Italian style cheeses such as Provolone, Scamorza, Mozzarella and Caciocavallo fall into a category of cheeses known as 'pasta filata' or 'stretched dough' cheeses. These cheeses undergo a specific and fascinating step whereby a finished ripened curd gets melted with hot salty water then stretched into various shapes. The key to successful 'pasta filata' stretching is making sure the curd is properly acidified and that the stretching water is warm enough.
Step 1: Chop Ripened Curd Into Strips
You might get the curd needed for this Instructable by following a recipe such as this one ("How to Make Successful Quick Mozzarella Curds"). Or you might decide to make a more complex mozzarella curd recipe made through culturing milk with bacteria. Or you might purchase pre-made mozzarella curd from a local manufacturer (such as Bel Fiore in Berkeley, CA). Once you've gotten some curd, proceed with warming it up to room temperature then chopping it into slice or bites (roughly the size and shape of vanilla wafers or slender carrots).
Step 2: Cover With Hot, Salty Water
Take a handful of curd 'chips' (about 1/2 to 1 cup worth) and place them in a large mixing bowl. Next, cover chips with hot (155 to 185 degrees Farenheit) water to which you've added ~2 teaspoons kosher salt per 1 cup water. The water should be 'salty like the sea'. Also, confirm that the water is hot enough by using a thermometer.
After covering the chips with water, wait for one minute. After, pull on one of the chips and see if it stretches easily as shown in the photo. If it does, you are ready to proceed. If it doesn't, wait another minute (and possibly add more / or hotter water to the bowl).
Step 3: Flatten and Stretch Curds
Working fairly quickly, start to flatten and stretch the curds. Some people do this by removing curds ('chips') one at a time from the water and flattening them. Others do more of a 'flattening and stirring' motion while the curds are still in the water. What you are looking for is the curds to turn from chunky bits into flattened, silky ribbons.
NOTE: It is possible to overwork the curds. Try and stop stretching as soon as you see the majority of the melted curds have turned stringy and shiny and then immediately form them into a final shape. Overworking will cause your final cheese to be tough and meaty looking (not shiny).
Step 4: Gather Chips Into One Mass
Once (or just before) all the melted cheese chips are completely shiny and stretched, start to gather them into one big mass of cheese.
Step 5: To Make a Ball
Squeeze off any sized portion of the main cheese mass. Smaller balls are called 'ciliegine'. Larger ones are called 'ovaline' or 'bocconcini'. The important part of this motion is that you quickly and thoroughly squeeze / rip the cheese off / away from the main mass using your pointer and thumb. This motion helps seal up a finished ball. When finished, immediately drop the lassoed purse into cold water.
Step 6: To Make a Scamorza
If, instead of a ball shape, you'd like a 'Scamorza' or pouch shape, you can stop at this point shown in the picture--before completely tearing the cheese ball away from the extra cheese mass. This preserves a little gathering of cheese which looks like the top of a coin purse. Use a small piece of cord or a rubber band to lasso the neck of the purse then immediately drop the lassoed purse into cold water.
Step 7: Hold in Cold Water
After shaping, keep the cheese in cold water for approximately 10 minutes--or until it feel quite firm and no longer 'stretchable'.
Step 8: Dry, Smoke or Eat
After the pause in cold water, you can eat the cheese. Or for a saltier, more aged cheese, you can place the cheese in a heavy brine for 10 minutes (more time if the cheese shapes are larger). After brining, dry the cheeses and allow them to age in a cheese cave setting or move them to a smoker for even more flavor.
Step 9: Here's a Video of Me Stretching Curd Into a Provolone 'pin Cushion'.