Choosing the String
When you want to tie a pork roast, purchase cotton butcher's twine, also known as kitchen twine or cooking twine. You can usually find it in various lengths and thicknesses, but it is the material that should interest you most. Butcher's twine can stand up to the high heat of your oven without burning, which can't be said about regular string. Use a new section of butcher's twine with each new roast. If you are planning to sear the outside of the pork roast before roasting it, dip the twine in water before you tie the roast so it doesn't scorch or dry out.
Reasons for Tying
It's not always necessary to tie up a pork roast to keep it together, but there are a handful of reasons why you might want to tie it. A roast looks professional and neat when it is tied, making it an attractive dish for a dinner party. Tying the roast will help keep any stuffing inside if you have stuffed it, and tied roasts are usually easier to carve. Tying also helps it cook evenly, which means the roast will be able to reach the recommended 145 degree Fahrenheit internal temperature all the way through.
Types of Roast
Some people might picture a specific cut of meat when they hear the term "pork roast" because of their past experiences. However, several cuts fall into the category of a pork roast and can be tied with butcher's twine. A pork loin roast, pork shoulder and a pork rib roast are all candidates. Sometimes, two sides of a pork loin are tied together with the twine and then roasted in the oven as one whole roast. A pork tenderloin is usually small enough that tying isn't necessary.
There are many ways to tie a pork roast, depending on your experience, skill level and the cut of pork being used. One basic technique is to cut a piece of string that is several feet long and loop it around one end of the roast, tying a simple knot, so the entire length of string is still free. Then, pull the long end of string about an inch toward the other end, hold it down with your finger and loop it all the way around again. Thread it under the looped string and pull it another inch toward the far end of the roast. Continue this pattern until you reach the other end. It should have a circle of string running around the roast every inch or so, with a straight line of twine along the top.