by wheels » Mon Apr 13, 2009 8:02 pm
OK Wallie - I'll have a bash at it!
Nitrite and Nitrate
The formula for calculating PPM (Parts Per Million) nitrite in an injected brine cure (page 19 of the handbook - which is page 24 of the .pdf file) is:
lb nitrite � % pump � 1,000,000 = ppm
lb pickle
This works for gms as well as lb's (as long as you stick to one type of measure for weight).
We'll take this brine as an example:
Water 1000 gm
Salt 110 gm
Sugar 124 gm
Nitrite (Cure #1) 32 gm
Total 1266 gm
Pumped/injected at 10% of the meat's weight.
The formula as above is for use with pure nitrite; our's from franco is only 5.88% pure, so we need to calculate how much pure nitrite is in the 32gm cure #1 we are using:
32 x 5.88% = 1.8816gm nitrite
For some reason the handbook expresses the % pump (inject) as a hundredth of its value so 10% pump becomes 0.1 (10/100)
So our calculation is:
1.8816 (the nitrite) x 0.1 (the pump) x 1000,000
1266 (the total brine)
or
(1.8816 x 0.1 x 1000,000)/1266 = 148.6256 PPM (rounded to 149 PPM). PPM is the same as mg/kg.
The nitrate can be calculated in the same way.
Salt
To calculate the salt % in the ham first we work out how much salt is in the brine:
We have 110gm salt, plus the salt in the cure #1 which is 32gm less the 5.88% nitrite, that is 100% - 5.88% of 32gm cure #1:
100% - 5.88% (% nitrite in cure 1) = 94.12% (% salt in cure #1)
32gm (cure #1) x 94.12% = 30.1184 gm (salt in cure #1)
30.1184gm (salt in cure #1) + 110gm (pure salt added) = 140.1184 gm salt
We then calculate how much brine is in the meat - this is the weight of the meat (we'll assume 1200gm of meat in this case) x the % pump (10% in this case)
1200gm x 10% = 120 gm
Now we want to know what percent the salt is, of the total brine:
We divide the total salt (140.1184gm) by total brine (1266gm) and then multiply this figure by 100.
140.1184gm/1266gm x 100 = 11.0678%
The amount of salt in the meat is this % of the brine injected (120gm):
120gm x 11.068% = 13.2816 gm
The salt % in the product is this amount as a percentage % of the meat weight:
13.2816gm (salt in product) x100 =1.1068%
1200gm (meat weight)
I hope this helps
Phil