I've read on the boards that too much rennet can cause bitterness, but that if you age the cheese that this will go away. I've also read that longer aging of cheeses made with vegetable rennets (or is it microbial rennets) will become bitter; so I'm assuming that the "aging to remove bitterness" is either restricted to calf rennet, or that the bitterness arises for different underlying reasons in the two cases.
Ok, what I'm more curious about is the bitterness that arises from too much starter culture. Does this develope with age? I've had one cheese that seemed to be slightly bitter, mostly on the finish. It's a cheese I've made a few ttimes, and it's never been bitter before. However, I aged this much longer than the others (took it over 100 days; which isn't huge long or anything), and I think I had used more culture than the other makes. I used to use 1 or 2 ice cubes of cultured Flora Danica, but I started useing 4 (about 1.2% volume of a 10L batch).
I've checked my notes, and see that I have a couple other cheeses made with 4 ice cubes of starter. These ones I've been aging for a long time (at about 6 - 8 months). If 4 ice cubes turns out to be too much culture, are these likely to be exceptionally bitter, as in unedible, or does bitterness due to over culturing peak, and then fade? I guess I could wait a few more months to find out, but I'm worried now.