The passing of oak barrel aging

March 13, 2008

From the time that wine came into being centuries ago, this important beverage has been stored in a variety of vessels. Wine must be stored in vessels to "age." Remember the old adage, "there will be no wine before it's time!" That was a true statement in ancient times and it is still a true statement today.

Now for a little history about the type and size of the vessels used to store and age wine. It was not until the Middle Ages that governments began to regulate the wine trade when some of the more common measurements were standardized. Even then the size and standards for wine vessels varied by country. A Medieval barrel held 10.01 gallons while the small 15th-century English barrel held 31.5 gallons.

Today, three types of small barrels are standard vessels world-wide for storing wine – the French oak Bordeaux barrel used for many types of wine holds 59.42 gallons (225 liters), the French oak Burgundy barrel, generally used for pinot noirs worldwide holds 62.2 gallons (228 liters), and the American oak barrel holds 55 gallons of wine.

Why oak barrels? Now for a little oak barrel information. Without oak, many wines as we know them today would not have existed. The wines would not have tasted the same – for there is NO substitute for the oak flavor. As any barrel manufacturer will tell you, wine barrels can be made from any wood, including pine, cherry, walnut or chestnut. When wine is stored in any of these barrels, their wood grain would not have enhanced the wine taste in the same way as the oak grain will! Therefore only the oak carrels were made to store and age wine.

From early on, vintners found that the flavor of oak has a desirable effect on wine by making the taste softer and tastier after aging in an oak barrel. Even today, they maintain that an oak barrel has the "ability to transform wine, to coax it out of the genre of simple fruit juice thus giving wine depth, length, complexity and intensity," according to Karen MacNeil, author of The Wine Bible.

Open wood buckets were used to hold and transport wine more than 2000 years before the birth of Christ. However, closed oak barrels only came into use during the Roman Empire. It was during this time that wine makers found that if they used oak for their wine vessels, it was strong enough to withstand "wear and tear," yet light enough to be easily rolled and moved in their wine cellars. But "best of all, the oak barrels were leak proof." So why not use them, because unlike today, oak trees were then plentiful in Europe.

Now, even though the vintners knew that the wine tasted better when aged in oak barrels, they were not sure why! It has only been within the past four decades that research has aided ecologists to unravel this "enigma." Researchers now speculate that there are possibly two processes that are responsible for this wine transformation.

The first is evaporation – both water and alcohol diffuse outward through the staves of a closed oak barrel – sometimes losing as much as 5 or 6 gallons a year. However, if the wine is aged in a sound barrel, the wine will age in a slow, reductive manner, thus eliminating the loss of wine. Process two also occurs at the same time as process one, with minute amounts of oxygen seeping in from the outside through the wood grain, which helps to "weave together the elements of the wine" giving it a softer dimension.

Now for a little information about steel barrels (tanks). It was not until 1912 that the giant German industrial conglomerate Krupp made the first steel tank. This stainless steel tank was not refrigerated, but it resisted corrosion from acids far better than the simple Chrome-steel tank it replaced. It was not until several decades later that technology developed a method for cooling huge tanks.

The first steel tanks used by wineries in the USA were probably those used by Gallo after World War II. Then finally in the 1950s, advanced rotary compressors capable of refrigerating 25,000-gallon tanks became available, and by the late 1960s, stainless steel tanks were a fixture in almost every American winery.

Needless to say, with oak barrels in short supply and costing at least $800 or more – steel barrels are more economical and easier to maintain. Now, what about oak flavor in a steel tank. You guessed it – just throw in some oak "chips" to get the flavor we wine lovers are accustomed to having in our favorite bottle of wine!

Buddy Harrell, Bennett Vineyards