According to regulations, the minimum aging period is 75 days, although for connoisseurs the optimal storage time is around 3 months (during which the characteristic mould will develop at its best). During this period, the cheeses are pierced by hand on the faces and on both sides with a copper needle. This procedure allows the air to enter the cheese and create mould where the two pastes have not amalgamated. Because ‘the evening curd’ and the ‘morning curd’ have different textures and levels of acidification, they do not amalgamate well with each other, leaving space that is filled with air, after piercing. It is precisely here that the blue veins begin to develop naturally.