Here's the nutritional breakdown it's based on 100gm sausage so that what I'll base my figures on also.
Your ingredients when cleared out are:
Ingredients
Pork (80%), Pork Fat, Water, Wheat Flour, Salt, phosphates, Spices, Sodium Sulphite, Monosodium Glutamate, Sodium Ascorbate, Spice Extracts, Maltodextrin
It's in Natural Sheep Casing
Pork fat has to be listed separately when VL of the meat is less than 80% i.e. visible fat in the meat exceeds 20%. That's just visible fat. There will be fat hidden in the meat.
We are told that it's 80% pork plus some pork fat. In 100gm sausage the 80% pork is 80gm. If it's 20% visible fat that's 16gm fat. To this we add the hidden fat The nutritional info tells use there's 28gm fat in 100gm sausage. My QUID declaration calculator (QUID is the EU standard on which the description is based) tells me that if I use 70% VL pork I will need 89gm to give an 80% pork declaration. I'm guessing that the fat is therefore around 8 or 9gm. It must be more than 6gm otherwise the whole lot doesn't fit with the figures we know for sure like the salt.
We know that the salt tests at 1.9gm. That's the added salt plus the salt in the meat. We know from some tests NCPaul did that the natural salt in the meat will be around 0.17%. That's small enough to be negligible but we'll reduce the salt to 1.8gm to allow for any salt in other things like the additives.
We know that the amounts of water and flour must be more than the salt at 1.9gm per 100gm and less than the fat at 8 - 9gm. Each of the other things must be less than the 1.9gm salt.
Ascorbate cannot exceed 500mg/kg IIRC that's 0.05gm.
Phosphate is used at 0.8% - 8gm per kg according to the stuff for sale at the site shop that's 0.8gm
Sulphite preservative is used at 0.8gm per kg = 0.08gm
Monosodium Glutamate must be between 0.08 and 0.05 say 0.06gm
Spice extracts must be less than 0.05 as must Maltodextrin let's say 0.07gm between them.
This leaves the spices, flour and water. Each must be more than the one below it and less than the one above.
We know the spices must be less than 0.8gm and more than 0.08gm. I don't know whether it's spicy or not but around 0.5gm – 0.7gm seems about right. I'm going with the lower amount.
We're left with about 9gm for flour and water. I'm surprised it uses just flour and not rusk. That's unusual. I think you'll have to play with them to get the texture you want. The nutritional details show 2.9gm carbs but 2.3gm of this being sugars. This is confusing as flour is 78% carbs but only 1.5% sugars according to my wholesalers details on the flour I buy. This leads me to believe that the majority of the missing 9gms or so is made up of the water but in that case where the dickens are the carbs and sugar from? The spices and maltodextrin aren't high enough to give those levels.
I'm going with 2 gm of flour and the rest water for no other reason than it pleases me and is roughly a teaspoon. It can't be more than just over 4gm at a maximum otherwise the water wouldn't be more than it.
The 100gm sausage now looks like this:
For a 1kg mix it's:
I was being pedantic showing 65.9 water. You just use 66gm obviously.
You're on your own with the spices I'm afraid. Commercial mixes often major on white pepper though. It's a pity Johnfb doesn't seem to be around. He was great at working out the spices in Irish sausages.
I hope this is of some help. You could probably drive a bus through my assumptions and someone with more knowledge of meat science, or science in general, could probably tell a lot more from the nutritional breakdown. It does, however, give you a starting point. Hopefully, others will add to it.
Phil