When travel partners and chefs Anthony Bourdain and Eric Ripert were in Lima, Peru, for CNN’s "Parts Unknown," they discussed what makes ceviche a great dish. They said all of the ingredients — fish, herbs, vegetables, and spices — must be of the freshest quality, and they also agreed that the cut of the fish is just as vital.

Bourdain and Ripert said that the pieces of fish in ceviche need to be on the larger and thicker side, with more surface area to stand up to the flavors of the spices and the acidity of the citrus. The process of "cooking" the fish in ceviche with acid is called denaturation, and it works better with thicker slices rather than smaller-diced pieces.

Denaturation changes the chemical composition of the fish, imparting flavor while turning the fish opaque, as if cooked, even though it's still technically raw. Thick pieces of fish, at least ¼ inch thick or more, react better to the citrus without losing too much of their pristine fish flavor, while still being bite-sized and easy to eat.