Hot packing is cooking it before placing it in the jar. It can help shrink the meat so you get more in the jar. I think you have to add water/stock as much of it cooks out of the meat when done ahead of time. It is easier IMO to do the cold pack. I think the recipe I used called for about 1.5 pounds per quart jar.
FL Native, it does not effect the taste, it is simply like slow cooking as far as what it does. You can also pressure can tuna, salmon, and other seafood as well.