Red and gray corned beef are created differently based on the curing process and the amount of salt used, as gray corned beef is made with brine and natural salt, and red corned beef is made with sodium nitrate. The gray type is known as Boston Irish style corned beef, and the red type is known as New York style corned beef.
Gray corned beef is typically found in New England, and it is one of the most common meats eaten on Irish holidays, such as St. Patrick’s Day. Red corned beef is one of the most commonly found corned beef products, and it is available all over the world.
When red corned beef is cured with sodium nitrate, the chemicals keep the meat's cells from oxidizing, resulting in the red color. Sometimes different spices are also added to the mix, resulting in a variety of flavors that may contribute to the redness. Gray corned beef retains its color from the oxidation process, and most traditional gray corned beef recipes use salted brine exclusively without the addition of other spices.
In addition to differences in color, gray corned beef is sweeter and softer than red corned beef, though red corned beef has more variations in recipes and flavors.