Igor,
..further thoughts on cure #1 vs. cure #2 and the role of antioxidant. I apologize in advance for being long-winded.
First, let's clear up a fundamental item. The writeup for cure #2 at Sausagemaker website
http://www.sausagemaker.com/10108instacure24oz.aspx says, in part:
"...a cure specifically formulated to be used for making dry cured products such as pepperoni, hard salami, genoa salami, proscuitti hams, dried farmers sausage, capicola and more. These are products that do not require cooking, smoking, or refrigeration. Insta Cure™ No. 2 can be compared to the time release capsules used for colds--the sodium nitrate breaks down to sodium nitrite and then to nitric oxide [actually nitrous oxide, N2O] to cure the meat over an extended period of time. Some meats require curing for up to 6 months. InstaCure #2 contains salt, sodium nitrite (6.25%) and sodium nitrate (1%)."
So, please note that
Cure #2 contains BOTH nitrite and nitrate. In this formulation, cure #2 is equivalent to cure #1 plus 1% nitrate. Also note their statement that the reaction goes from nitrate to nitrite, and is rate-limited, not equilibrium-limited.
As to
"nitrite during the curing process will generate a `pool` of nitrate,"
this assumes that the reactions are reversible and that some sort of equilibrium is reached. However, sodium erythorbate is described as an accelerant, which implies a forward reaction rate. Only if the nitrate and nitrite were close to being in equilibrium would there be an appreciable amount of nitrate generated by the reverse reaction.
What you are probably referring to when you speak of a "pool" is the case of
several reactions in series. (I`m much more current on this, having worked on chemical process simulations for much of my engineering career.) Nitrate produces nitrite, which produces nitrous oxide, which is consumed. Here is a reaction scheme, as diagrammed at
http://en.wikipedia.org/wiki/Nitrite
Nitrate-goes to nitrite:
. . . . . . . . .NO3- + 3H+ + 2e <-> HNO2 + H2O
Nitrite then generates nitrous oxide by a series of steps:
. . . . . . . . .2HNO2+ 4H+ + 4e <-> H2N2O2 + 2H2O
. . . . . . . . .N2O4 + 2H+ + 2e <-> 2HNO2
. . . . . . . . .2HNO2+ 4H+ + 4e <-> N2O + 3H2O
...which is what reacts with the myoglobin, as we are often told. Indeed, these are shown as reversible reactions. However, because N2O is consumed, everything flows to the right, the nitrate being consumed to maintain the supply of nitrite or, if there is no nitrate present, the nitrite is consumed preferentially to produce N2O as it is consumed.
If you look up the Wikipedia writeup, you`ll see so-called "reduction potentials" listed. Fortunately for our readers, my last thermo course was over forty years ago, so probably neither of us should go there. Let`s just say that it`s possible to drive the reverse reactions, but only at considerable cost of energy. What's more important is that product N2O is being consumed, driving the reactions to the right.
If you start with nitrate only and the reactions proceed, a pool of nitrite (not nitrate) will build up, but only enough that the rate of nitrite production equals the rate of nitrite consumption. (If you start with both nitrate AND nitrite, the pool is already there.) As the nitrate starting material is consumed, the reaction rate to nitrite drops because concentration drops. The nitrite intermediate continues to react to the final N2O product, but the concentration of intermediate falls, reducing its rate.
The net result is that a pool of intermediate nitrite grows, stabilizes, then declines. In this case, where final product is all consumed, both the nitrate and the nitrite concentrations go essentially to zero too.
To generate a pool of nitrate, the nitrate-nitrite reaction would have to run in reverse. The reduction potentials suggest that the reverse rates are pretty slow. Yes, it IS possible, but not worth arguing over. (Don`t let me get into lecture mode!) Whether or not there is a pool of nitrate generated, please accept that, in a series of reactions where the product is removed, eventually the starting material and all intermediates will also be consumed.
You mentioned:
"However when using a very fast fast starter culture there won´t be time enough for the nitrate reduction and that is why cure #2 should not be used in this instance!"
I believe you are correct. All the recipes that I have seen agree with you. The fast reactions get the sausage into conditions hostile to further bacterial growth, so nitrate protection is no longer necessary. (However, nitrite protection IS necessary during that short period of time when the "good" bacteria dominate and do their work. This is why cure #2 contains both nitrate and nitrite.) Note that this is a rate-governed reaction, not an equilibrium condition. This suggests that the reaction of nitrate to nitrite is (under the conditions where we operate) irreversible.
You also mentioned:
"topple the amount relation between the nitrite/nitrate and the anti-oxidant"
I`m not sure what you mean, here. The anti-oxidant accelerates conversion of nitrate to nitrite, and if the mixture is not uniform, pockets of high nitrite might well occur. Best advice from both you and me about adding too much: "Don`t do that!" (Follow the directions.)
I apologize for my long-winded, obscure chemical logic. It`s a case of "too much education without a helmet" perhaps. (...or perhaps Chuckwagon's style is rubbing off on me? Aarrgghh!) Unlike Chuckwagon, though, I have difficulty explaining these things to the general public. Perhaps we should have done this off-line, so as not to make our forum members dizzy.
Best regards,
Duk
