The greatest clam chowders usually come from a dockside restaurant, but if you don’t live in a Lifetime movie, you might not have access to one. The next best thing on a rainy day is the canned stuff.

Clam chowder is a comforting classic, whether it’s New England–style with cream or Manhattan–style with tomatoes. But not all clam chowders are created equal. Many canned or restaurant versions pack ...