Sweet wines can be made in many ways. The best use grapes that are rich in sugar and have had the extracted the water from them. There are three main processes used to remove the water from grapes used in sweet wine:
The botrytis method, a rot that shrivels the grapes and reduces hydration.
Natural drying method, warm temperatures and wind dehydrate the grapes.
The ice wine method, cold weather freezes out the water.
In some sweet wines fermentation stops naturally when yeasts convert sugar into a high level of alcohol and die leaving some sugar. The yeasts can also artificially be halted to produce a sweet wine with a low alcohol level.
Fortified wine is a wine that has had alcohol added (usually brandy) leaving some sugar unfermented. Fortified wine is distinguished from spirits made from wine, as spirits are produced by means of distillation, while fortified wine is simply wine that has had a (distilled) spirit added to it. Fortified wines include port, sherry, marsala and vermouth.