When it comes to one-pound boxes of salted and unsalted butter sticks, salted sticks usually come in a blue wrappers and unsalted in red wrappers. Many brands match those colors on their box designs, which seems intuitive and sensible (see first photo), while other brands do the opposite, pairing red box graphics with blue wrappers and vice-versa, which seems confusing and counterintuitive (second photo).

How did blue and red become the default wrapper colors for salted and unsalted butter? Why would a brand choose not to match the box colors to the wrapper colors? And why are there a few brands that use a completely different color system?

I recently undertook an epic investigation into those questions. It features dozens of butter packaging photos, several painstakingly assembled tables/charts, and insight from industry experts. An obsessive’s delight!