Combine the pork, fat and crushed ice in a bowl and then, working quickly, use a meat grinder to grind the mixture through a 1/4 inch (6mm) die. Preferably grind the meat mixture into a bowl set atop an ice bath to keep the meat cold. Grind half of the ground mixture a second time. Note: It is imperative that the meat be at a constant cold temperature so that the fat doesn't get too soft. You should be able to see clear definition between the lean meat the specks of fat in the ground mixture.Chill the meat in the refrigerator while you assemble the spice mixture.
In a small bowl combine all the spices.Remove the ground meat from the fridge and place it on the stand mixer fitted with a paddle attachment. Add the spice mix and dry milk powder.Mix the meat mixture with the paddle for 3-4 minutes until threads begin to appear in the meat: If you take a clump of meat and pull it apart with your fingers you will see tiny threads pulling apart. When you see this your meat is ready. *If the meat mixture is too dry and stiff, add a little ice water. You want a soft/smooth mixture that will easily go into the casings.*This is also the time to taste your sausage mixture so you can adjust the seasonings if needed. To do this, take a bit of the meat mixture, fry it up in a pan, taste it and adjust the seasonings if needed.Place the meat mixture back in the refrigerator while you prepare the casings.
Thread your sausage stuffer with the prepared hog casings, fill the sausage stuffer with the meat mixture, and stuff the casings being careful to avoid air gaps while also being careful to not over-stuff the casings.Twist the sausages into links. Use a sausage pricker to prick any air bubbles out of the links.For best results chill the sausages overnight.
To prepare the bratwursts, gently poach them in lightly salted water and then fry or grill them. Once poached they will keep in the fridge, tightly wrapped, for up to a week. You can either freeze the Bratwursts raw prior to poaching (then thaw, poach, fry/grill) or freeze them once they're poached.
This yields roughly 10 bratwursts depending on the size and diameter.