The Science of Salting

[indaswamp]

Great Primer!

The Science of Salting

In salami, salt absorption simply happens when you mix all the salt and seasonings into the ground meat and fat. The surface area of the ground meat is high enough that the salt will quickly and easily be absorbed. No special conditions or even further mentions are needed for successfully salting salami.


In whole muscles, salt absorption and distribution may require several weeks, but the process is simple, reliable, and hands-off. Salt absorption and dispersal will take a couple of days for a thin slice of loin, a couple of weeks for a coppa, but might take 2 months for a large bone-in ham.


The key to salting meat is the process of diffusion. If you remember your high school biology, the concept behind diffusion is the tendency for substances to disperse through a substance until an even concentration, or equilibrium, is reached. For example, if you dissolve salt into a glass of water, you won’t find pockets of saltier water in the glass—the concentration of salt is equal throughout. The same concept can be applied to meat—given enough moisture in the meat for the salt to dissolve, the salt will disperse to create an even concentration throughout the meat. (As a side note to those who remember diffusion and osmosis always being taught together, osmosis is also involved in this process, but osmosis is a type of diffusion, and specifically involves movement across a semi-permeable membrane.)


The process looks like this:


First, salt is applied to the outside of the meat and begins dissolving into the layer of moisture coating the meat. The dissolved salt starts to migrate from the area of high concentration (the salty outside of the meat) to the area of low concentration (the interior).


At the same time, the water inside the meat (a high concentration of water) starts migrating to the salty layer on the outside (a low concentration of water). This results in moisture leaving the meat. Not enough moisture is lost for any significant drying of the meat.


What then follows is a back-and-forth of salt and water. Salt goes in, water goes out, but as the salt concentration increases inside the meat, the water “follows” the salt back in, and everything keeps moving around, slowly reaching equilibrium.


If you’re salting a piece of meat in a plastic bag, and one day you notice lots of liquid in the bag, then return a few days later to find it relatively dry, it’s because the water was reabsorbed by the meat as the interior became more salty.


If you’re salting the meat on a rack, as opposed to in a bag, the exuded liquid cannot be reabsorbed, so you have less moisture remaining in the meat at the end of the process, and the drying process may be a little quicker. You’ll see this in the recipe for dry-cured hams.


As the salt is being absorbed, it’s important to keep the meat cold to limit bacterial growth. Keep the salted meat under 40 degrees F, and if it’s in a sealed bag, you don’t need to worry about humidity, but if it’s open in the low-humidity environment of your fridge, it may start to dry out, which will limit the ability for the salt to move freely—I suggest covering the container that holds the meat with plastic wrap.


It’s impossible for me to tell you exactly how long this process will take, but if you use a precise weight of salt, there is no threat of oversalting, so I’ll usually leave meat for 3 weeks (ham is the exception, and it’s detailed in its own section).


Note


Cure #1 contains standard table salt (NaCl) and sodium nitrite (NaNO2 ), while Cure #2 is salt (NaCl), sodium nitrite (NaNO2 ), and sodium nitrate (NaNO3 ).

Salting and Preservation

To explain why salt is important for the preservation of meat, first understand that bacteria require water to survive and reproduce; stopping bacteria by removing their access to water is the primary preservation technique of dry-curing. Along with a series of other effects, salting meat will reduce the water available to bacteria, but salt does not actually dry the meat.


To clarify, as the salt dissolves and diffuses through the meat, the salt molecules bind with the water molecules, which makes the water unavailable to bacteria, but without actually removing the water from the meat. A raw, unsalted piece of meat is a damp and ideal environment for bacteria, while a raw, salty piece of meat is still a damp place, but has significantly less water available for bacteria, allowing for short-term preservation as the meat is then dried.


The amount of available water in a piece of meat is more accurately described as “water activity,” abbreviated as Aw. Commercial producers closely monitor Aw using digital water activity meters, but observing the weight loss of a drying piece of meat is adequate for the home producer.


It’s important to note that the amount of salt used in dry-curing lowers the water activity enough to provide short-term preservation of the meat, and provides a window of time to dry the meat, but it is not enough salt for long-term preservation. In order to lower Aw enough for long-term preservation, you need to either remove water by drying the meat, or reduce the water activity by heavily salting the meat, like a piece of salt cod or salt-packed anchovies. By employing the drying process in conjunction with salt, you can achieve the long-term preservation of meat without salting beyond palatability.

The Basics of Salting

 

[SmokinEdge]

This is some great information.

 

[chopsaw]

That's interesting and good info .
I just had something unexpected happen to me with an eye round of beef .
Pre-seasoned , vac'd and in the freezer for 7 months or so . Thawed it out and smoked it a last week .
I don't know if it " cured " is the right word , but sure seemed like it to me .

 

[motocrash]

That's interesting and good info .
I just had something unexpected happen to me with an eye round of beef .

Agreed.
I wasn't expecting a "ham chop" after being in brine for 20 hours.

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[indaswamp]

That's interesting and good info .
I just had something unexpected happen to me with an eye round of beef .
Pre-seasoned , vac'd and in the freezer for 7 months or so . Thawed it out and smoked it a last week .
I don't know if it " cured " is the right word , but sure seemed like it to me .

Thanks Chopsaw.
I'd say the beef most definitely did cure. The temperature gradient as meat freezes will accelerate the movement of both salt and fluid around within the meat...both as it freezes and thaws.

 

[lathrop]

My last pork shoulder came out under salted. So I am wondering what proportion of salt most people use in their rubs. Previous pork shoulder have been good but I am always looking to improve.

 

[chopsaw]

I'd say the beef most definitely did cure. The temperature gradient as meat freezes will accelerate the movement of both salt and fluid around within the meat...both as it freezes and thaws.

I figured this is on topic , but wanted to make sure before I added pics .
I used Canadian steak seasoning I get at Gordon's food service . I do this so I can go straight into the SV . Wanted sandwiches so I thawed it . Thawed in the bag , there was no juice in the bag as it thawed . Took it out and overnight in the fridge to dry before smoking . Next morning I could smell " cured " but didn't think anything of it . Always some thing in there that smells that way .
I smoked it to an internal of 120 . Then when I make a sandwich , I slice and pour warm beef broth over them to warm up , and further cook .
There was no juice come out of this , even when Sliced . It was some of the most tender and juicy eye round I've had . I was talking to Sam zwiller about this and I think he made a good point . Outside of the salt maybe there is another seasoning in the mix that has natural nitrites in it .
Again this was pulled at 120 internal . You can see the color . I need to revisit this and smoke to a higher temp to see if it comes out like dried beef .

 

[indaswamp]

Interesting Chopsaw. While this thread was aimed more towards how salt applies to both Salumi and salami and the safety involved for those uncooked products, it is also applicable to hams.

I agree, there must be some nitrites to achieve that pink color.

 

[SmokinEdge]

What kind of salt did you use chopsaw ?
I ask because people always like to point to Parma ham as being “cured” with just salt, and it is,,, sea salt from a specific region of the Mediterranean Sea, and that salt contains natural nitrates.

 

[chopsaw]

What kind of salt did you use

It's Canadian steak seasoning from GFS . Trade East is the brand . Don't know what salt is in it . Coarse salt , pepper , dried onion and " spices " Sam made mention of maybe celery powder . Salt would have an effect . It might have been frozen for a year . I'm not sure .

 

[indaswamp]

Good thinkin SmokinEdge and Chopsaw....both are possibilities.

 

[zwiller]

Busy gents... Wasn't talking celery powder but herbs in a seasoning or rub. Some have nitrates. I think it might be dill from a paper I read but lost the link. SmokinEdge I have not looked into it but is this web or book info about Parma Harms? No idea tha was the case but am a german ham guy.

 

[MikeD79]

My last pork shoulder came out under salted. So I am wondering what proportion of salt most people use in their rubs. Previous pork shoulder have been good but I am always looking to improve.

I am new to pork shoulder, but my recent attempt turned out great with the salt ratio I used from other pork rubs I’ve done in the past. I use the salt in other seasonings that make up my rub plus add my own cherry wood smoked coarse ground kosher salt. In total the salt makes up around 1/3 cup out of approximately 2 cups total seasoning. It really turns out to be a preference however and I do know people who like to go much heavier on the salt than I do.