This is my first time making wine and I'm ready to bottle my first batch. It is made from muscadine grapes and it tastes a little bitter. My wife and I prefer dry wines but I think we may need to sweeten this a little. I'm aware that I need to stalize the mixture to prevent a secondary fermentation, but I have no idea how much sugar I should add. Are there any rules of thumb as to how much sugar should be added for each gallon of wine?