Avril, Bob's suggestion for 200 Easy Cheesemaking Recipes is a good one. Concise and clear info with good technique explanation, useful tips and illustrations.
I apologize if I went into jargon land; I really try not to do that, especially if I know there are people on the thread who may not know what I mean. You will find a lot of jargon here, but most of it is just short names for cultures (Geo and PC or Fl-Dn instead of Geotrichum Candidum, Penilillium Candidum and Flora-Danica), shorts for materials (CalCl2 instead of Calcium Chloride), or short for situations (temp for temperature, RH for Relative Humidity and pH when people use pH meter). You will also see some shorts for processes (such as floc for flocculation, multiplier, heavy brine/saturated brine etc.). The rest are proper words, though some may be unfamiliar phrases (such as "poil de chat", "slip skin", "toad skin", Morge, Mocasse, ammoniation, lipolysis, proteolysis, DVS/DVI etc.) No one expect you to know all of these things. It's not just a newbie thing but also something you may run into when switching from different types of cheese. We all come across them but I think I gave you the most common ones here and you are always welcome to ask (you can PM me too ...Eh, I meant, Private-Message me). Don't get overwhelmed; it's really about 15-20 phrases that everyone here repeats and by doing so they are able to pin-point a process, an error, an exact measurement or specific ingredient -to help you perfect your cheese in a way that most of these recipe books really can't. Of course, it's also just being lazy; who wants to spell out Penicillium Candidum every time?
OK, let me explain my sentence:
Culture arrives in sachets that are good to inoculate huge amounts of milk at once. As Bob mentioned, cultures (unlike salt, rennet or Calcium, or spices in cooking and baking) don't double as the milk quantity doubles. Generally for small home-made batches you would use the quantities I specified. If you go over 12 gallon per batch, it is safe to assume you are using a large vat / doing large batches. In this case it is more cost-effective to switch from teaspoons to the less wasteful unit measurement that is printed on the sachet (which was meant for commercial cheesemakers).
For example: If you the sachet reads "50u", it means that the entire package can set 500 liters of milk. Say you are doing a 50-liter batch (13 gallons), simply use 1/10th of the package instead of measuring in teaspoons. Am I more clear now?
The other thing I said about the milk was that if it was pasteurized to death (HTST or UHT or Ultra Pasteurized -phrases that are often actually on the milk carton, not a Cheeseforum jargon), then it is safe to assume that no significant organisms have survived this violent pasteurization process. You can therefore give the milk a little more culture to start re-growing life in it in quantity that makes up for the natural bacteria that was killed off in pasteurization. If the milk is raw, you want to use less culture; give it just a little kick and let its natural bacterium and flora speak for itself.
And that's my problem with these recipes... they accidentally make people think of rennet, calcium and cultures as if they were spices or food substances, but they are far from it. They merely control the development of living organisms and how they affect the development of flavor, texture, and aroma in cheese. One cannot just increase rennet to get harder coagulation; it will make bitter cheese. One cannot increase cultures to make the process faster; cultures will acidify at the same exact speed, but with too much too quickly, the cheese will be dry, crumbly, sour and won't even be able to melt. Cheesemaking is closer to gardening than it is to cooking if you think about it.
Always remember in cheese that you are manipulating life, not substance. It's really incredibly magical if you think about it!