A Chilling Effect on Quality

As if wine makers didn’t have enough headaches, add a new one to the list: a cold spell that could lead to what I call the Fargo Syndrome.

A few days of rare freezing temperatures hit Napa and Sonoma in December. Vines were unaffected because they are dormant at this time of year. But the freeze posed a threat to bottled wine in warehouses that are not temperature-controlled.

As a result, in a few months wineries may start getting letters from irate consumers complaining about “the ground-up glass” in bottles of Chardonnay. It’s enough to make a wine maker turn to drink. What the customers will be complaining about is probably not glass at all.

All grape wine contains tartaric acid, a natural acid in the grape. If a wine is chilled too much, the tartaric acid crystallizes and falls to the bottom of the bottle--harmless and relatively tasteless. The only drawback is that the crystals look funny floating around when you shake the bottle.

To keep this from happening in a cold snap or in the back of a refrigerator, wine makers routinely cold-stabilize their white wines, chilling them before bottling to remove the crystals before they can form in the bottle.

But this isn’t necessarily good for the wine. Those wines that “throw a deposit,” as it is phrased, are usually better if they haven’t been cold-stabilized. Unless it is done very carefully, cold-stabilization robs the wine of some of its flavor and aroma.

The other day I was going through a wine rack stored in a garage in Sonoma County. I saw that the 1989 St. Clement Abbott’s Vineyard Chardonnay ($18) had a layer of crystals at the bottom.

I tasted the wine. It was marvelous. The citrusy elements of lime and grapefruit were combined with a delicate floral note and very complex finish that was tart but inviting. I likened it to a fine Chablis, and I found it wonderful. Virtually unchilled, it was sensational with baked trout.

I called Dennis Johns, St. Clement’s talented wine maker, and asked him how he treated the wine.

“Sure, we cold-stabilize,” he said, “but you almost have to freeze the wine to get all the tartrates out, and I just don’t believe in chilling it so low that the wine suffers.”

He acknowledged that if his Chardonnay is held in cold temperatures for a long time--such as the sub-40 degrees of a restaurant cold box--it will throw some tartrate crystals.

“We chill (the wine) enough to get rid of the threshold level of tartrates, down as low as 40 to 42 degrees, generally what refrigeration temperatures might be.”

Johns said he wasn’t certain that chilling colder than 40 would hurt the wine appreciably, “but we do know that the wine isn’t made better by it.”

One wine maker once told me he chilled his white wines below 24 degrees to guarantee no tartrates will form in the bottle. “It’s commercial suicide if you don’t freeze it,” he said. “I don’t want to get sued by someone who thinks the wine has glass.”

Yet chilling a wine near freezing must hurt the wine. Basic chemistry tells you that when wine is held very cold, the solubility of gasses is greater, so it’s more likely to oxidize.

Most red wines will throw a tartrate deposit over time, but most wine makers believe that consumers are a little more forgiving with red wines. Consumers assume that some sludge in the bottle is the price you pay for fine wine. But they are not as understanding with crystals in white wine.

The best way to remove tartrates from wine is to “seed” the wine with finely ground potassium bitartrate powder--the same stuff the wine makers want to remove. It acts as a site on which more tartaric acid can collect. Gravity pulls the stuff to the bottom.

When this is done in a tank at the winery, the sludge in the tank is recovered and sold to spice companies, who convert it to cream of tartar.

Johns said he wished he didn’t have to cold-stabilize any of his wines. They’d be better, he said. “Our decision to do it,” he said, “was based solely on consumer acceptance.”

Wine maker Clark Smith, a consultant for Glen Ellen Winery, has extensive experience with cold-stabilization, and he noted that when it’s done right, it doesn’t hurt a wine. But, he admits, it’s hard to do right.

“Chardonnay is one wine where I have seen very gross bottle shock occur,” he says. “The wine tastes strange for months after bottling. I feel this adolescence is brought on by oxygenation . . . (which) can occur during cold-stabilization if the wine isn’t carefully protected.”

So if you see a wine with crystals at the bottom of the bottle, or on the cork, don’t automatically accuse the wine maker of sloppiness. It may be a sign that the wine maker was concerned about robbing a delicate wine of its nuances. It’s often a mark of quality.

Wine of the Week

1988 Robert Sinskey Pinot Noir, Estate Bottled ($18)-- The Carneros region, just off San Pablo Bay at the southern tip of Napa and Sonoma counties, has gained wide acceptance as a great area for the Burgundian varieties (Pinot Noir and Chardonnay) and sparkling wine made from them. Dr. Robert Sinskey, a Los Angeles eye surgeon and one of the original founders of Acacia, bought vineyards in Carneros in 1982. Four years later, with veteran Joe Cafaro handling the wine making, Sinskey began producing wine under his own label.

This wine is a spectacular example of the fruit of the region, with cherries and wild strawberries in the aroma; deep, rich fruit in the mouth and a long finish. There’s also a hint of clove and cinnamon. I think Sinskey Pinot Noirs will soon be recognized as some of the best in this country. This is just a glimpse of things to come.