If a barrel is described as Virgin or First Fill, then we are talking about brand new barrels that haven’t had a spirit aged in them yet.
Typically made of new American Oak or new French Oak, the wood from these barrels will have a large impact on the flavour of the whisky. This is compared to the wood in Second Fill barrels, which will have less of an impact on the whisky.
The wood from Virgin or First Fill barrels will impart a lot of sweetness and spice into the whisky, as well as a strong oak flavour. The whisky will also pick up a lot of the vanillin from the wood, which adds a creamy and vanilla–like sweetness to the whisky. The whisky will also gain a lot of colour from these barrels.