How to Apply Cures
Well, there are two approaches:
 Like an amateur  collecting hundreds of recipes and relying blindly on each of them. You lose a recipe and you don’t know what to do. And how do you know they contain the right amount of cure?
 Like a professional  taking matters in your own hands and applying cures according to the USA Government requirements.

In case you want to be the professional, we are enclosing some useful data which is based on the U.S. standards. Comminuted products  small meat pieces, meat for sausages, ground meat, poultry etc. Cure #1 was developed in such a way that if we add 4 ounces of Cure #1 to 100 pounds of meat, the quantity of nitrite added to meat will conform to the legal limits (156 ppm) permitted by the Meat Division of the United States Department of Agriculture.
That corresponds to 1 oz. (28.35 g) of Cure #1 for each 25 lbs. (11.33 kg) of meat or 0.2 oz. (5.66 g) per 5 lbs. (2.26 kg) of meat.
Comminuted Meat (Sausages) 
Cure #1 in ounces 
Cure #1 in grams 
Cure #1 in teaspoons 

25 lbs. 
1 
28.35 
5 
5 lbs. 
0.2 
5.66 
1 
1 lb. 
0.04 
1.1 
1/5 
1 kg 
0.08 
2.5 
1/2 
Cured dry products  country ham, country style pork shoulder, prosciutto, etc. These products are prepared from a single piece of meat and the curing ingredients are rubbed into the surface of the meat several times during the curing period. Nitrite is applied to the surface of the meat or poultry as part of a cure mixture. If you look at the FSIS nitrite limits table on page 36 you will see that the maximum nitrite limit for Dry Cured Products (625 ppm) is four times higher than for Comminuted Products (156 ppm).
To cure meat for sausages (comminuted) and to stay within 156 ppm nitrite limit we have to apply no more than 1 oz of Cure #1 for each 25 lbs of meat. To dry cure 25 lbs of pork butts and to stay within 625 nitrite limits we need 4 times more of Cure #1, in our case 4 ounces. Keep in mind that when you add Cure #1 (there is 93.75% salt in it) you are adding extra salt to your meat and you may readjust your recipe.
Meat for Dry Curing 
Cure #1 in ounces 
Cure #1 in grams 
Cure #1 in teaspoons 

25 lbs. 
4 
113.4 
20 
5 lbs. 
0.8 
22.64 
4 
1 lb. 
0.16 
4.4 
3/4 
1 kg 
0.35 
10.0 
1.5 
The reason that there are much higher allowable nitrite limits for dry cured products is that nitrite dissipates rapidly in time and the dry cured products are air dried for a long time. Those higher limits guarantee a steady supply of nitrite.
Immersed, Pumped and Massaged Products such as hams, poultry breasts, corned beef. Here, it is much harder to come up with a universal formula as there are so many variables that have to be determined first. The main factor is to determine % pump when injecting the meat with a syringe or % pickup when immersing meat in a curing solution. We will calculate the formula for 1 gallon of water, Cure #1 and 10% pickup gain. Then the formula can be multiplied or divided to accommodate different amounts of meat. 10% pump or 10% pickup mean that the cured meat should absorb 10% of the brine in relation to its original weight. For immersion, pumped or massaged products, the maximum ingoing nitrite limit is 200 ppm and that corresponds to adding 4.2 oz of Cure #1 to 1 gallon of water.
Amount 
Cure #1 in ounces 
Cure #1 in grams 
Cure #1 in teaspoons 

1 gallon (8.33 lbs) of water 
4.2 
120 
20 (6 Tbs) 
This is a very small amount of brine and if you want to cure a large turkey you will need to increase the volume. Just multiply it by a factor of 4 and you will have 4 gallons of water and 1.08 lbs. of Cure #1. The following is the safe formula for immersed products and very easy to measure: 5 gallons of water, 1 lb. of Cure #1. In the above formula at 10% pickup the nitrite limit is 150 ppm which is plenty. Keep in mind that adding 1 lb. of Cure #1 to 5 gallons of water will give you 4.2% salt by weight and that corresponds to only 16 degrees brine (slightly higher than sea water). If we add an additional 2 lbs. of salt we will get: 5 gallons of water, 1 lb. of Cure #1, 2 lbs. of salt and that will give us a 25 degree solution which is great for poultry.