Nuance is a light long toasting, designed to maintain freshness of fruit and linearity on the palate. Special toast emulates the style of 19th century coopering, when coopers did not flip the barrel during toasting but rather left it on the fire until it developed distinct aromas of fresh bread, as if cooked in a brick oven.
Double is a toast just as the name implies, toasted twice—to Nuance levels in the morning, and after cooling are warmed and then toasted to Medium in the afternoon. This gives volume and brings in some sweet oak notes, without dominating the wine.