Moldy. Pu 'er tea cake is pressed tea. There is a gap in the middle when pressing, but the edge is pressed tightly. Because the tea leaves are wet and can't be discharged, there will be something white and gray in the middle. It's okay to drink this kind of tea next to you, because this situation is quite special, because the middle is like a semi-vacuum state, which won't have any effect on you, but you don't want to drink the tea with white ash within one finger, which is not good for your health. It doesn't matter if you don't want to give up.