are you talking about fresh mint leaves or something like a peppermint flavoring? I was thinking about possibly using some lemon balm in a brew, but i don't have any experience with mint or lemon balm.
[ame=http://www.google.com/search?q=mint+site%3Ahomebrewtalk.com&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a]mint site:homebrewtalk.com - Google Search[/ame]
I was planning on using fresh mint leaves. Do you think the leaves contain any sugars that could cause overcarbonation when mixed with the priming sugar?
I've used fresh mint in a blonde before. It gives a greenish taste to the beer. Exactly what I was looking for. If you want peppermint flavor, I suggest extract or mint tea.
So if you are looking for a green, "vegetal" mint flavor, mint leaves work for what you are describing.
If you want the flavor of, like a mint candy, or a peppermint cane, or mint bubble gum, then you might want to consider tea or extract, NOT fresh leaves.
As far as priming, no, mint leaves should not contain any significant sugar that would affect priming for carbonation. Mint extract, however, might - you will have to check the bottle of the specific extract if that is what you use.