What are the fundamental differences between types of bacon?!

Shoulder bacon is still fatty, but instead of strips of fat and meat like classic breakfast belly bacon, it has large chunks of leaner meat. As a result, it is not suited to being sliced thin and fried like belly bacon. The large chunks get too dry in the frying pan and due to curling they cook unevenly. I like to use shoulder bacon in half-an-egg sized cubes to season braises and stews with the indispensable triumvirate of rich cooking: smoke, fatty pork and salt.

Pancetta, while from the belly, should be prepared differently than belly bacon. In addition to not being smoked, it should also have been aged for a few months. This mellows the salt flavor and hardens the texture of the meat and the fat. Sliced and fried like belly bacon, it would probably be a little too salty. It reaches its full potential when traditionally prepared: cut into narrow ribbons a little smaller than paperclips then set on low heat in a well-seasoned skillet. The cured fat will slowly render, offering pan-juices that are the beginning of just about anything that will taste better as a result of bathing in pancetta juices: a sauce, fried egg, fried brussels, kale and most traditionally pasta carbonara.

Guanciale from the jowl should be used the same way. I like my pancetta to be strong so I cure it with lots of garlic and pepper. My guanciale is more mild, cured with lots of sugar and even some cinnamon, more suited to cream sauces. It is also wonderful sliced paper thin and eaten raw.

Unfortunately, these traditional preparations only work with traditionally cured pork. Most the pancetta you find today just browns and sticks to the bottom of the pan because it is too young and you tend to lose the subtle pork butter flavors of guanciale in an overly tangy sourness. The stuff you make at home will be a completely different product, vastly superior.

What differs is where the bacon is cut from on the pig and how it is brined and smoked.