There are several considerations to take into account when making sausage, type of sausage being made and the materials available (including types of casings, availability of cures/additives etc.)
If I'm hot smoking something like pepperettes, kielbasa or smokies, I will use collagen casings or hog casings depending upon availability
I've had some problems with sheep casings. For summer sausages and others with a diameter over 1 1/2 inches, I normally use fibrous casings due to availability.
The problem with fibrous is that the melted fat will not make it's way through the fibrous casings and will congeal between the finished sausage and the casing. Is that gross or what?
To combat this I use less fat in my mixture, 70% venison/30% pork. For the pork, I use either leg or butt (shoulder). I found that this way my hot smoked sausages end up with the drier texture I desire without the fat build up inside the casing. I remove the casings and wipe down the sausages with a clean paper towel before vacuum packing and that works great. I use the same mixture for any venison sausage where a dryer consistency is desired after hot smoking (ie. pepperettes)
For Kielbassa, I use 100% pork from either the leg or butt (I don't like it too fatty)
For frying or grilling sausages it's a different story. I you go on Len Poli's site many of those types of recipes call for extra fat to achieve 20% - 30% fat content. This is easier for those who make bacon. By now those of you who make their own bacon have come to realize the meat/fat ratio varies through the pork belly, so here's what I do.
I grade my bacon such that the bacon strips with the best meat/fat ratio are packaged as bacon strips. For the remainder, I separate the rind, excess fat and meat from the strips that don't pass quality control and the ends. the fat and rind each get packaged into 1/2 pound lots, vac packed and frozen. What's let get cut into bacon bits, packaged into 1/2 pound lots and thrown into the freezer for the wife to use for cooking and salads. That will score you some points ( and a few Caesar salads).
Now you have fat to add to your sausages salvaged from your bacon making efforts. Take pure bear, venison or moose with the fat removed and now you can accurately up your fat content. For 20% fat content (which I use) add 1 lb. bacon fat to 4lbs. game meat. To properly mix, I grind it 3 times 3/8">1/4">1/8" adding the frozen fat to the first grind with the meat. Each successive grinding mixes the meat further until the last grind when the final product attains a uniform colour.
For breakfast sausages or hot Italian Sausages, I will add 1/2 lb bacon fat to 4.5 lbs. of pork. To ensure sufficient moisture after cooking, I have started experimenting with soya protein and sausage phosphates as recommended by Len Poli
Here's where you can get them;
http://www.dnrsausagesupplies.ca/index.php
These guys are located in western Canada and I have used them.
I hope this helps
Roe+
There are several considerations to take into account when making sausage, type of sausage being made and the materials available (including types of casings, availability of cures/additives etc.)