the difference to a successfully blended wine. Winemakers will tell you that adding more than 5 per cent often results in less successful blends. But can 5 per cent really make a difference—and how does it do it if so?

Perhaps it is because a small departure from an otherwise uniform flavour profile piques our interest. However, we mustn’t get carried away by the rule of working in the 5 per cent. Oenologist Tony Milanowski, from Plumpton College, told me about one Australian winemaker who had tried blending Cabernet Sauvignon with Petit Verdot. He found better results when he reduced the Petit Verdot from 30 to 20 per cent. After that he tried reducing the percentage from 20 to 10 and things got even better. Eventually he added no Petit Verdot at all and the wine was just marvellous.

Even when relying on just one grape variety, winemakers like blending—it’s part of their training. They often blend from different barrels because they vinify different parcels of  grapes separately, before deciding how much of each barrel goes into the final wine. When deciding this, it is seldom that just the best barrels go into the finished wine. Again, departures from uniformity are better at grabbing our attention.

So whether it be tea, perfume or paint, blending remains a distinctively human achievement by which we reach something even more pleasing from samples we already know. It is widely practiced in the wine world, and we are immeasurably better for it.