What is Relationship between sugar concentration in wine grapes and alcohol concentration of the wine made from the grapes?

Take the sugar level at time of harvest and times it by .55 to get the alcohol level. 24 brix of sugar equals 13.2%. So the higher the sugar the higher the alcohol. This is why some Zinfandel will have a higher alcohol level do to the fact that they can easily reach 29-31 brix.