Does anyone know if different types of prosciutto are saltier than others? And which is the least salty?
For my pallet, the Spanish hams are less salty than prosciutto. Try something like a serrano. Don't be afraid to ask to try these hams. Most places will let you taste first, and if they don't then you need to purchase your ham from some place else!
I've found Prosciutto di Parma to be less salty than most of the "supermarket" brands. When I lived in NJ, the local Italian deli's had decent prosciutto but, here in Virginia, it's not so easy to find. I've tried some supermarket brands like Boars Head in a pinch but find it impossible to eat in a sandwich. I don't have details regarding why the Parma tastes sweeter and I don't think its a brand exactly.
Look for San Danielle and Parma from Italy, or Serrano from Spain. Anything from a huge name from the US or Canada is mass produced, and speed is of the essence, as are profits, so I don't know exactly what they do but I suspect they inject salt or salty brine, or tumble it. It does not go through the long curing process that an artisinal ham from Europe does -- salted on the outside only, air dried in very controlled environments, and taking time -- sometimes as much as 14 months. Correct me if I am wrong, but I believe that any "proscuitto" from North America is simply inedible, while Parma is divine.
There's a farm in Iowa, La Quercia, that does a nice job with prosciutto. Unfortunately, it's just as expensive as San Daniele (19.99/lb here). WF was carrying them. Not quite as creamy/silky, but probably the best domestic I have with one exception.
Here in Pgh we've got a place called Parma Sausage. They cure their own. Their prosciutto is 13.99/lb and is excellent. But... part of the key is knowing where they're slicing from. The salt content is not perfectly evenly distributed as it tends to sink while the hams are curing. If I'm using for panini, I'll want it cut from the thick end. If for cooking, then the narrow end is preferable.
And Parma's pancetta is phenomenal. Wonderfully nutmeggy eaten cold (it's cured long enough so no need to cook).
You may want to try Speck if available. It is more lightly salted than Prosciutto. I find the taste more complex and interesting.
Like prosciutto and other hams, speck is made from the hind leg of the pig, but, unlike other prosciutti, speck is boned before curing. A leg of pork is deboned and divided into large sections called "baffe", and then cured in salt and various spice combination which may include garlic, bay leaves, juniper berries, nutmeg and other spices, and then rested for a period of several weeks. After this the smoking process begins.
Speck is cold-smoked slowly and intermittently for two or three hours a day for a period of roughly a week using woods such as beech at temperatures that never exceed 20°C (68°F). The speck is then matured for five months. If you can find it try it. It ROCKS!