Take care of your sanitation w/ your press. I just rinse my apples in lukewarm water. Either use campden/k-meta or sodium bisulfite to shock the wild yeasts and other bugs. You can also do a low temp(145 to 150*F if I remember right) pasteurization before pitching yeast. I haven't had any problems doing any of these. Do you have an apple crusher/grinder? It sure improves your yield. I have an old hand crank meat grinder, and it helps. It is a lot of work, though, I have to quarter the apples to get them in the grinder.