I wonder if there is a detailed sort of 'Microbiology for Dairy' book that I could read.
Yes, but it's not going to tell you things in a clear way. You're looking for a description for how to go about culturing yeasts, molds, and bacteria, how to run a basic lab, how to use it in cheesemaking, etc. Right? I'm working on this for my book series. In the meantime, google, or ask here.
I'll e-mail you a few things.
Just spent too much time googling it's growing conditions.
For roqueforti? For what, growing on slants, or for a fermentation system? If you want to propagate, there are different approaches based on your needs. You can use solid state fermentation or liquid fermentation, and then from there, either do it in batches or in a continuous system. See how you read all that and have no clue what it all means? That's what I'm talking about, all the books are like this. You can't get a straight answer because the best answer really is "it depends".
Essentially, you need a C-N ratio of around 10 (this can vary drastically, being as low as 5 and as high as 20), and trace elements for food. I could invent a custom "bread" recipe if you want. This would likely be the easiest approach. To make croutons from a special bread, and then inoculate it with roqueforti, and then crush it all up and use the powder. That's likely the easiest thing to do at home. beyond that? You need acidity of 5.0-5.5, temp of 60-75F, and high oxygen availability (you would need to filter air and have it flow through the chamber, or vent and introduce oxygen somehow. Not too hard to do... think custom lid on mason jar with a few vents attached to hose.
How does one choose?
Customarily, based on the needs of:
- Color of strain in cheese, from white to green to deep blue to sky blue
- Initial proteolytical capability
- Aroma formation
- Enzymatic capability for lipolysis
- Enzymatic capability for catabolism of amino acids/peptidolysis
Meaning it has to match your cheese and shelf life and market goals. You might want a mild flavor with a lot of proteolysis that's a deep blue color. Can pick that one.
If I buy some commercially, is it worth culturing at home?
IMHO, no. Unless you get a lot of satisfaction from being a mad scientist, it's much easier to buy commercial strains. Like for my stilton recipe, any mild strain of blue works.
Because I doubt I want to worry about maintaining O2 conditions, temp etc.
You can do it simply, like by opening the lid and shaking up the custom crouton cubes and letting oxygen in there. But IMHO, not the best approach, it can be inconsistent. And often not worth it unless you're doing things on a large scale.