We’ve discussed how seasoning of oak affects tannins and the flavors of oak barrels, but that’s only part of the story. The biggest impact on the flavor of the wine can come from the actual manufacture of the barrels. In order to be able to bend the oak staves into a barrel shape, the insides of the staves are heating over a fire. This heat chars the wood and creates complex chemical reactions.
One reaction is akin to the Maillard reaction that causes the browning of meats and vegetables. This reaction creates compounds that add sweetness, as well as flavor, to a wine. Barrels can be lightly toasted or heavily charred during the manufacturing process, and each increase in the level of toastiness translates into a more assertive flavor in the finished wines.
There has been a lot of discussion over the past two decades regarding the uses of oak, and the specific toast levels ideal for specific wines. This point of contention has been one of the pivotal issues that have separated the traditionalist school of thought from the evolving Modernist camp. What has become apparent, and it has taken two decades simply because these wines generally need significant aging to tame the tannins and toast imparted by these heavily toasted new barrels, is that even after two decades many wines have been, and remain, dreadfully over oaked.
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So winemakers have erred by over-extracting their wines and then putting them in oak barrels to hasten the softening of those tannins. Of course wood barrels have plenty of tannin to contribute to the wine, especially if it is new barrel. In order to moderate the effects of the oak, as far as tannin contribution goes, winemakers have opted for heavily toasted barrels. In general, the heavier the toast, the lower the level of tannins contributed by the barrel. And thus was born the “recipe” for a modern wine, packed with fruit, oak tannins, toasted oak derived flavors, and a winemaker’s imprint while lacking much typicity.Simply put the flavors of the grape, the soil, the style of wine that sets one region’s wine apart from another.
The effects of heavy toasting go far beyond tannins, as the heavy charring can reduce the coconut note American oak imparts in wine. At the same time it increases the effects of the Vanillin in the wood and creates chemicals that recall dried ginger, cloves or allspice, for example, not to mention the actual notes of toast and char present in many wines.
While only the staves of a barrel need to be toasted during manufacturing process, many winemakers now order their barrels with toasted heads. The head is the flat end panels of the barrel. By toasting even this part of the barrel, winemakers truly maximize the affects of their new toasted oak barrels.
While oak barrels are generally associated with the ageing of wine, many producers also choose to barrel ferment their whites, and even some reds. Counter intuitively this process can result in a wine that features a more subtle integration of wood tones.
The yeast cells active in fermentation can not only transform some of the vanillin released by the wood into a non-reactive form, but they can also physically bond to some of the more assertive elements that the wood contributes to the wine. As these yeast cells die and fall out of suspension, creating the lees of the wine, they take some of those flavoring elements and tannins with them.
It can all be very confusing but you can find a brief breakdown of these flavors below. By helping you to become familiar with the aromas and flavors of the various toast levels commonly used in wine barrel production, this guide can help you find out what you like in a wine.
Spanish wines have made a name for themselves by using American oak, though French oak is gaining ground with each passing vintage.2000 Lopez de Heredia Bosconia Rioja
Lopez de Heredia is one of the most traditional producers in Rioja. They are committed to using American oak for their wines, and in fact, produce their own barrels exclusively from wood grown in the forests of Appalachia. These are wines that are balanced, perfectly integrating the notes contributed by their wood ageing.
2005 Pesquera Crianza Ribera Del Duero
Alejandro Fernandez established Pesquera in 1972 with an eye on becoming the benchmark producer for the region. His firm conviction that American oak is a better partner for Tempranillo has lead him down the path to becoming not only a benchmark for Ribera, but for all of Spain.
Oak derived flavors and aromas.
Heavy Toast contributes caramelized, smoky, burnt and toast flavors
Heavy toast French oak imparts cinnamon, ginger and clove with undertones of crème brulee, bitter cocoa, charcoal and roast coffee character. French oak often develops a very cedary aroma.
Heavy toast American oak imparts a heavy campfire/roasted coffee note with a strong vanilla signature
Heavy toast Hungarian oak impart a heavy vanilla note with spicy, molasses undertones
Medium Plus Toast imparts aromas of honey, roasted nuts, toasted bread, and baking spices. They lack the black spice and char tones of heavy toast yet remain very assertive.
Medium Toast imparts more spicy, woodsy tones to the wine and the effects are perceived more easily on the nose then on the palate.
Medium toast French oak imparts cigar box, cedary, creamy tones to the wine with toasty notes
Medium toast American oak imparts cafe au lait and coconut tones with a strong vanilla signature
Medium toast Hungarian oak imparts a vanilla note with spicy, earthy undertones
Light Toast raw wood, coconut and dill
Light toast French oak imparts notes of vanilla, raw wood shavings and sweet caramel notes
Light toast American oak imparts coconut and dill notes with raw wood tones
Light toast Hungarian oak imparts a light vanilla note with spicy, herbal undertones
Aromas associated with oak
HERBACEOUS: Weedy, Dill, Mown Hay, Menthol, Grass, Tobacco.
WOODY: Cedar, Sawdust, Pencil Shavings, Sappy, Green, Pine, Tar, Resin.
SPICY: Clove, Cinnamon, Coconut, Vanilla.
Aromas that can develop in oak during the toasting process.
SMOKY: Barbecue, Wood Smoke, Burnt Sugar.
SWEET: Brown sugar, Barbeque Sauce, Maple Syrup, Butterscotch, Molasses, Honey, Toffee, Marshmallow,
CREAMY: Lactic, Butter. Cream
YEASTY: Popcorn, Cookie Dough. Baked Pastry Dough
ROASTED:, Graham Cracker, Toasted Bread, Coffee, Cereal, Caramel
NUTTY: Hazelnut, Walnut, Almond,
SPICY: Nutmeg, Dried Ginger, Cigar Box