Immersion Curing - Surface Area

[wheels]

Thanks to NCPaul we have a profile of the movement of salt, and presumably cure, into a 1kg piece of meat. From that we have been able to calculate cures for immersion brines more accurately (we hope!).

Has anyone looked further into the how the surface area of the meat, or the surface area not covered by fat/skin, may affect the absorption of brine/salt etc?

For example, we presume that in 10 days 1kg of meat will be 85% towards equilibrium and that it will reach 50% in as little as two days. Does this necessarily mean that 2kg will reach the same point in 20 days?

Will the respective surface areas affect this?

Given that many of us use boned & rolled meat which tends to be cylindrical in shape, doubling the weight (i.e. using a piece twice as long) will not double the surface area. In fact the surface area will probably only increase by 50% of the original. Furthermore, if the meat is covered with fat/skin on the top and sides (and that we accept the premise that cure will not be absorbed as efficiently through this), the increase in surface area available for cure to penetrate through will have increased by even less.

Will this mean that it will take longer than 2 days per kg for larger pieces to reach 50% equilibrium, or more than 10 days per kg to reach 85% equilibrium?

Could it even be that 85% equilibrium will still be reached in 10 days per kg, but that the progress towards this will spread more evenly over the period?

Your observations/views would be appreciated.

Phil

[quietwatersfarm]

This is an area that I am still out of my depth with! (:roll:)

I can see that we could simply apply maths to it, based on the results from NCPaul et al and your own apparently logical presumptions above, and trust this would give us a reasonably safe estimate.

That said I am not sure I ever got my head around the logic, or to my mind the lack of it, in the guidance (which I think sparked much of last years discussions) that seemed to abitrarily confuse both weights and surface areas.

A big (therefore heavy and large surface area) piece of meat will surely reach equilibrium in less time if it is an inch thick compared with a lighter and smaller surfaced but thicker chunk?

The upshot is that my head now hurts but I cant wait to hear from the experts (Cue Oddley!)

[Oddley]

The upshot is that my head now hurts but I cant wait to hear from the experts (Cue Oddley!)

Thank you quietwatersfarm, but I really don't consider myself an expert. I have been thinking about this point though. Before applying it I want to wait for the results of NCPauls latest experiment, I will let him explain why in the fullness of time.

My take on this is the best way forward and putting my neck out (as usual), I think that I will measure time for an immersion cure in 2 day's per cm thickness of meat. So for a leg of 6"" or 15 cm, the leg would be in cure for 30 days. a belly 5 cm would be in cure 10 days. Does this make sense to anybody. The maths for the cure would have to be worked upon, but I think this timing treads a fine line between taking forever and under curing.

Of course there will have to be the requisite equilibrium time in the fridge.

[wheels]

Thank you both for replying.

Before applying it I want to wait for the results of NCPauls latest experiment, I will let him explain why in the fullness of time.

I look forward to seeing more of NCPaul's research, it really progresses the little knowledge of this subject that we have.

My take on this is the best way forward and putting my neck out (as usual), I think that I will measure time for an immersion cure in 2 day's per cm thickness of meat. So for a leg of 6"" or 15 cm, the leg would be in cure for 30 days. a belly 5 cm would be in cure 10 days. Does this make sense to anybody. The maths for the cure would have to be worked upon, but I think this timing treads a fine line between taking forever and under curing.

Is this to cure based on calculations that assume full equilibrium being reached in this time.

The inference is presumably that a piece of rolled leg twice the weight as another, but just longer rather than wider, will cure in the same time as a piece half the size? i.e. That it's the distance the cure has to travel, rather than the meat's weight that governs cure times?

Of course there will have to be the requisite equilibrium time in the fridge.

Yes, I was surprised how little had reached the centre in NCPaul's last tests. I think that a lengthy period of equalisation may be essential for this type of cure.

You've raised some really interesting and though provoking issues there Oddley, I look forward to you expanding on them.

Phil

[Oddley]

I'm really not prepared to go further, pending the results of the experiments being conducted by NCPaul. But I hope we can agree, that measuring curing time by weight is a little inaccurate and curing times by thickness is perhaps the way forward.

[saucisson]

My thoughts are that the figures will be completely different for a 1kg sphere, a 1 kilo cube and a 1 kilo strip, for penetration. Whether the surface is meat, skin or fat will also affect. Equilibration is another factor to consider. Curing relies on conversion of nitrate/nitrate to NO2 by bacteria, this is time dependent regardless of the size or surface area, but they may have huge effects on the numbers of bacteria present...

I'm not sure this is something we can completely pin down... But we can establish boundaries, I hope...

Thickness seems the logical way to go...

[quietwatersfarm]

Its apparent that a consensus is emerging.

Its always bothered me that a 6Kg, 15cm diameter cylindrical ham should take twice as long to cure as a 3 Kg one of the sime shape and diameter.

Perhaps another relevant factor might be distance to a centre point?

[wheels]

Do you have any idea when these test results are expected?

Phil

[saucisson]

Its apparent that a consensus is emerging.

Its always bothered me that a 6Kg, 15cm diameter cylindrical ham should take twice as long to cure as a 3 Kg one of the sime shape and diameter.

Perhaps another relevant factor might be distance to a centre point?

May well be, also: what if cure penetrates faster along muscle groups than across them ?

[Oddley]

saucisson, if that were the case I would expect less bone sour and less than a 25% discard rate in professionally made Parma Ham. Good idea though!

[NCPaul]

I plan to start soon. One will be a big piece and may take a couple of months plus I'm slow.

[wheels]

Can you give us an idea of what you are going to do Paul?

Phil

[saucisson]

saucisson, if that were the case I would expect less bone sour and less than a 25% discard rate in professionally made Parma Ham. Good idea though!

Thanks

[captain wassname]

Immersion cure surface area.
Sorry about the long inactivity on this subject but I do need time especially when dealing with speculation So given time I will speculate.

My understanding of calculation of uptake of cure in an immersion inviroment is that there are things to be taken into consideration mainly these include mass,surface area and what I think Charles called convection.(the sudden influx of cure into the meat)
I think that we can more or less agree that there is a sudden influx of cure and that 50% of equilibrium per kilo may take place in 24 hours.

The surface area of a given piece of meat will make some difference to this initial uptake but not not by more than an hour or two.
In other words my argument is that the initial path to equillibrium is governed more by mass rather than surface area.
So if we accept that the curing of the first kilo of a piece of meat is accompolished within 1 day and then consider the relative surface area it would seem logical to conclude that the depth of "cure penitration" would be a lot less for a a thin piece of meat.
It also seems that thinner piece of meat may reach equillibrium somewhat sooner once the slower phase kicks in but not so much ,with any certainty, as to change our minds about the 10 day cure that we have suggested.
The 10 day cure was a compromise which in my opinion would ensure that thin pieces were not overcured and fat pieces would not be undecured.
I speculate that it is probable that a shorter period of time is needed for thinner piece to equalise.

[captain wassname]

Immersion cure surface area.
Sorry about the long inactivity on this subject but I do need time especially when dealing with speculation So given time I will speculate.

My understanding of calculation of uptake of cure in an immersion inviroment is that there are things to be taken into consideration mainly these include mass,surface area and what I think Charles called convection.(the sudden influx of cure into the meat)
I think that we can more or less agree that there is a sudden influx of cure and that 50% of equilibrium per kilo may take place in 24 hours.

The surface area of a given piece of meat will make some difference to this initial uptake but not not by more than an hour or two.
In other words my argument is that the initial path to equillibrium is governed more by mass rather than surface area.
So if we accept that the curing of the first kilo of a piece of meat is accompolished within 1 day and then consider the relative surface area it would seem logical to conclude that the depth of "cure penitration" would be a lot less for a a thin piece of meat.
It also seems that thinner piece of meat may reach equillibrium somewhat sooner once the slower phase kicks in but not so much ,with any certainty, as to change our minds about the 10 day cure that we have suggested.
The 10 day cure was a compromise which in my opinion would ensure that thin pieces were not overcured and fat pieces would not be undecured.
I speculate that it is probable that a shorter period of time is needed for thinner piece to equalise.