Blues are cheeses you deliberately grow mold inside. With Penicillium roqueforti and a needle to let air in, a home maker can produce a genuinely great blue — provided you keep its spores from invading every other cheese you own.
⚠ Read before you start
Home cheesemaking can cause serious illness when done carelessly — Listeria, E. coli, Salmonella, and (rarely) botulism are real risks, especially with raw milk, soft cheeses, and improper aging. The pages in this section are educational, not professional food-safety advice. Read the cheesemaking safety guide first, follow current local food regulations, and make at your own risk.
⚠ Isolate your blues
P. roqueforti spores travel through the air and will colonize your other cheeses — age blues in a separate box or fridge, and handle them last. Blue cheese is also higher in histamine and tyramine; people sensitive to those, and the usual higher-risk groups, should be cautious. As always, use pasteurized milk for home blues and discard anything with off (not blue) contaminating mold or a putrid smell.
Difficulty
Intermediate+
Active time
~3 hr + drain
Aging
2–4 months
Yield
1 wheel
Risk level
Med–high
A blue is built loose and open on purpose. You add P. roqueforti to the milk, make a curd that you don't press hard, and let the wheel drain so its interior stays riddled with tiny air pockets. After salting and a couple weeks of rind development, you pierce the wheel with a needle or skewer — the channels let oxygen reach the dormant mold, which blooms blue-green along them. The cheese ripens fast and ferociously. The two hard parts are keeping the paste open enough to vein, and keeping the mold contained to this one cheese.
Method
Ripen with the mold
Warm 1 gallon pasteurized whole milk to 88°F (31°C). Add mesophilic culture and a dose of P. roqueforti; ripen ~60–90 minutes. Add calcium chloride and rennet.
Set & cut
Rest to a clean break, then cut to ~½-inch cubes. Let rest; stir gently and infrequently — you want the curds to firm a little but stay loose, not knit together.
Drain loosely
Ladle curd into a tall form set on a mat. Do not press. Let it drain under its own weight, flipping the form periodically over ~24 hours, so the wheel stays open and a touch crumbly.
Salt
Unmold and dry-salt all surfaces over a day or two (rub, rest, repeat). Salt is heavier here — it tempers the aggressive mold.
Rind & pierce
Age at 50–55°F (10–13°C), ~90–95% humidity. After ~1–2 weeks, pierce the wheel top-to-bottom in many places with a sanitized skewer. Within days, blue veins develop along the channels.
Ripen & wrap
Continue aging 2–4 months, scraping back any excess surface mold. Wrap in foil for the final stretch to slow the rind and concentrate the interior. Taste from ~8–10 weeks.
Containment is the whole game
Treat blue spores like glitter: they get everywhere. A dedicated ripening box (or a separate small fridge), handled after — never before — your other cheeses, plus washing hands and tools afterward, keeps your bloomy and hard wheels from turning unintentionally blue.