A humboldt fog is a lactic-coagulated curd, like chevre, with the ash, and coated in a p candidum mold. Make a standard chevre, with the ash/salt in the middle, sprinkle with ash, salt (2% total), and spray with candidum or add candidum to the milk. Age on the cool side -- there's just a thin liquefied layer on the outside of humboldt fog. It's a complicated cheese because it is remarkably well drained, even for a huge 5-pound wheel of it. I suspect one of the tricks is to stir the curd or turn the edges of it to expose the center, so that the wet curd is exposed to the outside and drains faster.