NCPaul
Thanks for your advice I will contact the local laboratory after the holiday. The information about them says:
Leicestershire and Staffordshire Scientific Services is an efficient and reliable scientific service offering testing and analysis, advice and support to customers in the public and private sector.
We have four Public Analysts, thirty-five well-qualified, experienced staff and two laboratories, based in Leicester and Stafford, accredited to UKAS Quality Standard ISO/IEC 17025 which are both Official Food Enforcement Laboratories
They are accredited for nitrite/nitrate testing as well as the normal chemical thingies, but I'm guessing that testing for salt levels will be cheaper?
Funnily enough they are about 300 yards from where I used to work - but I didn't even know they were there!
OddleyThank you for you continuing contribution to this problem.
My position on 'Method 2' is that it is for use with small pieces of meat or meat cured fully to equilibrium - pieces of meat that have a large surface area in relation to the weight/thickness of the meat. We know that the method works - NCPaul has shown this with his tests on a 1kg piece of meat.
As to where 'Method 1' takes over? I don't know.
I appreciate that your method of calculation attempts to produce a correlation between the two methods, or at least tries to project the outcome for larger pieces of meat, or meat cured for less time than it takes to reach equilibrium, from Method 2. Whether or not based on NCPaul's research, your model and his are similar.
My point is that if this is a way to do it why did the US scientists come up with Method 1 for calculating larger pieces of meat? Logically you would only need to add a ratio of weight:cure time to the Method 2 equation to cover all eventualities and avoid confusion.
I believe it unlikely that they would have come up with two methods if:
1. Both weren't needed.
2. They didn't both work for the applications they suggest.
As such I believe that their advice...
Method One is used for hams, shoulders, bellies, etc., because it takes weeks for these
large items to reach equilibrium. Method Two is primarily used with small items with large
surface areas such as pigs' ears, tails, snouts, etc.
...should be followed. As long as the meat is very small or very large this seems 'clear cut'.
That's my position on Method 2, but in this case we are pumping the meat, followed by a (short) brining. A standard practice used by curers for years as you explained to Dougal in 2006:
Oddley wrote:Dougal wrote:I don't have Oddley's practical experience, but injecting 10% and immersion curing seems OTT to me. But I don't have the practical experience.
Butchers use this method, or so I have been told by butchers, who am I to argue.
If the meat has been pumped it has uneven amounts of brine/ pickle in it, so needs at least a few days to equalize. It has also probably not been pumped near the surface, so there is a large amount of meat without brine/pickle. If the meat is immersed it will cure from the outside and the inside, which will speed the cure, whilst being kept bacterially safe. If you remember the hurdle concept of safety has been discussed.
If you have some proof of another method that is as quick and bacterially safe then I would love to see it, as it would be cheaper than the present method. Butchers would be all for that.
I suppose we could do it like the commercial manufacturers and just pump it full then vac pack it.
I didn't learn how to cure to make my stuff the same as commercial manufacturers. I prefer to take a bit more time and make a bit more of an effort to perhaps produce a better product. Or I might as well just go down Tesco's and buy some ham or bacon.
However, our knowledge of the curing process has moved on since then, but I doubt that the methods used by many butcher's will have. It's somewhat ironic that here we are, a bunch of amateur curers who are more concerned about curing safely than the guys who actually have the opportunity to poison people (gradually) daily!
Right, to this piece of meat, the pump element - we are in agreement about calculating this, other than maybe allowing for 'seepage' it's fairly clear cut. However, The answer may lie here - I'll return to it later.
We then have the immersion element. You contest that the piece of meat will pick up the same amount of salt in one week as it would if the 6kg had been immersion cured and calculated on a 'pro rata Method 2' basis:
Oddley wrote:
As you can see, with just the 10% pump you get 2.0% salt. I did a percentage to equilibrium calc to find that there would be a 1% pickup of salt in 7 days, therefore the total ingoing would be about 3.0% salt.
What I'm saying is that:
1. I haven't a clue as to the proper method of calculation, but I don't believe that anyone else on this forum has a definite answer either.
2. Although your method of calculation is logical (and akin to how I'd have thought it should be done) there is no basis for doing it using Method 2 in the FDA handbook as it is not cured to equilibrium nor can NCPaul's tests on a small piece of meat be safely extrapolated to be used on a piece of 6kg.
3. The immersion cured calculation according to the US advice should be Method 1 not Method 2.
4. The fact that it has 'absorbed' 10% of it's weight in brine already is likely to have some effect on the process.
5. That the ham doesn't taste as if it has 3% salt (subsequently reinforced by taste tests by five people).
6. The time taken to reach equilibrium may be longer than you think. Paul's 1 kg piece wasn't at equilibrium in 11 days, whilst the average salt was very near, the centre was way off being stage where "levels in the tissue and in the pickle are balanced." (FDA definition)
However I accept that when talking in relation to combined curing that the FDA seem to back your position:
In Black Forest Brand Hams that are pumped and then immersed in a cover pickle solution, the limits are the same (200 ppm for nitrite, 700 ppm for nitrate). Therefore, if 200 ppm nitrite is used in the pumping process, no additional nitrite is permitted in the cover pickle. If 350 ppm nitrate (or 50% of that permitted) is added to the pump cure, up to 350 ppm nitrate (the other 50%) is permitted in the cover pickle.
The answer to as to why a ham doesn't behave as expected may lie in how the FDA advise to calculate the % pump/pick-up:
If a drain time is listed in the establishment's approved procedure, allow the pumped/treated product to drain for the specified time period and then weigh. If no drain time is listed, take the weight directly after pumping.
I only weigh before and after curing so don't have a % gain 'after drainage' - but it is apparent that some occurs. Also the weight gain after curing for this method varies between 5% and 9% (from my records) against 10% injected. I accept your premise that much of the loss of injected cure may be water (although we have no evidence, so we may both be wrong). However, it seems impossible that all the injected salt will detach itself from the water and move into the meat. (I guess that the Nitrite will be different due to it's reaction in the meat - that's another issue, but of more concern). This would go some way to explaining why the finished product doesn't perform as you expected it to.
I would stress, I don't claim to know the answer and I certainly don't want this to degenerate further into a petty competition as to who's correct in a discussion that relates to 1% of salt. I'm approaching it with an open, but enquiring/challenging mind.
Anything that progresses our knowledge of how cures work and enables us to calculate them more accurately interests me, I'm really hoping I can find some way of getting tests done cheaply to assist this process. Maybe you could enquire in your area - I would think that it may be a more competitive market where you are?
Phil