There are a couple of ways to tie meat securely and tightly. Some applications require a quick tie (chain hitch) that will hold the roast together, other applications will require an anti-slip slip knot to ensure that you have a very tight product. You can find the chain hitch all over the internet so I won’t bother showing you the details here. This page was more inspired by my failed attempts at tying pancetta into a roll for hanging. I usually made a Venetian style pancetta which is not rolled and just cured flat. Of course I couldn’t go on with making flat pancetta and not knowing how to make a rolled pancetta. A tight knot is important because if any air is caught in the middle of the rolled pancetta, it will rot from the inside as it ages. I am not sure what the name of this knot is but if anyone knows please feel free to contact me and let me know. This knot was taught to me by a butcher (Eric Finley, Chop) based out of Portland.
If done properly this knot will hold very tightly and should not slip. You should be able to get one finger at the most underneath the string, if you can get more it is not tight enough.