I live in Wa and get my Raw milk here. I use it to make kefir and I am told that during the fermentation process all the bad bacteria is killed. I love the taste of the kefir after its been in the fridge and mixed with stiva and cinnamon. I cant wait to get to the stage where I can throw in some rasberries and make a smoothy out of it.
My first batch of home made Yogurt is in the fridge now. Yogurt however doesnt kill all the bacteria like Kefir as far as I know. You have two options either flash Pasteurize your raw milk by bringing it up to 180 degrees F (which kills the good stuff too) or find a good quality source. I dont see the point of flash pasterurizing raw milk as its more expensive. I just bring mine to just over a 100 degrees then add my starter yogurt. My first batch looked great and I cant wait to dig into it.
this is how I make my yogurt, Only my first batch, I waited 4 hours, unhappy with how think it was I put more hot tap water in the cooler and waited another 4 hours and it came out perfect. Also to note, I add a little powered milk to as well becuase I like my yogurt very thick.
*edit after writing this post, I went and tasted my yogurt and it taste very simular to the greek yogurt I used to start it. Which is pretty good considering I didnt add any sugar. Its nice and thick 🙂
Also, I remembered that I read this which is important if your using raw milk to make yogurt.
Furthermore, due the natural presence of beneficial bacteria in raw milk which are likely to eventually out-populate the strains in your desired starter, your yogurt starter will degrade over time. For this reason, it is necessary to maintain a pure seed starter or to be mindful of the desired quality of your yogurt and to purchase new starters to periodically refresh your old starter. This is generally not necessary when making yogurt from boiled milk.