Just got back from a wonderful business trip to Portland Maine, visiting ForeFlight. Making more probiotic yogurt tonight because I ate up almost my entire stock on the trip. (It didn't help that we got stuck in a blizzard while there, but that turned out to be really fun.) The food in Portland is amazing!
The pot of boiling water is for sterilizing the growth medium, in this case 2% organic grassfed milk+raw sugar. After the milk is boiled (repastuerized) and cooled I inoculate it using a 10 strain probiotic blend from Safeway. I tried a bunch of probiotics before finding this particular brand, which seems magical for me. Without this extremely strong yogurt I have no idea how long it would have taken my gut to heal after the antibiotics I had to take in 2015.
Yogurt making like this is tricky. Early on, around 30% of my attempts failed in spectacular ways. These days my success rate is almost 100%. Sterilization of basically everything (including tools, spoons, etc.) over and over throughout the process is critical to success.