I inherited a ronco dehydrator from a family friend. I tried to use it today to make yogurt and after about 4 hours the yogurt *looked* just like beautiful thick yogurt. I checked the temp of it though and it was 122. Did I kill all of the good bacteria? About half way through the cycle I closed the vents on the top becuase a spider fell into my yogurt! Should I have left the vents open the whole time? Would that have kept the temp right? Prior to closing the vents when I checked the temp it was around 108.