Both? Well, occasionally both.

OK, your roast has been tied up to hold it in place and give it a nice, even shape. It is not subjected to anywhere near the same pressures in the grocer's refrigerator case as it is in the heat of the oven, so you absolutely keep it intact during cooking. Otherwise the meat will twist and unroll, and the poor butcher will wonder why he took the trouble to tie it in the first place.

It can seem a little messy to remove the strings tying your roast or string mesh when the meat has been cooked, but that's a price you pay for having an evenly cooked, pretty roast that you are proud to serve. We'll take the time here to plug our favorite kitchen shears, which make the job much easier than trying to untie the knots or bite through them with your teeth.

It is possible, and occasionally called for in recipes, to put a delightful stuffing in your roast, particularly if you have a rolled piece of meat (such as a deboned leg of lamb) rather than a whole roast. If that is the case, you cut the strings first, unroll the meat, place or spread the stuffing in the middle, reroll the roast, and tie it up again. This holds the stuffing in place and, again, keeps the meat from twisting and cooking unevenly.

We have had some success removing a rolled pork roast from a modest hole in its string bag, stuffing it, stuffing it back into its string bag, repairing the hole, and reusing the original strings. If you can't manage that, or if the roast has just been tied simply, you'll have to resort to butcher's twine or some of the high-tech silicone products that are now available to help you get that roast back into shape and lock it in place.