A day before you'll serve the pâté, mix all the meats together with bay leaves, thyme sprigs, tarragon, pink salt, and beer. Cover and refrigerate overnight. This is also a good time to place any metal parts from your meat grinder, and a bowl as well, in the freezer to thoroughly chill.
Remove the bay leaves and sprigs of thyme, setting them aside for later use. Set up the meat grinder and grind the mixture of meat into the chilled bowl, keeping it as cold as possible throughout. (If you don't have a meat grinder, you can also pulse the meat, in batches, in a food processor.) Season the mixture with salt and pepper.
To check the seasoning, heat some canola oil in a small sauté pan and fry a bite-size chunk of the mixture until cooked through. Adjust with more salt as desired.
Preheat the oven to 325 degrees. Place the bay leaves and sprigs of thyme in the bottom of a terrine mold or a standard loaf pan. Line the mold with the ham, over the herbs, leaving enough ham hanging over the edges to cover the top of the pâté. Fill with the meat mixture, then bang the terrine mold on a table to remove any air. Fold the ham over to cover the pâté. Put the terrine cover on, or wrap with foil.
Bring about 2 quarts of water to a boil. Pour the hot water into a deep casserole pan large enough to hold the terrine mold. Put the mold in; the water should come about 2 inches up the side.
Bake for 60 minutes, or until a meat thermometer poked into the middle registers 160 degrees. Remove from the oven, and place the terrine mold on a towel or other safe surface to cool to room temperature.