March 01, 2012
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Roll Out the Barrels

By Jason Lett

Racking is the process of moving wine off of the solids that have settled to the bottom since harvest. After racking, the barrels are washed and stacked for reuse. All this cleaning means we’ve been rolling a lot of barrels lately, and, once again, I am struck by the absolute marriage of form and function the barrel represents.

The shape of the barrel and the process of making one have been basically unchanged since the Iron Age in northern Europe. The Roman Army adopted the barrel for the transportation of goods from their Celtic enemies 2000 years ago, and by the third century it completely replaced the clay amphora as the container of choice for transporting wine. 

Even though it’s an ancient technology, the barrel is still an essential element in creating the world’s wines. As we roll barrels, we are engaging in one of the only activities in winemaking unaltered since the Roman era. Grapes are no longer pressed by foot in stone troughs cut into the floor. We fill and empty barrels at the flick of a switch or a nitrogen valve, not with a clay pot. But the act of moving a barrel around the winery, and, once filled, the dynamics experienced by the wine aging inside, have not changed in thousands of years.

One indication of the sheer functionality of each part of the barrel is that the form and parts of a barrel do not vary much among manufacturers. 

Every barrel is made of planks, called staves, shaped and chamfered to create the shape of the barrel when bent together. One of the wider staves will have a hole drilled into the middle called a bunghole, which allows the barrel to be filled later. Each stave also has a bevel, called the “chine” cut on the outside ends and a groove, the “croze,” just inside that. When the staves are bent together over heat (traditionally over a fire,) the two circular ends of the barrel, called the heads, are slipped past the chine and set into the groove of the croze. The staves are further tightened with a winch.

Hoops — metal now, strips of green chestnut in the past — are pounded down around the outside of the barrel, holding the staves in position around the heads. Once filled, the wine inside the barrel swells the grain of the wood, forcing the joints between the staves together so tightly that no wine leaks out. Just as the wine needs the barrel, to protect it from air and nurture its aging, so does the barrel need the wine, to prevent its staves from drying, shrinking and collapsing on themselves.

One of the most miraculous aspects of the barrel is that, with the exception of the hoops, it is still made without metal fasteners. True, many manufacturers now use tiny metal pins to hold the boards of the barrelhead together during assembly, but some still use wooden pegs.

The form of a barrel, a cylinder tapered on both ends, is what allows it to function so beautifully. Its shape gives it structural integrity, makes it easy to move, protects the wine from oxygen, and facilitates clean racking. (See side bar for more details.)

The beauty of the barrel lies in its functionality on many levels. But shape is only one of the barrel’s attributes. It is, in itself, a great expression of wood and of the woodworkers art. Once filled, the barrel becomes an important contributor to the aging of the final wine — and working with them is a ritual that makes us part of a very long history.

Jason Lett grew up working in the vineyards and winery of his family’s Eyrie Vineyards in the Willamette Valley. In 2005, he returned to make the wines at Eyrie as well as BlackCap.

AN IDEAL DESIGN

STRENGTH

A barrel is incredibly strong. The staves become a seamless series of arches side-by-side, capable of withstanding great force. Full barrels falling from high racks often bounce rather than burst. If properly maintained, they can last for decades. (A portion of our Eyrie Reserve Pinot Noir ages in barrels that are now 42 years old.)

MOVEMENT

The taper of a barrel makes it easy to move. One person can roll an empty one on its ends, spin it in place to work it around a sharp corner, or roll it end-over-end to squeeze through a narrow doorway. Full, a 60-gallon Burgundy barrel weighs about 650 pounds. Yet for all that weight, a full barrel can be tipped back and forth with one hand — very useful when gravity racking directly from the barrel.

PROTECTION

The taper of a barrel protects the wine inside from oxidation. The apex of the barrel’s arch, called the bilge, has a hole drilled in it – the bunghole.  The bunghole is used to fill and empty the barrel, and is stoppered with a bung. If the bunghole is placed straight up, any air inside the barrel will rise to the top, exposing only a small circle of wine to air. This air can be removed by pulling the bung, topping the cask, and replacing the bung. Frequent topping up prevents oxidation and vinegarization of the wine within. The barrel shape is so effective at preventing oxidation that the best small stainless steel drums are made in the bulged shape of a wooden barrel.

CLARIFICATION

The taper of a barrel also eases the process of clarifying the wine without filtration. The rounded bilge facilitates draining the clear wine off of the “lees.” (Lees are the yeast solids that have settled to the bottom.) Just as the shape of the bilge limits the amount of air contact at the top of the barrel, the bilge limits the amount of contact of the lees with the wine. This, and the ease of tipping the full barrel one handed, make it possible to put a tap in the head of the barrel and rack or bottle straight from the barrel. Traditional-style barrels still have a small bung low down in the front head of the barrel for exactly this purpose.