The toasting phase is a key stage, mellowing wood’s harsh tannins and mitigating raw oak flavors.

Over time, SEGUIN MOREAU came to differentiate between the firing of the barrel at the tightening stage and the oenological toasting of the barrel: bousinage. Bousinage dramatically changes the wood’s physiochemical composition and physical structure.

Lignin, cellulose and hemicellulose (wood sugar) are essential components of oak—their chemical bonds are broken during toasting, leading each compound to break down to simpler substances. Tannins also go through a similar process, emitting free ellagic and gallic acids. With enough heat, the tannins can be completely destroyed.

Hemicellulose begins to release its basic sugar compounds, which contribute to toasty aromas. Lignin breakdown leads to the creation of vanillin, oak’s signature flavor, as well as syringaldehyde. At higher temperatures, lignin creates volatile phenols, such as guaiacol, lending smoke notes.

Toasting aroma descriptors: 

Vanilla, vanilla bean, caramel, dark chocolate, milk chocolate, cocoa, toast, coffee, mocha, toffee, toasted almond, roasted nut, allspice, cinnamon , cardamom, butterscotch, clove, spice, smoke, crème brûlée, tobacco, cigar box, coconut, French vanilla, brown sugar, nutmeg, honey, baking bread, cream, white chocolate, hazelnut, espresso, roasted coffee bean, toasted marshmallow.

During the toasting process, everything is under control—including color, smell, temperature, time, flame intensity and inner stave texture. The coopers have to adjust for daily variables such as humidity, outside temperature, time of day and climate inside the cooperage.

With the above parameters, SEGUIN MOREAU’s defined toasting levels help develop the exchange between the wine and the wood, depending on the grape variety, terroir and oak species.

Toast Level





Light L Earthy, milder wood characters, complex baked aromas. Reduced vanilla component as toasty, fresh flavors begin to develop. Wines requiring a minimum of aroma enhancement but benefitting from increased tannins.
Medium M Complex and toasty aromas: vanillin, coffee and freshly baked bread. Round, sweet oak flavors and notes of spice, butterscotch, vanilla, caramel and chocolate. Fuller-flavored wines, which can accept balanced oak impact on nose and palate.
Medium Long (Burgundy Style) ML Hazelnut and spice with more minerality and delicate oak. Soft structure with smoother tannin profile, due to slower, controlled release of oak notes. For wines not requiring significant oak tannin contribution yet suited for barrel aging.
Medium Plus M+ Vanilla bean, hazelnut, spice, oak lactone and brown sugar. Greater depth of toast brings round flavors: intense vanilla bean, chocolate mocha, spice, integrated oak tannins. As with the M, ideal for fuller-flavored red wines, where the wine has its own richness and can accept a full yet balanced oak impact.
Heavy H Smoky characters, touch of black pepper, diminished oak lactones, espresso note. Smoky, roasted coffee, with a reduction in sweet roasted flavors. Best for a full impact of complex aromas. Lesser contribution of tannins to wine structure.
Toasted Heads (the heads of a barrel are 30% of the total oak surface area) TH Reduces oak lactone and dusty wood characters, more even pickup of toast. Lessens structural contribution of oak tannins and contributes an increase in the toast characters. Works well for medium weight white wines. Also useful in reds which have sufficient tannic weight. Allows for more consistent characteristics.