FDA Processors calcs.Is method one viable for home curers.

Air dried cured Meat Techniques

FDA Processors calcs.Is method one viable for home curers.

Postby captain wassname » Mon Nov 09, 2009 12:38 am

Up for dicussion I dont believe that calculations based on method 1 are viable for home curers.

We have the pick up percentage which as far as I can see is like a politcians promise ,merely aspirations ,and a premise that it is impossible to pick up more than the level of cure that is in a solution which is patently not so.

Jim.
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Postby saucisson » Mon Nov 09, 2009 1:09 am

I'm not clear what you are saying Jim. No disrespect to anyone else, but can you state in simple words what you are suggesting?

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Postby captain wassname » Mon Nov 09, 2009 2:11 am

In short Im concerened that percentage pick up which is stated in the calculations to be x% and the only way we can determine this is by weight

weight before immersion =x weight after immersion=x+10% means a 10% pick up. so the brine is made up on that assumtion

There is no mention of time. we might just easily say we are aiming for a 2% pickup and add more cure the calculation

Time is important because we suspect that we will cure to equillibrium at the rate of about 10 days per kilo and yet no where in method 1 calcs is time mentioned merely weight.
I do hope this post opens a fruitful discussion.

Jim
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Postby wheels » Mon Nov 09, 2009 12:37 pm

Jim

You are correct that we can't calculate an exact figure of pick up, any more than we know how much of the cure stays in an injected piece of meat, or how much cure is absorbed by a dry cured piece of meat.

It certainly can't be done by weight as juices will be leaving the meat as cure enters, how much of each is anyone's guess - unless that is you have the know how/equipment to test for levels of salt etc.

Funnily enough, I am far happier with method 1 than method 2, which only seems to appear with reference to the US rules. (having said that, other countries don't seem to publish calculation methods).

It would certainly be interesting to see the results of analytical tests (trading standards?) carried out on products made by each method.

However, in their abscence, I guess that what I'm saying is that there are times when, having reviewed the evidence presented, you just have to trust the scientists.

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Postby jane » Mon Nov 09, 2009 2:03 pm

Dear Jim,

I wondered if surface area of the meat would also affect pickup - the greater the area of meat in contact with the brine the more pickup there would be?

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Postby wheels » Mon Nov 09, 2009 3:35 pm

captain wassname wrote:Time is important because we suspect that we will cure to equilibrium at the rate of about 10 days per kilo and yet no where in method 1 calcs is time mentioned merely weight.
I do hope this post opens a fruitful discussion.

Jim


Time is important if the US scientists are to believed, but they tell us that method 1 is to be used for hams, shoulders, bellies, etc., because it takes weeks for these large items to reach equilibrium. Whether equilibrium is reached at 10 days per kilo or not, we can only assume that if normal curing times are used for these items that they do not reach equilibrium, otherwise there wouldn't be a need for method 1 at all. (A method to calculate a brine for a cure that would leave the meat partially uncured being nonsensical!).

jane wrote:Dear Jim,
I wondered if surface area of the meat would also affect pickup - the greater the area of meat in contact with the brine the more pickup there would be?
Jane


This seems to be true, the FDA handbook actually says; "Method Two is primarily used with small items with large surface areas such as pigs' ears, tails, snouts, etc.". But then on the other hand we are told that pork bellies should be be calculated to method 1 - they seem to have a very large surface area. It would appear that it is a combination of size and surface area that is crucial. It seems to be akin to a small bird freezing to death when an elephant wouldn't, even though the elephant has a larger surface area - sort of a weight x surface area ratio. I'm sure there is a name for this, but it eludes me.

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Postby Oddley » Mon Nov 09, 2009 5:56 pm

Lets first of all remind ourselves, what a method 1 calculation is.

FDA wrote:Method One

The first method assumes that the meat or poultry absorbs
not more than the level of nitrite in the cover pickle.

Hence, the calculation for nitrite is based on the green weight
of the meat or poultry (as is the case with pumped products), but uses percent pick-up as
the percent pump. The percent pick-up is the total amount of cover pickle absorbed by
the meat or poultry. It is used in the calculation for immersion cured products in the same
way percent pump is used in the (previous) calculation for pumped products.


    Image


I think what they are saying with the 8 - 10% absorption rate of pork, is that pork will reach a saturation of chemicals at 8 - 10% it's own weight. I know all of you know about dissipation and osmosis, so no need to go into the science of it. The most important thing is to know when you have reached the curing level that your cure has been designed to achieve. I'm not a great fan of the immersion curing method, that uses time to asses the amount of cure absorbed, as I reckon it can be out at as much as 5%. On the other hand with a carefully constructed cure this is not going to matter that much.

As for the 10 days per Kilogram of meat curing time, I was a little out, the correct time is 8-9 days per Kg meat, or 11 days per inch thickness. according to Oklahoma State University.

Oklahoma State University wrote:Curing time for hams and picnics in brine is 3 1/2 to 4 days
per pound per piece of meat. Another way to figure curing
times is to allow 11 days per inch of thickness measuring the
greatest thickness through the center of the cut. A 15 pound
ham will take 60 days to cure by the immersion cure method.

    Here.

After all, even some commercial outfits use the simple immersion cure method. We had a big topic about black bacon and ham, the producers of that used this method. I think the main thing is, think about your cure carefully and know what you are doing, or seek advise.
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Postby jane » Mon Nov 09, 2009 9:07 pm

I am not at all sure I really understand what is meant by % pickup. In the example I gave of a cure that by method 1 with a pickup of 10% the result is 146.5 ppm. If you use method 2 which takes in to account the weight of meat - and assumes reaching a state where the concentration gradient for nitrite has levelled out (equilibrium) the result is radically different.

6 litres liguid
930g salt
720g sugar
198g cure 1 (11.5g Na Nitrite, 186.5g salt)

for a 7kg ham:

method 1
11.5(nitrite) x 0.1 (% pickup) x 1,000,000/ 7848 (weight of brine) =146.5 ppm

method 2
11.5 x 1000,000/(7848 + 7000) = 774.5 ppm

For a 7kg ham to reach equilibrium would take (at 8 days per kg) 56 days but the concentration gradient would mean that the greater part of the transfer of solutes would take place early on in the brining time. What I do not understand is how, in the method 1 example above, you know when the right time to take the ham out of the cure is - or, to put it another way, how you know the speed of the transfer of solutes in to the meat and the rate that that speed changes as the concentration gradient changes. For me putting 198g of cure 1 in to the brine is worrying if I do not know with some certainty when 146.5 ppm or thereabouts has been reached.

Can any one help or perhaps explain where my thinking is wrong?

Jane
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Postby captain wassname » Mon Nov 09, 2009 9:39 pm

Hi Sorry to be so tardy

Jane I would imagine that a piece with lage area would pick up more quickly initially but dont think it would pick up more over time

Phil the bit that gets me confused is that as you say Method 1 is a method to cure quicker and as sush must of necessity comtain more cure. which comes back to time or weight.
The weight thing came from Chapter 11 p76 to83 page 79states When perfoming gain tests to ensure added solution compliance the inspection program employee should use the same unpumped or treated pieces of meat ot poultry to determine the % gain(I take treated to include immersed) it then goes on to say that
The inspection program employee may select and weigh pumped or treated pieces of meat or poultry.
So the FDA rely solely on weight.
I assume that the manufactures have already done analysis on various pieces of meats and levels of cure so they know how long it will take to achieve their desired % pick up. They then ask for and are granted permission to cure and they need quality control to check random pieces.
Unfortunatley there are no worked examples so we have no clue as to a time line or the amount of pick up that might typically be expected.(when they talk of pumping ther frequently mention 25%) We cant tell from the manual wether the hams are weighed daily or not but I get the impression that they are weighed just the once.

Jim
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Postby wheels » Tue Nov 10, 2009 12:58 am

Jim

I doubt they even weigh once. They're probably on minimum wage and just do as they're told!

As to the rest of your and Jane's posts, If you don't mind, I will reply to them later.

I would, however appreciate other input; whilst I am happy to discuss this, most forum member's will be aware that I don't immersion cure for the very reasons you have raised.

Phil
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Postby captain wassname » Tue Nov 10, 2009 11:55 am

Jane Sorry I wasnt ignoring you Its just takes me so long post as I am not too good with words and have limited keyboard skills . Method 2 is essentsially an equillibrium cure and cures calculated by method 1 are meant to enable you cure in a shorter time. percentage pick up is the amount of brine that you estimate a piece of meat will take up in effect the equivilant of a percentage pump Thats as far as I can enlighten you

Phil Im not having a go at you Its just thatI would like to immersion cure but Im loath to do anytthing I dont understand and there seem to be too many variables,especially if like me you are using smaller joints (which to be fair is not what cures calculated by method 1 are designed for)

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Postby saucisson » Tue Nov 10, 2009 12:34 pm

I've just spent the last 24hrs tucked up in bed so apologies if I was being particularly dense on Sunday night/early Monday.

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Postby wheels » Tue Nov 10, 2009 4:39 pm

Jim/Jane

I don't like the ambiguity that having 2 methods of calculation gives any more than you; as I have stated on many occasions. I too have tried to work out where one method ends and the other starts, but without a dialogue with the people that researched this, I doubt we will ever know.

I have come to the conclusion that we can't make suppositions about what the instructions mean - as Jane points out, the results are wildly different from each method which appears to be related to time in cure (along with weight, shape and surface area!).

Interestingly I note that Maynard Davies, writing in his recent book, only cured even large pieces of meat for a couple of weeks in brine cure and then 'completed the curing' by hanging the meat - a short cure, followed by a long equalisation period. I also know from experience that hocks etc cure very quickly.

I know it was quite a shock to many of us to learn that meat would reach an equilibrium with the cure - prior to this we had always assumed a 8 - 10% pick up and calculated to method 1.

If we trust the scientists we should still use this method for large pieces of meat - that's what the guidance tells us. As I said before, we must trust that a 'normal' curing time will not result in equilibrium - that's what they are telling us and as I said before, if this wasn't the case and equilibrium was reach during a normal curing time, then method 1 would be redundant.

We also don't have a problem with very small pieces of meat with a large surface area, we are told to use method 2.

What I find odd is that we are told to cure belly to method 1 - yet this seems to have a large surface area even though it may weigh quite a lot. We can only deduce from this that to use method 2 both criteria (small and large surface area) must be met.

The problem seems to arise in that, unlike commercial curers, home curers often want to cure just a small chunk of meat, say around 2 kg. On the one hand this is unlikely to have a large surface area, but it is small. If my theory about a weight x surface area is correct we would probably use method 2 - the fact that people have done this, thereby using a minimal amount of cure, and found that the meat is adequately cured, seems to indicate that this may be the way to go. However, we should not ignore the risk of under-curing the meat, something that concerns me more than 'over-curing'. Some of this can, of course, be mitigated by ensuring a brine concentration of over 10% which will give added protection during the curing period.

Personally, I would only use immersion curing either for large pieces of meat (method 1) or very small pieces (method 2) - for anything in-between I would either dry or injection cure.

Phil
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Postby NCPaul » Tue Nov 10, 2009 5:01 pm

I will do an experiment. You will have to wait for the weekend, so be patient. I will try to post data daily.
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Postby Oddley » Tue Nov 10, 2009 6:08 pm

I think you blokes have misunderstood the term 10 % Pickup. This term refers to sodium chloride, nitrites and other water soluble chemicals, so if the brine does not have enough chemicals in it to give an equilibrium of more than 8 - 10% of these chemicals, then it won't pick up 8 - 10% it's own weight.

All this about weighting, is nonsense, as up to 100g salt per litre water, ie: chemicals, the meat will gain weight and as far as I'm concerned, not in a linear fashion, after that gram per litre water, the meat will lose weight.


In my humble opinion method 1 and 2 are the same and can be used interchangeably, the only variable being the time.

Work out your cure for how much concentration you want ie: 3 x the amount you want to reach equilibrium, then cut the curing time down to a 3rd of that needed for equilibrium using the 8-9 days per Kg or 11 days per inch for really thick pieces. After curing, leave in the fridge or hang for a week or two to equalize the cure.

It has taken a lot of research and thinking to come to this point. I am happy to cure using these methods and techniques, using common sense for meat size and thickness as my guide.
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