Chapter 21

The Role of Oak in Winemaking

(book excerpts)

The oak wine barrel is one of the most recognizable symbols associated with wine. There are two ways that wine benefits from its contact with oak. First, oak wood is composed of several classes of complex chemical compounds, each of which contributes its own flavor or textural note to wines. Second, controlled oxidation (i.e., micro-oxygenation) takes place during barrel maturation due to the transference of oxygen from wood to wine. This very gradual oxidation results in decreased astringency and increased color and stability. For many fresh and fruity styles of wines made for early release and are meant to be consumed young, oak barrels are seldom used. In the production of premium wines such as those with good body, complex flavor, supple texture and long finish, oak barrels are often employed. The primary sources of oak for production of wine barrels are from the United States, France, and Hungary. Barrels are constructed in cooperages. Barrel aging normally takes between 6 to 30 months (shorter aging times for white wine, longer for red wine). A wine with higher concentrations of phenolic compounds will need longer aging time to soften the tannins. For commercial use, barrels are considered used up (described as neutral) after four to six years. Cleaning and sanitation procedures are very important in extending the barrel' s life, especially in the case of the well-known Brettanomyces spp. Use of barrels adds to the cost of wine. The expense includes not only the cost of the barrel, but other factors such as cleaning and sanitation, barrel storage, maintenance, barrel exhaustion, the loss of wine due to evaporation, leakage, and sometimes spoilage. Oak treatment normally occurs when wine is fermented and/ or aged in barrels, but increasingly oak alternatives, chips, pellets, staves, etc., are used to add oak influence to wine in other vessels, e.g., stainless steel, plastic tanks.

Click on the following topics for more information on the role of oak in winemaking.

Topics Within This Chapter:

  • Fundamental Role of Oak Barrels
  • Compounds Extracted from Oak
  • Lignin
  • Polysaccharides
  • Lipids
  • Hydrolyzable Tannins
  • Best Wines to Age in Oak Barrels
  • Sources of Oak
  • Coarseness of Grain
  • Flavor Profiles of French, Hungarian, and American Oaks
  • French Oak
  • American Oak
  • Hungarian Oak
  • How Wine Barrels Are Made
  • Staves
  • Seasoning of Oak
  • Natural Seasoning
  • Kiln Drying
  • Barrel Raising
  • Barrel Toasting
  • Convection Toasting
  • Chiming
  • Inspecting New Barrels
  • Visual Inspection
  • Water Test for Leakage
  • Pressure Leak Test
  • Hot Water Soak
  • Barrel Cleaning and Sanitation
  • Barrel Cleaning
  • Barrel Washing Systems
  • Barrel Sanitation
  • Hot Water
  • Steam
  • Ozone
  • High Power Ultrasound
  • Storage of Empty Barrels
  • Short-Term Dry Storage
  • Long-Term Wet Storage
  • Post Rinse Following Storage
  • Life Cycle of Barrels
  • Resurfacing Oak Barrels
  • Winemaking with Oak Alternatives
  • Dosage Rates
  • Oak-Alternative Products
  • Oak Powder
  • Oak Chips
  • Oak Blocks
  • Tank Staves
  • Barrel Inserts