I agree with the above comments. Reduce acidity some by either less culture or less ripening time. And, cut back the rennet to 1/4 tsp to 1/2 tsp at most. You may find that you don’t have as firm a curd with less rennet, but once you get the “clean break”, the curd is set and now treat it very, very gently when cutting and initially stirring it. With a little cautious stirring the curd will start to firm up nicely. I only say this because this was a mistake I kept making—thinking that the curd needed to be set up a lot more than it really should be. So, I tended to try to get a firmer curd with more rennet, and ended up with bitter and drier cheeses. Then, I visited a local Artisan cheesemaker and saw what the curds were like when he cut them and began foreworking them, and I saw that his curds were much “softer” than mine. Since then, I’m getting better cheeses (and better yields).
