Blue cheese varies in consistency from semi-soft to very soft, in
color from pale yellow to white, and in flavor from mild to sharp. It
can be made from sheep's milk, cow's milk, or goat's milk. Constant,
however, are the blue veins that weave through the cheese and
its unmistakable pungency.
It begins its life much like any soft white cheese, but instead of
being made from curd pressed firmly into a mold, it is only gently
shaped. The resultant cheese is riddled with nooks, crannies and
cracks, which often gives it a crumbly texture. These cracks are
infected with Penicillium roqueforti or Penicillium glaucom, each of which produces blue or greenish-blue spores. Using needles or
hollow rods, the cheese is aerated to encourage the fungus to
sporulate.
While some blue cheeses are pressed gently into their molds, enough
to squeeze out whey but not enough to compress the cheese, some blue
cheeses aren't pressed at all. Instead, they sit in their molds for
weeks as the whey drips out of them. Eventually, the molds can be removed
without the cheeses falling apart, at which point they can join their
pressed brethren in being salted, aerated, and infected.
This category of cheese is sometimes misrepresented as "bleu cheese," particularly by people who make cheap salad dressing in the USA.
For English-speakers, the correct term is blue cheese, b-l-u-e cheese. Using the word "bleu" to describe a cheese is appropriate for people who are speaking French or for anyone referring directly to an
actual French blue cheese in which that is part of its name. In all
other cases, 'bleu' is Francification encouraged by people whose cheese
is neither French nor worth putting in one's mouth. Decent non-French
blue cheeses, like Maytag, Stilton, Saga Blue, Gorgonzola,
Shropshire Blue, Picon or Blue Castello require no such
pretension. Actual cheese names should be left in their language of
origin, and those names are chosen by the cheesemaker; cheese
categories don't belong to any one particular country, culture, or
language and therefore should be in the speaker's language. Therefore,
the type of cheese is "blue cheese" or "fromage bleu", and
specific cheeses are "Bleu de Bresse" (from France) or "Blue
Cheshire" (from England); "bleu cheese" is nonsense. | 
