There are multiple types of sweet wine, including eiswein and port. To make a wine sweet, the fermentation process needs to be stopped before the natural grape sugar turns into alcohol completely. The higher the amount of residual sugar content, the sweeter a wine will be.
Eiswein is made from frozen pressed grapes and is one of the sweetest types of wine. Port is a fortified sweet wine for higher alcohol content and is also infused with fruit to increase its sweetness. White zinfandel is another type of sweet wine. This white wine is actually produced from red grapes without the skin of the fruit and tannin, which usually give red wine a bitter taste.