Hi!
We have been making yogurt for several months now...we have put in either good vanilla extract or a whole vanilla bean. 1 tsp of extract is added after temp is reached and you are putting mixture into maker. We add 2-4 tsp of raw sugar too, to decrease tang. If we do the vanilla bean method, we include it during the whole milk heating process. We slit the bean lengthwise and toss it in.
We have also used natural flavorings (not extracts) such as raspberry and banana, along with a little raw or turbinado sugar or maple syrup - a friend always uses honey and says that is great too.
I think I want to make a batch now!
Denise