Cheddar cheese is a combination of cheddar cheese and monterey jack cheese. Cheddar jack cheese can be made by marbling the curd from both cheeses in a mold, or by combining and packaging shredded forms of the two cheeses.
Cheddar cheese is made with a process called cheddaring. After the curd is separated from the watery whey, it is formed into large blocks of cheese that are stacked flipped many times to release more whey and create a denser curd. At the end of the process, the slabs are milled to create smaller curds which are pressed into a mold where the cheese drains and is left to age. The aging process is what creates different types of cheddar cheese. Mild cheddars are aged 3 to 6 months. Sharp cheddar cheese is aged 9 to 12 months, and extra sharp cheddar cheese is aged up to two years or longer.