Ken Robertson

Better wine through chemistry

While leading a tour group through the Walla Walla area recently, I was asked a simple question: Do winemakers add some of those fruit flavors you’ve been talking about to their wines?

For this woman, who’s rather new to the idea of evaluating the aromas and flavors in wine, it was a perfectly logical question. And of course, it has a fairly simple answer: No, it’s not allowed, unless the wine is labeled accordingly. The amazing wine grape can produce all those aromas and flavors naturally.

But her question set me to thinking about the many things that commonly are used to help produce the white, rosé and red wines we all enjoy. The combination of perfectly ripened grapes and a skilled winemaker are requisites to make fine wine. But the end product, with all its flavors, aromas and gorgeously clear colors, is a testament to better living through chemistry.

So, what does happen in the winery that the average consumer might not know about? Let’s start with the chemical almost everyone has heard about — sulfur. Many associate it wrongly with “red wine headache,” even though white wines generally contain a bit more than reds. Sulfites and other sulfur compounds are used routinely in the winemaking process to stabilize and clarify wine, but very little ends up in it. In fact, there’s less sulfur in your wine than in dried fruit. Wine typically has about 150 parts per million (ppm) of sulfites, compared with 1,000 ppm for dried fruit.

Since 1987, U.S. winemakers have been required to label their wines if they contain more than 10 ppm of sulfites. Europe didn’t require similar labeling rules until 2005, leading to another common myth — that European wines are lower in sulfites. Sulfites are a concern, because about 1 percent of all people have sulfite allergies, which can be severe for some, and among asthma sufferers, the rate is perhaps 10 times that high.

Other chemicals also are used to stabilize wine, including dimethyl dicarbonate, which often is used in dealcoholized wine.

The wine headache issue leads to something else used in wine that can cause headaches for those who love sparkling wines — yeast. In sparkling wines, and in some white wines that are left on the lees to age for extended periods, the dead yeast can add autolytic compounds that give some people a “Champagne headache.”

Alas, without yeast to convert the sugar in grapes into alcohol, there would be no wine. In addition, yeast adds flavors and aromas and is carefully chosen for those abilities.

Tannin appears in wine both naturally and also is added by oak aging. Grape seeds, skin and stems contain it naturally. And these tannins especially stand out in red wine because reds are crushed more thoroughly to extract red color from the grapes, which also squeezes the grape seeds harder.

Fining and clarifying agents also affect a wine’s flavors and aromas, not by adding to the wine, but by subtracting from it. Egg whites, copper sulfate, isinglass, Bentonite, casein and gelatin are among agents commonly used to remove suspended solids that make wine cloudy. Too much clarifying, however, can leave a wine sparkling clear but with noticeably reduced aromatics and flavors.

It’s also common to add sugar to wine and often necessary when grapes don’t ripen to the point needed to provide the desired alcohol levels. The purpose is not to add sweetness. Chaptalization is controversial and banned in some areas, such as California, but allowed in others, including the Northwest. The philosophy of those who agree chaptalization makes sense (usually winemakers in cooler climates) is that sugar does not add aromatics or flavors, so what’s the harm?

Which leads us to adjusting acidity, or pH, in wine. Boosting acidity is frowned on by some, and done badly, it can produce a disjointed, out of balance wine. In the Northwest, wines seldom lack acidity, but at times winemakers will temper it, usually with calcium carbonate, alias chalk, especially in the coolest of growing areas.

Which leads to a closing thought about wine additives. Even water sometimes is added to the winemaker’s arsenal, usually when a too-hot harvest season results in high-alcohol wines that need a little toning down.

Wine words: Spritz

Spring and summer every year are the debut season for the previous fall’s crop of white wines. That means it’s time to dust off our wine word for this column, spritz. Anyone who’s been sipping wine and paying attention has likely encountered those little bubbles that form in a glass of wine as the wine comes into contact with the room-temperature glass and begins to warm up after spending several months in roughly 55-degree storage awaiting its release to the wine-buying public. In many cases, a tiny bit of fermentation continues once a wine is bottled and the bubbles are an indicator of that.

A little bit can enhance a wine, adding a zesty nip of acidity as the carbon dioxide bubbles emerge, which augments the wine’s complexity and helps its finish linger a bit longer. At a recent tasting with Wine Press Northwest’s judging panel, several members commented that a 2013 Pinot Gris being evaluated showed off the lovely aspects that a bit of spritz can add. But like many things in life and in wine, too much can be a problem. Continued fermentation can push the corks right back out of the bottles, creating a major mess and ruining the wine. In addition, the continuing fermentation can add undesirable odors and flavors, especially a burnt-match smell that indicates the presence of sulfur compounds.

-- Ken Robertson, the retired editor of the Tri-City Herald, has been sipping Northwest wines and writing about them since 1976.

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