The Muscat grape is the oldest grape known to man. It was surely the first grape made into wine. It gains one of the highest sugar levels of any other grape there is. Fermentation takes place when the yeast on the skin of the grape contacts the sugar inside. That starts a chemical reaction where the yeast turns half the sugar into alcohol and the other half into carbon dioxide, which goes into the air.
However, once the alcohol reaches 17% or higher, the yeast dies off and whatever sugar isn't converted remains in the wine. So, some 8,000 years ago when enough grapes were stacked on one another to start fermentation, the resulting liquid was alcoholic and sweet. Ergo its popularity.
While this all may sound fine, it can also be a problem. When alcohols reach that level, they can turn bitter after a short time in the bottle. Fortunately, guys like O'Neill Vintners, makers of Backstory, know how to deal with that issue. They train the vine's own leaf structure to grow over the grape cluster, shielding it from the sun and reducing the sugar.
The result is a balanced grape with enough sugar to be interesting, but not so much alcohol to be disturbing. With coconut cookies or pineapple pound cake, it represents a yum factor times two.