I used a gallon of whole milk and a pint of heavy cream from my milk delivery service (south mountain creamery). It was labeled as pasteurized and homogenized.
I put 1.5tsp citric acid and 1/4 a veg. rennet tablet in and waited a couple hours and it still wasn't thick enough to cut. I saw another recipe that used 2 tsp citric, 1/2 a rennet tab and 1 tsp calcium chloride so I added the additional amounts and have waited another hour and it still hasn't done anything.
I think I got it a little too warm at first (around 95), I accidentally used my thermometer that reads low. It has been another hour at 91.
I'm pretty sure the milk isn't ultrapasteurized from the creamery so what else could be the problem?