Definition - What does Heavy Toast mean?
Heavy toast (H) almost completely breaks down the chemical compounds which are present in oak, including oak tannins. This type of toasting is only meant for aging full-bodied and full-character wines.
Characteristics which are imparted by Heavy toast are smoke, fresh-roasted coffee, crème brûlée, toffee, molasses, butterscotch and many others.
WineFrog explains Heavy Toast
Even though heavy toast barrels are meant for full-bodied reds, it is recommended to use a blend of lighter toast barrels for part of the batch in order to obtain a balance of fruit and oak tannin on the wine´s impact and finish.
While these barrels can significantly add more complexity in the bouquet and flavor of wines which are aged in these barrels, they do not influence texture and tannin structure. This is because the true oak character, when toasted to heavy, are broken down including their ability to impart significant or noticeable tannin levels.