Did you know Cheddar cheese is orange because of food colouring? I just found out. It's not like it's toxic or anything, but still it was a shock. Somehow I'd always assumed the orangeyness was just a byproduct of some traditional cheese making process. I checked my package of cheese and sure enough, it listed "colour." So why is Cheddar coloured orange? I felt like a rat in a maze trying to find out.
Orange You Glad I Asked
First of all, I found out that in fact, not all Cheddar is orange, including most of the stuff in England, although other cheeses, like Cheshire, are. In the States, Cheddar from Wisconsin is mostly orange, whereas Cheddar from New England is usually white, as are Cheddars from Ontario and Quebec. I went to a hard core cheese store which sold only white Cheddar. Sometimes people think they can taste differences, but these are more likely the result of differences in aging or in pasteurized versus raw milk. The cheese guy I spoke to said he just preferred unadulterated cheeses on principle.
Colour My World
Since at least the 1800s, in those Cheddars that are orange, the colour comes from annatto or roucou, the red seeds of the achiote tree (Bixa orellana) native to central and south America. The Aztecs used it as body paint. The seeds contain bixen and norbixen, which are caretenoids and antioxidants. But that doesn't seem to explain why they were added to cheese in the first place.
Cheddar cheese began in a place called Cheddar, Somerset County, England. Cheesemaking in the area goes back to 1170 AD and something distinguished as Cheddar cheese to the 1500s. Cheddaring is now the term for a method of dealing with the curds, though not only in Cheddar.
Back when cows actually ate grass, they produced a more yellowy milk in spring and summer because of the beta carotenes in the grass. Over the winter, they ate hay, which is dried grass. It has lost the beta carotenes, so the milk is paler.
Perception is Everything
People saw the yellower cheese as being better, so cheese makers added colour to make the cheese look darker all year and fetch a higher price. In another version of this, cheese makers outside of Cheddar added colour to make their cheese more like the cheese from the well-fed cows of Cheddar.
Then, in a cheese maker's arms race, more colour was considered better until it ended up orange. Orange cheese became a purple cow, a way to be remarkable and distinct. This may explain the orange in the Wisconsin cheese and the mass marketing of orange processed cheese that has led to my perception that cheddar is orange at all.