Also know as Brett it is a fungus that in small amounts can add flavor to wine but just a touch to much and you get a "corked" wine that smell of wet cardboard or dirty socks.
Go to the wineries!.
Find out which wineries offer complimentary tasting. However, it is a courtesy to buy wine after you have tasted it.
In Napa Valley the wineries typically charge between $10-$20...
Not too sure what your question was. The answer would be 100% wine in grape wine. But if you are asking for alcohol level, its 11% -15%, depending on the wine.