Wine Fermentation Question

Ok, So I've never made wine and don't really intend to. However, today at work someone was talking to me about beer brewing and asked how wine is fermented. I thought it was done with yeast and other people there said yeast was not necessary. So I thought I would come to this part of the board and ask....

Well, of course yeast is necessary for fermentation. Same as beer/mead/cider, etc. You don't always have to ADD yeast, though, as there is natural yeast present on the skins of the fruit. Most people choice to kill off the wild yeast and bacteria, and then add wine yeast, though.

Some places have good natural yeast. Just like beer brewing has been going on for centuries with natural yeast (think of the great wild Belgium strains that were used!), so has wine. Most of us, though, choose to have control over the characteristics of the finished products, so most of us add yeast.

Some wine is indeed fermented with the wild yeast that is on the grape skins naturally. YOU will need to pitch cultured yeast just like beer.

In order for fermentation to happen...there must be yeast. Yeast is the ONLY thing that can convert Sugar into Alcohol and Co2! SO! If they mean commercial yeast, they are partially correct...if they mean no yeast at all...dead wrong.

***Dang you Yooper!
I typted as fast as my fat little fingers could go!

I thought that yeast need be present for fermentation but I wasn't absolutely sure. The thought did cross my mind though that there was yeast in the skins. Listening to my uncle talk about their wine making experiences he said that they never put yeast in and they would mash the grapes and leave the skins in there. So that explains it, thanks a bunch Yoops and Kahuna. Now I can go back and properly inform them on how the process begins.