I live in Thailand, but while I was in the States last month I purchased some supplies to make feta... Bioren rennet tablets, Lipase powder, and Danisco MT1 culture. Everything was stored in the fridge until I returned to Thailand last week.
All of the recipes that I've seen in print and in videos specify a set time of 1 hour to get a clean break (a couple specify upwards of 3 hours). I just made a batch of feta, but it took a full 5 hours to get a clean break. After the first hour, it had basically done nothing and still looked like liquid milk. After 3 hours, it was about the consistency of yogurt.
I don't know how good the milk quality is here compared to the States or Europe as far as cheese making goes. I made a two gallon batch and used 1/4 tsp of the culture, 1/4 tsp of lipase, 1/2 tsp of 30% calcium chloride solution, and half of a rennet tablet (which should be good for 2.5 gallons). It didn't take much time to bring the milk to 86 degrees since the room temperature here is almost that high during the day. Once I got it up to temperature, it pretty much stayed constant for hours without adding any additional heat.
The cheese is currently hanging in the cheesecloth, but I wanted to know why it's taking 5 hours to set? What variables are the most important to set time? Should I try a different brand of milk?