How do I decide whether to make a mother culture or use direct set packets?

For most purposes, we recommend using the direct set cultures. When you use them, you are sure of the amount of culture activity you are getting. When you make a mother culture, you are exposing the culture to the freezing and thawing process which affects the balance of bacteria. Mother cultures are fine if you are making cheese every 2 -4 days. They will last for a month or so, but the problem is that even when they are still alive, they are not necessarily in optimum condition to out-compete other bacteria that may get into the milk.