Fun fact! Drying grapes to make raisins reduces the water content and increases the proportion of sugar by weight. Click to read more.
Drying grapes to make raisins reduces the water content and increases the proportion of sugar by weight. For example, green grapes are 24% sugar, but that proportion increases to 60% by weight when the water content goes down.
Source: https://www.agmrc.org/commodities-products/fruits/raisins