Wallie
I'm sure I'm not the best person to explain all this but here goes anyway:
Saltpetre is Potassium Nitrate (KnO3) E251
Sodium Nitrate is sometimes called Chile Saltpetre and is NaNO3 E252
Cure #1 (also Prague Powder #1 and Instacure) is Sodium Nitrite NaNO2 E250 mixed with salt. Normally it is 6.25% Nitrite but the one Franco sells on the main site is 5.88% Sodium Nitrite. For the purpose of this, I will assume you use Franco's at 5.88%.
Saltpetre is 100% Potassium Nitrate so does not add salt.
Cure #1 being only 5.88% Sodium Nitrite, the rest salt, adds 94.12% of its weight in salt. So 100g of cure #1 has 5.88g Sodium Nitrite, 94.12g Salt.
To calculate the Parts Per Million (PPM) Nitrite that is going to be in a dry cured product I use the formula from the
US Meat Inspectors' handbook:
weight nitrite � % cure mix applied � 1,000,000=ppm
weight cure mix
Let's take an example for cured meat with the following cure:
Salt 16gm
Sugar 9gm
Cure#1 2.6gm
TOTAL WEIGHT OF CURE 27.6gm
CURE USE PER KG 30gm
The weight of Nitrite will be 2.6g x 5.88% = 0.15288g
The % cure mix applied is (30 / 1000) x 100 = 3% (The US method expresses this as 0.03 in the calculation which may not make sense but it's how it works - for an explanation see
here)
The weight of the cure mix is 27.6gm
So the calculation is:
0.15288 x 0.03 x 1,000,000 = 166.17 PPM
27.6
Pocket size electronic scales are ideal for measuring the small amounts of cure and, in my view are essential when using saltpetre.
I hope this helps.
Phil