Yeast

Question

Rabbi, I saw a question about yeast and what it is made of. Yeast is an living organism that occurs naturally...it's waste product is alcohol. Grapes and grains ferment when the yeast that grows naturally on them or is added to them feeds off it's sugars and releases alcohol - this is how we get wine, beer, vodka, rum, etc. Yeast is what also makes our bread rise. Sourdough bread has no yeast added, but allows the naturally occuring yeast to ferment and raise the dough. As far a pesach is concerned I though that there are two types of prohibited foods: Chametz and Seor. I was explained that Chametz is one of the five grains of Eretz Yisrael that has come into contact with water for more than 18 minutes without being baked, and Seor is leavaning agents such as yeast (and is not to be confused with barley). Could you clarify the difference between Chametz and Seor? Also (I apologize for the long message) how would you classify Kamut? Kamut is a grain native to Egypt, looks like wheat, but has a bigger grain. Perhaps this is one of the five grains! Kamut is now widely available in healthfood stores across the country and I would like to know if this is Chametz, Kitniot or neither. Kol Tuv and Chag Kasher v'Sameach, Aric