Cure #2
Also known as Prague Powder #2, Insta Cure #2
The long-cure salt, Cure #1 with a nitrate reservoir added, for dry-cured products aged over weeks and months.
Cure #2 is Cure #1 with a reserve of nitrate folded in: the same 6.25 per cent sodium nitrite, plus about 4 per cent sodium nitrate, in salt. The nitrite sets the cure going at once; the nitrate then breaks down slowly, over the weeks and months of a long ripening, into a renewed trickle of nitrite. It is the difference between a single charge and a slow drip.
That drip is exactly what a long dry-cure needs. A dry-cured salame or a whole-muscle coppa spends months losing water and developing flavour, far longer than a single dose of nitrite would keep protecting it, so the nitrate reservoir of Cure #2 keeps a little fresh nitrite present the whole way through. For the same reason it is wrong for quick or cooked products: there is neither the time nor the cool, patient conditions for the nitrate to reduce.
It is used like Cure #1, weighed to the recipe at 0.25 per cent of the meat, 2.5 grams a kilogram, with the balance of the salt added separately, and it shares the same absolute rule against casual substitution. Its European counterpart is Salvianda, which carries the same idea, nitrite plus a nitrate reservoir, at the low strength of a nitrited salt used pure as the whole salt; the two reach the same end by the two different delivery models. The nitrate reservoir is a tool for the long haul, not an upgrade to be dropped into a bacon or a fresh sausage.