grape concentrate
Grape juice that’s concentrated into a very sweet syrup, usually in the range of 60° to 70° Brix. In California and Italy, adding sugar to wine (chaptalization) is illegal, but grape concentrate may be added to boost the alcohol content or increase the sweetness of the final wine.
The New Wine Lovers Companion, 2nd Edition, by Ron Herbst and Sharon Tyler Herbst. Copyright © (1) 2003, 1995 by Ron Herbst and Sharon Tyler Herbst. Reprinted by arrangement with Barron's Educational Series, Inc.