Sunday, August 18, 2019

Adding Oak Seasoning

The history of using wood for barrels and tanks is almost as old as wine itself. From about the 6th century to the 3rd century BCE, clay amphorae were used to store and transport various liquids such as oil and wine. But there was an inherent problem with amphorae: clay is porous and liquid leaks through it. So, the answer was to coat interior surfaces of the amphorae with pine resins.Today's Greek Retsina is the descendant of those early wines.

Yet, as important as wood is to winemaking, wine consumers hardly know of the presence of wood in the wine they are enjoying. 

Wine Cellars, Caves, Tunnel, Parabolic
Barrel Cave
Oaked Chardonnay is a case in point.  Beginning in the late 1970s, California Chardonnay, often with a heavy hit of new toasted French oak, became synonymous with white wine. An order in a fashionable city wine bar of the era for a glass of white wine, meant oaked Chardonnay.  

For hundreds of years, French oak has been the wood of choice for winemakers around the world. But shipping oak barrels from France to far-flung places like Australia, Chile and California was costly, so cost-cutting strategies were employed or locally grown woods were used.  Australian wineries opted to import American oak blanks, then fashion the barrels there. Chileans opted for an evergreen beech called rauli and California winemakers built large tanks from native redwood. For many years, chestnut was widely used in northern Italy.  Now wineries can choose from American, French, Russian and Eastern European oaks.

Winemakers, however, have settled mainly on either French oak or American oak. The planting, cultivating and harvesting of oak trees, mainly in northern France, is closely regulated by the French government. American white oak forests, mostly in the mid-west states of Missouri, Minnesota, Iowa, Ohio and Indiana, are privately owned. 

The use of wood as a seasoning for wine is an integral part of the wine's flavor and texture. Wood, more specifically oak, gives a wine texture, and more importantly, an added dimension of flavor. The trick is to select the type of oak that is most compatible with the wine and to gauge the right amount of time a wine is in contact with the wood.

The grain structure of American oak is tighter and less porous.  Thus, some winemakers   believe that American oak is too strong and sappy, especially for white wines. The feeling is that the more forceful American oak is better suited to big reds like Australian Shiraz (Syrah) and Cabernet Sauvignon grown in warmer climates. The flavor profile of American oak includes: vanillin (vanilla) higher in American oak than, coconut-like notes from lactones, cloves and firmer more assertive tannins 

French oak has an open grain and is more porous. There is a range of French oak types,  although a lot of the barrels are being sold as bois du centre, wood from the center of France. These are the most  common French oak types: Allier, a tight-grain oak from south of Sancere; Limousin, a wide-grain oak more often used for brandy aging than wine; Nevers, a tight-grain oak from forests near Allier; Troncais, a central France oak. Vosges, a tight-grained oak, similar to Allier and Never  French oak is noted for its softer tannins, sweet spices, sometimes with a hint of vanilla.

(How I Almost Raised a Barrel.  It's a snap, a piece of cake, I innocently thought as a burly man handed me a large metal hoop and pointed to an array of oak staves. 

The place was Napa, California and I was a "student" at the impressively named "College of the Oaks," administered by the French cooperage Seguin Moreau . During my years in college, I had struggled with many assignments, but building an oak barrel was a task I never expected to undertake. 

A cooperage is where barrels are made by a cooper. A cooper builds "raises" barrels forn the aging of wine and spirits, although there are other uses for wood barrels such as the maturing of balsamic vinegar. 

Image result for coopering tools
Cooper's tools
Traditionally, the coopers craft was a hands-on manual process that, until the last decade or so, had resisted mechanization. Oak staves were sawed, shaped and assembled, all by hand, to form a water-tight container. Today, machines do a lot of the hard tedious work, like shaping a stave and forcing the metal hoops in place to hold the barrel together.
Still, the inside of a cooperage is hot and loud. I was told by a director of one of the cooperages I visited in France that the coopers union is one of the best in France, assuring members work shorter hours, earn good salaries and retire earlier than members of many other unions in France. 

It was in this hot and noisy atmosphere where I faced my final test in the College of the Oaks.  Earlier, my fellow students and I had attended classes on the craft of coopering and the various types of oak trees and their characteristics that are used for wine barrels. Then, on the cooperage floor, we were asked to put our knowledge to the test. 

Basically, the process of raising a barrel by hand, involves selecting the required number of staves from a rack (including a strong and wide stave for the bung hole), resting one side of a "raising up" iron hoop on a stable surface, holding the other side of the hoop and then arranging the staves around the inside of the hoop.  

Sounds easy, right?  Well, you need a keen trained eye to select the staves that will fit exactly, one beside the other, so that the barrel will be tight and not leak.  All while keeping the other staves upright and holding the metal working hoop up, which is now getting heavier by the minute. 

Assuming you pass all of those steps successfully, with the hoop holding all of the staves upright (which is probably not gonna happen unless you're a nimble Dwayne Johnson), you then grab a wooden wedge and a hammer and work the hoop into its temporary position (?) by walking around the barrel while repeatedly striking the wedge driving the hoop down over the staves. The hammer doesn't feel that heavy when you pick it up, but think of bashing the wedge with the business end of a 12-pound sledge hammer, but with a short handle. 
Wine, Barrel, Wine Barrel, Barrels
Barrels waiting to be filled

Then, you tip the barrel and roll it over a fire fed by oak chips,to toast the interior and shape the barrel. Cables are wrapped around the base of the barrel and you turn a capstan bending the staves into shape. The two heads need to be inserted and the bung hole drilled, but by now, I've turned the barrel raising over to a cooper.

Full disclosure: I had more than a little help from a cooper raising my barrel.)

Toasting a wine barrel requires setting the open end of the barrel over a hot fire, for between five and 15 minutes, depending on the level of toasting: light, medium or heavy.. Toast levels vary by cooper, but in general the vanilla and coffee seasoning begin to show with a medium toasting, while a heavy toast is more roasted coffee, spices and even smoked meats.   

Finally, the heads are fitted into place and the new barrel is tested for leaks by injecting steam or hot water into a small hole drilled in the bung stave.  If the barrel is water-tight, the hole is drilled to bung size and the barrel is ready to be sold. 


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Next Blog: Is Riesling the World's Finest White Wine?

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