Forkulning

Toasting is a pre-treatment of the inside surface of the cask by exposing it to an open flame, where the wood toasts and forms a charred layer. The purpose is to activate the wood and alter its interaction with the spirit, which affects the color and aroma in the final whisky.

• Purpose

• Activate the wood's surface through thermal transformation of lignin and cellulose, releasing aromas such as vanilla and lactones and giving the wood's surface a porous network that influences the extraction of the wood's compounds.

• Process and char levels

• Internal burning of the cask walls creates a char layer. Levels are often designated No. 1 to No. 4; higher levels yield deeper color and more intense aromas as well as altered filtration of compounds between wood and spirit.

• Effect on whisky

• Color development: from pale gold to mahogany.

• Aroma and flavor are affected by the aromatic compounds released or formed during charring, such as vanilla, caramel and roasted notes; the flavor can gain sweetness, spice and nutty tones.

• Variations and use

• Toasting is commonly used for new casks, particularly in the bourbon tradition and in certain Scottish casks. The level and type of toasting affect the final style.