I assume you had the meat in the refer..... The refer was too cold.... temp should be 38-40 deg F.... Meat should not be over 2" thick when using a rub with cure.... When making BBB, I recommend removing the shoulder blade and curing each half separately.... Rubbing each half with cure and spices, on both sides, to insure full penetration in the meat.... After the recommended curing time, letting the meat rest in the refer for several more days, will further allow the cure to penetrate and equillibrate inside the meat...
When you rub the meat with cure and spices, the outside of the meat has 62,500 Ppm nitrite on it... the center has 0 Ppm nitrite... letting adequate time to pass, for equilibrium to take place, is essential for a uniform cure to take place...
I think the rule of 1/4" per day penetration + 2 days, is "fair", at the proper temps... but additional time must be allowed for the reasons stated above...
The same applies for placing meats in a brine.... although, thicker slabs of meat require "pumping or injecting" into the meat muscle so cure is penetrating from all parts of the meat....
Dave
