Typically 4-12 days but it depends on a lot of factors:
Fermentation temperature. Higher the temperature faster the fermentation is (but beware of the off-flavors produced in yeast fermented at above 25 degrees Celsius) Yeast dosage. although 1gm/liter is recommended. Increasing it to 3gm/liter can produce wine in 2-3 days (50% reduction in time) Availability of yeast nutrients. Grape and fruit juices don't have enough natural proteins for the yeast to multiply fast. Adding 0.5-1gm per liter of yeast nutrient is sufficient to establish a healthy yeast colony and fast fermentation. Mead is notorious for being slow to ferment and produce nail polish like off-notes because of a lack of nutrients. Sugar concentration: 18-25% w/v of sugar concentration is ideal for fermenting with wine yeast. However higher the concentration, the more time it will take for the yeast to finish its job and produce ethanol.