Blue cheese gets it's characteristic look and tang from being infected with penicillium roqueforti. This is an additional to the inoculations used to acidify the milk--in other words, you use both. There are three ways to inoculate a loaf of cheese to cause the growth of roqueforti, and thus make blue cheese:
- Own a cave where it occurs naturally. If you have one, I'll be over for dinner :)
- Purchase the pure strain from a cheese making shop and use it during the make
- Puree and add a cheese that already has roqueforti in it
Regardless, since roqueforti is aerobic, meaning it needs oxygen to survive and multiply, punching holes in the loaf is a good thing to do regardless. After the holes were punched and the inoculation added, the loaf was wrapped in cheese cloth to encourage a wetter, more humid surface without coating it in wax. The wax would prevent oxygen to penetrate the cheese, thus preventing it from turing blue.
As you can see from the price tag of the commercial blue I purchased, this could turn into a really good deal. The total price tag for making one pound of home made blue cheese could potentially be less than $5.00, which is a quarter of the cost of many blues in decent cheese shops. Now, in all fairness, the blue I'm using for this is absolutely delicious and will probably be ten times better than what I can make, still I suspect it might turn into a good deal.
P.s., the first two photos are of the blue cheese I used to culture the roqueforti from, not my own. If I can ever make cheese that good it'll *have* to be my day job :)