When I was hooping the quark the next morning for draining, Benjamin and I noticed an off flavour and an elevated pH. We went ahead and drained it, but unfortunately it proved to be inedible. The caerphilly was in the salt brine at this point, and when we looked at it there was definite puffiness, which is normal in swiss cheeses with the production of gasses inside, but shouldn't be happening in this cheese. So both batches of cheese that I made that day were unsuccessful.
If it were only one, I would assume that I didn't sanitise my equipment properly or was careless with my ingredients at some point. But the fact that it was both batches, made in different vats and with different recipes, indicates that something was wrong with the milk.
Now, this happened to be milk that we had delivered that morning from another farm. We started buying milk from them a few weeks ago (due to our drought), and up to now have had no issues with it. They have wonderful milk for cheesemaking and we have been very happy with it. We're not sure exactly what happened to compromise the quality, but it's really unfortunate to have wasted so much time and energy on nothing.
You really can't make bad milk into good cheese, no matter how hard you try. It is so important to have clean, fresh milk, and so discouraging to discover otherwise. It was my first disastrous day in the cheese room, but I suppose it had to happen at some point. There is sometimes no way of knowing what's really going on with the milk until it's too late. For every award-winning cheese, there are multiple failed batches that are never spoken about, simply because that is the nature of cheesemaking.