One thing to keep in mind with all the yogurt making machines- even the "Cadillac" Yogermet (sp.?) maker, is that they are "dumb"- they have no thermostat brain, just a constant power heating element. Thus, depending on the room temperature or even the random variation in build of the yogurt maker, the resulting incubation temperature may fluctuate wildly from the ideal target, by as much as +- 10 or even +-15 degrees F in my experience. Being a perfectionist, and for that matter, an engineer (lol), I couldn't stand this randomness, so what I did was drill a small hole on top of the yogermet container and insert a stick thermometer in the mix, and then I plug the yogurt maker into a lamp dimmer switch ($20 at Linen n' Things) that allows me to fine tune the amount of power to the heating element so that it settles right in the optimum 107 F or whatever target temperature. Anyway, this resulted in completely consistent yogurt for me every time.