You could use pre-ground meat, but then you don’t know what is in it. It’s best to grind it yourself using good quality meat: 75% meat and 25% fat.
There are number of grinders available, from stand alone electric grinders to small manual grinders that attach to the worktop. I have tried a number, and they are all good for the job. The manual ones just burn of a few calories while you’re using them, which may not be a bad thing.
Once you’ve got your grinder all set up, make sure the meat is cold, some use almost frozen, this makes sure that the meat and fat doesn’t turn to mush as your grinding. Chop you meat and fat into 1 inch cubes, mix it all together and pass it through the grinder using a coarse. Now mix in all the other ingredients for the sausage.
Water is important as you want the mix to get to a sort of paste looking texture. The water helps the meat in the sausage retain the fat making it juicer.
Once the meat is all ready, add the sausage stuffing attachment to the blender; make sure you remove the blade from the blender. Pull on the hog casing over the sausage attachment and tie off the end. Slowly pass the meat through the blender. Keep going until all of the meat has been used. Now starting at the end, twist the casing into sausage shapes. Twist each sausage in the opposite direction.