Hold the milk there for 30 minutes. Sous vide is amazing for this because of the consistent temperature. This is a step that can be skipped but I find I have a better set to my yogurt.
Cool milk to bellow 110 F.
Stir in the yogurt with live active cultures.
Transfer to clean quart jars or multiple smaller jars. Secure the with clean lids and bands or the no leak lids.
Heat the water to 110-115 F. Submerge the jars in the reheated sous vide.
Incubate the yogurt for a minimum of 5 hours or up to 24 hours. I prefer 24 hours for more of a tang to my yogurt.
Once time is up, remove the yogurt from the water bath and chill in the refrigerator over night.
Enjoy the yogurt with your favorite fruit or granola toppings.
Add the milk to quart jars or gallon zip top bags, submerge them into the sous vide and then turn on the water to 180. By the time the water has warmed, the milk is close to the 180 temperature. I use this technique when I want to step away from the stove and not boil my milk by accident.
To make the yogurt thicker in consistency with out adding thickeners, drain the yogurt in a strainer lined with cheese cloth or several layers of paper towels.
To cool the milk quickly, pour it into a large bowl that is set on an ice bath, string to chill.