Chapter 21

The Role of Oak in Winemaking

Inspecting New Wine Barrels

If new barrels are not used immediately after delivery, they are often left with the plastic wrapping and kept in a location with 65 to 75 percent humidity, until they are used (Figure 21.5). The barrels should be stored at a low temperature of approximately 10 degrees C (50°F) in a location isolated from direct sunlight, drafts, or temperature fluctuations to prevent them from drying out. Many wineries as part of their quality control program visually inspect new barrels for defects and water test all barrels for leakage before using.

Visual Inspection

When a new barrel arrives at the winery remove allwrapping material and inspect the exterior of the barrel. The barrel should be smooth and well sanded with no gaps between staves. Check for cracked staves, particularly in the bilge area. Cracking of staves at the bilge is often a sign that the wood was not heated sufficiently or properly prior to bending.

Water Test for Leakage

There are three common methods used to test the barrels for leakage. When testing for water leakage water quality is perhaps the single most important factor in maintaining sound cooperage. If heavily chlorinated water is used, a charcoal filter is strongly recommended.

Pressure Leak Test

After the visual inspection of the barrel the next step is to check it for leaks. Lay the barrel on a testing rack where it can be rotated and add 11 to 19 liters (3-5gal) of water to the barrel. Replace the bung and rotate the barrel to ensure that the entire inside of the barrel is wet. Attach a pneumatic fitting to a hard rubber barrel bung.

Hot Water Soak

Another approach used by wineries to test new barrels for leakage is to use hot water (50°C, 120°F). Following the inspection, add 23 liters (6gal) of hot water to the barrel, the barrel is rotated to coat the inside, and the bung is placed gently back in the bung hole, only tight enough to form a seal.

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