i like nonfat yogurt, so ours is made from skim milk. one glass jug of milk made these two large parfait jars full. i just used the last 6 oz. of the yogurt we had bought to make this (but subsequent batches will be made with 6 oz. of the last batch's yogurt). the only pieces of "equipment" required are:
-a candy thermometer
-a small cooler
-jars for the yogurt
the ingredients are:
-milk (skim or otherwise)
-honey (optional- see note below)
-6 oz. yogurt
1. heat milk over medium high heat until temperature reaches 180 degrees F. remove from heat.
2. when milk cools to 125 degrees F, stir in a glug of honey and a splash of vanilla.
3. fill a small canning jar (i use one like i used to hold the granola bars) with very hot water + lid and place in the cooler to warm it up.
4. when the milk cools to 110 degrees F (and not before, because any higher temperature kills the live cultures), add the 6 oz. of yogurt. whisk well.
5. pour into jars and place in the cooler with the small jar (my cooler will just fit the 3 jars together inside).
6. let sit for 5 1/2-6 hours and then refrigerate.
as i've gotten to know this process better and better, i've learned to set the timer appropriately to remind myself to check the thermometer throughout the process. depending on the weather, steps 1-5 take somewhere around an hour, but there is barely any hands on time. i write down the time to refrigerate, so that there's no confusion.
this process was easier than i thought, and it results in some good yogurt! next time i will be able to use this yogurt as my starter, so it will truly be zero-waste! yay!
update: april 15, 2015 our entire tribe is in love with this yogurt! first of all, the tubs that are not being added to the recycling each week are worth a few jumps for joy!! that thought makes me so happy! in addition to that triumph, is the amazing taste! some of us didn't eat yogurt very often before, and now all of us are eating it almost every morning. the question comes up again and again, "what's in this again?" just skim milk, honey and vanilla (plus a little of last week's yogurt that was made of those three things as well)…this yogurt will be on repeat for a long, long time. can't believe i didn't try this earlier!
update: october 19, 2017 i am still making this yogurt about once a week + eating it every morning with bulk granola. now i don't add vanilla or honey, because we have adjusted to the taste without it + don't need any extra sweetness.