Ash, sometimes called activated charcoal, is a food grade charcoal used on some soft cheeses to neutralize the surface of the cheese and create a friendly environment for the growth of penicillium candidum and other ripening molds while inhibiting unwanted mold growth. The activation is due to ionizing, which results in the ash being purer and very fine. This gives it the ability to cover a larger surface area, which greatly increases its absorptiveness. Ash is always mixed with salt before applying to your cheeses. Use anywhere from a 1:5 to 1:8 charcoal to salt ratio, depending on how heavy an ash surface wanted on the cheese. Cheeses with ash are worth maturing for longer periods of time and are not hard to take care of. They will usually develop a blue-gray, mottled rind, condensed, nutty texture and a strong creamy flavor
Molds such as P. candidum will grow best at lower acid levels (higher pH) than is typical in a final fresh cheese such as many goat cheeses where the pH may be as low as 4.7-4.8. This ash neutralizes the surface acid and will prepare a sweeter surface, especially for goat cheese and other high acid lactic cheeses. The ash covered surface will usually allow the final mold surface to develop quicker and more completely. Also, this seems to increase the rate of surface protein evolution which is responsible for that nice translucent area under the rind.
Mix ash with salt for applying. Within a few days the black rinds become grey as the white molds grow through it. Within 8-10 days the entire rind should be white. If the mold growth is blue instead of white penicillium your cheese is too acidic. If the molds are grey and hairy, the cheese is not acidic enough and is retaining too much moisture as a result.
Keep in original container in a cool, dry place. Will last indefinitely.