Wiki and handbook say it needs to be ripened in a cellar with "at least one block open to the outside", but that's quite paradoxical isn't it? A cellar by definition is an enclosed space.
My cellar is underground, and no matter how long of a corridor of blocks I build to the outside my shelves don't display as suitable for ripening. I tried if an open hatch or an open door counted as an "open block" since they retained the room's cellar status, and I even tried chiseling a small hole instead of removing a full block to access the corridor. All resulted in cheddar.
I found a russian tutorial/article from last June that seems to conclude (had to use a translator) that blue cheese had to essentially be open-air aged in a low sunlight place, in a climate cold enough where shelves placed in caves had a natural modifier of x0.5 or lower. I'm in the middle of summer in a warm climate (35c+ midday) and I don't think I can venture deep enough underground to find ambient temperatures that are suitable, if they exist. I'll basically need to find a translocator to some northern area to pursue this further, or try and check my cave temps in winter and time my ewes accordingly
Have any players in warmer climates managed to actually make blue cheese? If yes I would love to know your setup!