The final step is to incubate the liquid for approximately three to six hours at 110 Farenheit (44 Celsius) plus or minus 5 degrees (3 degrees Celsius). We recommend using glass jars with lids for the yogurt, but lidded plastic will also work. There are many ways to achieve the stable temperature that is required but we have found that a cooler filled with the proper temperature water is a very easy solution. The water level should be kept below the tops of the containers to ensure that they don't start floating around. You should have all of this this prepared in advance so you can place the jars in right after mixing.

Monitor the temperature so that it doesn't drop more than 5 degrees Farenheit (3 degrees Celsius) in relation to the target temperature; to do so you can simply add hot water as necessary. If you put the cooler in a warm place, you may only have to monitor the temperature once every hour or two. Do not disturb the yogurt during this period. After about three hours but maybe as long as six, the culture will spread throughout the liquid and the yogurt will coagulate. Note that some water (whey) may collect at the top. On occasion, gently tip the jar(s) to test and once the yogurt has coagulated, remove it from the incubator and refridgerate. Congratulations, you've made your own delicious yogurt, and it will last for about two or three weeks if properly refridgerated.