I bought this product and then that same weekend realized I could do the same thing by putting jars of culture in hot (110f) water on the bottom of a Coleman cooler & closing the lid for three hours. I made a gallon of home made yogurt without using anything more fancy than a candy thermometer. This product does do as it is advertised, but most of the work it does is just an incubator. My first batch turned out ok but my second didn't thicken (possibly my error there though).