I'll add a 3rd opinion that 1/8th cup sound like a huge amount.
I use Butcher & Packer #414 "special binder" and AmesPhos and neither of them are anywhere near that high a ratio. What quantity of meat was that 1/8th cup in a cup of water supposed to mix with? B&P 414 is 2 ounces (by weight) to 25 pounds of ground meat. That works out to just 11.34 grams in 5 pounds of meat. AmesPhos is 0.3 to 0.5% of the total weight of meat, so for 5 pounds that would be 6.8 to 11.34 grams for the same 5 pounds of meat (5 pounds of meat is 2268 grams x 0.003 for 0.3% etc...).
Oh wait, I think I see what's going on. I looked at the Moisture Magic product site and they have a couple of instructions.
The 1/8th cup to 1 cup of water is for INJECTION. For mixing with meat (as in sausage, sticks, etc....) it is listed as 1 ounce to 12.5 pounds which is the same as the B&P 414 at 2 ounces to 25 pounds of ground meat. So 2.27 grams per pound or 11.34 grams for 5 pounds of GROUND MEAT would be spot on.
How are you using the phosphate in your recipe? Injection, brine, or mix with ground meat as it makes a difference.
One other comment, the B&P 414 is also a little difficult to dissolve in water IMO. You need to crush any lumps to dust before adding to water. I've had the best results in ground meat by crushing up the B&P as much as a can with the back of a spoon and then adding it to my overall measured spices and mixing it in. Then add all the spices to the wet (water, beer, etc...) to make a slurry to add to my ground meat. No problems with clumpy messes that way for me.
That 1/8th cup for a cup of water in an injection still sounds off to me. They list 1 cup to a 1/2 gallon of water for a brine. 1/2 gallon is 7.9 cups so the ratio they list for a brine is 1:7.9 and the ratio of 1/8th cup to a cup is 1:8 which is virtually the same. Devil is in the details as it "sounded" like a lot more when I first read it, but I guess it's the same as their brine amount.
I've not injected phosphates or used them in a brine. I just use them in ground meats and I swear by them and the results they give. You don't need NFDM or soy binder if you use phosphates. And phosphates are a natural compound so it's not franken-food.
Also you might want to look at B&P 414 as it is about 1/4 the price of the Moisture Magic price I saw on
Amazon.