Seriously, the concept is that given time the meat and brine become one system:
Inspectors' Handbook wrote:The second method assumes that the submerged meat, meat byproduct, or poultry and the cover pickle act as a single system. Over time, the ingredients in the pickle, such as nitrite and salt, migrate into the meat, meat byproduct, and poultry until levels in the tissue and in the pickle are balanced. This system is actually very complex and dynamic, with components in constant motion, but it will reach and maintain a state of equilibrium.
As such, it is the amount of meat in 'the system' that's material. Or that's the way I think that we saw it.
There's no doubt that this system of curing is best for smaller rather than larger amounts of meat - something I pointed out on my black ham recipe, but I omitted on the cider ham, as BriCan has highlighted.
To professional curers it may seem a kerfuffle, but like the equilibrium dry curing method before it, it is a pretty foolproof way for the home curer to get good (and consistent) results with brine cures. It also has the advantage of using a lot less curing salt, a consideration in countries where this is an fairly expensive commodity.
Phil