Dan’s Cellar Notes for February 2006

By Dan Mouer

Oak and Wine, Part 2

Last month I described how oak and wine first came to be associated with other through the accidents of history. In response to the economic “globalization” of the 17^th and 18^th centuries, small cooperage became the standard for packaging and shipping large quantities of wine.

A 17^th-century seaport

Barrels in the wine port of Oporto

Not just any oak can be used to make a wine barrel. Two or three species of European oak, harvested primarily in France and the Baltic countries, as well as the wood of the American white oak are used worldwide. European oak tends to have a denser grain than does the American oak. American oak is usually sawn into staves—the long pieces of wood that are joined to make a barrel—while most European oak must be hand split—a more tedious, and more expensive, procedure. Among commercial winemakers, there are many different preferences for wood from specific regions of the various growing regions—some preferring only the wood from a specific forest! All coopers and winemakers seek oak from large, mature trees. We home winemakers generally only have a choice of buying our oak labeled simply “French,” “Hungarian,” or “American.”

Ideas seem to differ widely about the characteristics produced by oak from different regions. The Aussie winemakers have long preferred American oak—especially from Arkansas and Virginia. California wineries tend to use more French oak, or combinations of French and American barrels. The French have traditionally used both homegrown and Baltic oak.

The best oak meant for wine barrel construction is first “weathered” by allowing it to stand in the open air—sometimes even exposed to the elements—for at least one year, and more often for two or more years. This weathering may leach away some of the harsher tannins in the wood. It also shrinks the pores and makes a wood suitable for the needs of leak-proof storage.

Whether produced by splitting with froes and wedges, or by sawing, staves are the principal part of any wine barrel. They must be shaped using spoke shaves and scrapers of various sorts until they have the correct shape and curvature. Next, the staves are “pulled up;” that is, brought into the shape of a barrel with one or more steel hoops to hold them. The new barrel is placed over a fire to toast the inner surface. Toasting is done primarily to make a dense, leakproof seal inside the barrel. All winemakers and wine drinkers know, however, that the length of the toasting plays very important roles in determining the flavors that will be imparted to the wine.

Different coopers use different definitions for their toast levels, but, in general, you can find the following levels: light toast, medium toast, medium+ (also called “house”) toast, and dark (or “heavy”) toast. The heaviest toast levels never approach the charring found in whiskey barrels. I note this because it is a fairly common practice for traditional “country” home winemakers to use a charred whiskey barrel for fermenting and storing wines made from Concord and other native grapes. These barrels impart unique burnt-wood flavors—not to mention the very ample flavors and aromas of whiskey (!!!)—which are not typical of standard table wines.

Untoasted or very lightly toasted oak tends to impart flavors to the wine that are often described as “wood,” “oak,” “toast,” and “coconut.” With more toasting there is more caramelization of the wood’s own natural sugars. Typical flavors and aromas imparted by toasted oak include “butter” or “butterscotch,” “vanilla,” and “clove/cinnamon/allspice.” Heavier toasts also provide flavors described as “coffee,” “espresso,” “bitter chocolate,” and “burned toast.”

The advantages of barrel fermentation and barrel aging extend well beyond the simple chemical components of flavor and aroma imparted to wines. A barrel is a porous container. Very small amounts of air seep into the wine through the barrels wine-saturated walls, and both water and alcohol evaporate into the atmosphere. These two actions—micro-oxidation of the wine and evaporation of its liquid components—have profound impacts on the final product.

While oxygen is often wine’s greatest enemy, the slow process or micro-oxidation is thought to play a significant role in the maturing of a wine. It seems to help polymerize tannins, making the wine softer, rounder, smoother. It may help develop the complex “soup” of esters, aldehydes and other aromatic compounds that make wine…well…wine!

The evaporation of alcohol and water through the barrels pores cause the wine to become more concentrated. Throughout the period of storage, the barrel must be periodically topped up so that no airspace forms over the wine. In this way, more wine solids are being added, while liquid continually evaporates. In the end, the finished wine is denser, richer, more flavorful. While oaks flavors can be imparted with just a few months of aging in a new barrel, these other characteristics require many months or years of oak aging.

Oak barrels can perform magic when married with good wine. So everyone should use them, right? Well, in a word, “no!” More about that next month.

Know your grapes

Gattinara

Gattinara is a protected appellation of the wine produced in a small district in Italy’s Piedmont region. The wine, like its bigger brothers Barolo and Barbaresco, is made from at least 90% Nebbiola (also known as “Spanna”) grapes. If you should encounter a kit so named, expect a medium to full-bodied red wine with floral tones and the impact of spicy oak.

Grüner Veltliner

GV is a white grape that is widely grown in Austria, Hungary and the Czech Republic. I know of none being grown in Virginia, but at least one importer sells GV juice to home winemakers. GV makes a crisp, refreshing white wine with subtle flavors of lemon and peaches. It is usually finished with a touch of sweetness. It is one of my favorite summer wines.

Lambrusco

Lambrusco is a light-to-medium bodied bright red wine from Italy. It is almost always off-dry to semi-sweet—sometimes cloyingly sweet—and in its commercial guise it is usually packaged with a little fizz. Italians call lightly fizzy wines like this frizzante. Lambrusco soared to the top of the American pop-wine charts back in the 1970s, but it has fallen from favor more recently. It’s a great party or picnic wine. The perfect foil for the anti-wine-snob!

At least one kit manufacturer makes what they call a Lambrusco kit. I would not, however, recommend trying to make it “frizzante” unless you use champagne bottles and properly wired stoppers. Also, please become informed about how much added sugar causes how much extra fizz, or you might make Lambrusco grenades!!!. Of course, kits with residual sugar are normally stabilized with sorbate, and would not be likely to undergo any bottle fermentation. So, if you’re willing to forget the fizz…but then what’s the point??? :-}