Following a couple of recent threads where the uptake properties of Nitrite by bacon was debated at great length (with a little more vigor at times than I was expecting), it became clear that there were certain assumptions that were being used to calculate the uptake of Nitrite in bacon when immersion curing that had little credible supporting evidence. Whilst there is no reason to doubt the validity of these assumptions there also appears to be little laboratory based evidence to support them either. The assumption that appears to have the least supporting evidence so far, and I hope to validate, is that when the pork is immersed in the concentrated curing brine, 10% of the cure concentration in the brine will be taken up by the meat.
There was also a big difference in the methodologies of some of the recognised authorities on curing here on the forum - with two of them recommending very different starting concentrations of cure. To try to verify both of these methodologies I am going to compare both methods, as published on here, using laboratory techniques and at the end of the process have all of the samples analysed for residual Nitrite at a government licensed food safety laboratory. I am fully expecting both methods to result in a "safe" end product (one that falls within the governments maximum and minimum limits for Nitrite), however I am expecting them to probably be at either ends of these limits.
So that I can maximise the value of the testing I have outlined the methodology that I intend to use below. This will give other forum members the opportunity to comment on the process before it begins. No testing will be absolutely perfect and test all possible variables but I am looking to test the major assumptions first - and these may be refined further in future testing.
As the commonly used cuts of pork used for bacon on here are Belly and Loin I intend to test both cuts. To try and reduce animal variation, if possible, I will try to use cuts of meat from the same pig for all of the testing. I will be looking for a sample size of 1Kg (2.2 Lbs) each as, although not big, is a size that may well be commonly cured by our members. These tests will all be performed skin off.
The two brines I intend to use are:
1 US gallon = 3.78 litres
1 Cup of sugar = 240 g
1 Cup of salt = 273 g
1 Tbs Cure#1 = 17 g
Cure#1 = 6.25% Nitrite and 93.75% Salt
|Brine # 1 - Thread brine from "Prague Powder #1"|
|Per 3.5 US Gallon||Per 5 Litres|
|Cure #1||14 oz (397 g)||150.04 g|
|Brown Sugar||2-5/8 cups (630 g)||238.1 g|
|Salt||3/4 Cup (204 g)||77.1 g|
This has a starting Nitrite concentration of 9.38 g per 5 litres = 1,875 mg per litre
|Brine # 2 - Pops Lo-Salt Brine|
|Per US Gallon||Per 5 litres|
|Cure #1||1 Tbs (17 g)||22.49 g|
|Brown Sugar||1/2 Cup (120 g)||158.7 g|
|White Sugar||1/2 Cup (120 g)||158.7 g|
|Salt||1/2 Cup (136.5 g)||180.6 g|
This has a starting Nitrite concentration of 1.41 g per 5 litres = 281 mg per litre
In the various threads on the forum there is also variation in the recommended time that the meat remains in the brine, so I will test each of he cuts of meat in each brines for both 7 and 14 days. Including the control samples this will result in 12 samples being tested:
Sample 1 Uncured sample from Belly Pork to act as a control
Sample 2 Uncured sample from Pork loin to act as a control
Sample 3 Belly pork from Brine #1 after 7 days
Sample 4 Pork loin from Brine #1 after 7 days
Sample 5 Belly pork from Brine #1 after 14 days
Sample 6 Pork loin from Brine #1 after 14 days
Sample 7 Belly pork from Brine #2 after 7 days
Sample 8 Pork loin from Brine #2 after 7 days
Sample 9 Belly pork from Brine #2 after 14 days
Sample 10 Pork loin from Brine #2 after 14 days
Sample 11 Sample of Brine #1 before pork added
Sample 12 Sample of Brine #2 before pork added
I may also test a sample of meat that has been previously frozen to see if that has any effect on cure uptake.
At the beginning, a control sample of each cut of pork will be taken to measure initial Nitrite levels (if any). These will be vac packed and frozen.
Each sample of meat will be weighed before being placed separately in individual containers of brine.
After the allotted time in the brines the samples will be removed, patted dry and weighed.
The sample will then be left in the fridge for 24 hours to equilibrate, patted dry and weighed again before a central cross section sample is cut.
Each sample will then be vac packed and frozen.
At the end of the trial the frozen samples will be delivered by hand to the government licensed laboratory for testing.
The sample preparation and storage methodology above has been pre-approved by the laboratory.
The lab turn around for the testing is 10 working days (2 weeks) and as soon as I receive the results I will publish them in full.
If you have and suggestions or comments on the methodology then please let me know over the next few days before I begin the trial.
This should be fun to do and will hopefully provide the lacking evidence to support, or otherwise, the methods that are being routinely recommended on the forum.
Post updated to reflect the increased salt from Pops brine as requested.
Post updated to use Pops Lo-Salt curing brine as requested
Edited by Wade - 1/29/15 at 6:38am