Equipment:
'88 Vintage Fire Magic gasser with over 4000 cooks to its credit
Large Big Green Egg
18 Inch Weber Kettle (Rescued from neighbor's trash)
Rotisserie for 18 inch kettle
Dyna Glo propane smoker
Pit Barrel Cooker
Smokey Joe with mini WSM mod
Garcima paella burner
Anova Sous Vide
Slaiya Sous Vide (gift)
LEM grinder, sausage stuffer and meat slicer (all gifts)
Spend a few extra bucks and get a 5 pound vertical stuffer that has steel gears. The issue with the horn stuffer is "tinned" meaning eventually it will rust. The little one that clamps with a single clamp may be OK, but we have to use two real "C" clamps to keep ours from walking around when we stuff. (It's intended to be bolted down to a work table of some kind, but for occasional use that's impractical).
Casings that are "tough" has a boat load of potential causes including crappy casings, but the LEM home packs that you linked has worked for us through the years. A common problem is drying out during smoking particularly at high temperature. I don't know what you are using for a smoker, but if possible add something that will increase humidity like a tray of water. Stuff as tightly as you can, this eliminates air pockets under the casing that exacerbates drying. Finally, we ignore the instruction on the package that says soak in water for an hour or whatever. We soak for at least 6 hours and usually overnight with several water changes and flushes. This completely re-hydrates the casing and flushes as much salt out as possible.
Dryness is probably caused by lack of binding of moisture and fat with the meat. The most straight-forward fix is to ensure thorough mixing of very cold mince. The mince should be very sticky when sufficiently mixed. As pointed out above, non-fat dry milk powder aids in moisture retention, BUT the stuff you get at the grocery store doesn't do much. You have to get non-fat dry milk powder that is manufactured using a high heat process. You can get it from sausage suppliers and/or bakery suppliers.
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