Washed-rind cheese

This encourages the growth of certain bacteria on their surface which give them distinctive flavors.

Conversely, the term "washed rind" is sometimes reserved only for the hard ones.

Washed-rind cheeses are periodically cured in a solution of saltwater brine or mold-bearing agents that may include beer, wine, brandy and spices, making their surfaces amenable to a class of bacteria (Brevibacterium linens, the reddish-orange smear bacteria) that impart pungent odors and distinctive flavors and produce a firm, flavorful rind around the cheese.

[1] Washed-rind cheeses can be soft (Limburger), semi-hard, or hard (Appenzeller).

The same bacteria can also have some effect on cheeses that are simply ripened in humid conditions, like Camembert.