Dry ice to cool brine/cure solution

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Smoking Guru
Original poster
OTBS Member
SMF Premier Member
Jan 4, 2014
Montague County, TX
Hey folks, need to get scientific here...

We have a new member to the group H hickorysmokes and he sadly suffered what many of us have before, and that's having to toss a creation that he cured. In this situation it was a ham that he was wet curing and it looks like it suffered from "bone sour" and an incomplete cure. One of the things that he mentioned was using dry ice to bring the brine temperature back down below 50 degrees.

I am NOT looking to question his process as much as I am wondering how dry ice, and the generation of CO2, could effect not only the meat, but the reaction of the CO2 and the curing agents and salt.

Here is what he posted

I did not inject the curing solution.

I also had trouble regulating the temperature of the cooler and the brine temperature rose the the upper fifties about day four before I brought it back down with dry ice.

I'm a science guy, but not sure of the introduction of CO2 into the mix here. I have some ideas, but before I inject my opinions, I want to hear from others.

Again, NOT wanting to critique his methods, I'm looking for information about how the CO2 could possibly interact with the meat and the wet brine/cure ingredients REGARDLESS of temperatures.

Yes, I've done the googlefu, most of what I got was all about how meat producers raise the CO2 levels and are killing the Earth...

Let the OPINIONS begin...
CO2 is food safe. It’s in a lot of things, I see no issues with it especially in the center of his ham. His ham failed because he didn’t inject, simple as that.
CO2 is food safe. It’s in a lot of things, I see no issues with it especially in the center of his ham. His ham failed because he didn’t inject, simple as that.

I, and he agrees, the question Im asking is HOW/DOES/IF CO2 reacts with nitrites, nitrates, and sodium.
It's been a long time since I've studied inorganic chemistry, but CO2 in water forms carbonic acid, which lowers the pH. Practically speaking, there is always some amount of CO2 in water, so I doubt the dry ice would lower the pH below maybe 5.5 or so...not strongly acidic.

But carbonic acid reacts with sodium nitrate for form sodium carbonate and nitric acid. https://tutata.me/reactions/12041 Nitric acid reacts with sodium nitrite to form nitrogen dioxide, a gas. So I see a pathway for dry ice to break down sodium nitrate and sodium nitrite.

Couple of caveats: I've no idea what the kinetics of these reactions might be. They could be pretty slow in cold water. I'm also not sure if the relative concentrations of the reactants are high enough to drive the reactions forward at a reasonable rate. So that might have been what happened, but I'm far from certain.
I adjusted the reaction to sodium nitrite and carbonic acid and it produced sodium carbonate and nitrous acid. Been 45 years since college chemistry and they weren't involving food safety. Carbonic acid also does not form in large volumes of water.
Now if carbon monoxide (CO) was introduced that would definitely screw up the process. CO reacts with myoglobin much the same as nitric oxide (NO) and would probably result in incomplete cure.

Side note: CO was used in the food industry to extend the nice pink color in meat and to extend the shelf life of seafood.

I saw 4 failures in original thread
1. not enough cure time
2. not injecting in a thick piece of meat such as a pork leg.
3. temperature way out of safe zone (exceeded 40°F)
4. following advice from a writer that followed advice from another writer that gives sketchy recipes.

What if it's served with green eggs? :emoji_sunglasses:
Only see that in over done hard boiled eggs.
How about eggs that were harvested about 10 days late? I need to get a photo of that next time it happens. We often buy "farm fresh eggs" and once in awhile there isn't a fresh one in the carton.
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CO2 is a non reactive gas, it’s what you are expelling from your lungs as you read this post.

No, CO2 is a really reactive gas that forms carbonic acid when dissolved in water, and likes to play in all sorts of organic reactions otherwise.
I’d vote that if you want to use it it to chill your brine, you should put it in an open ziploc bag and shake it frequently to dislodge the brine ice from surface of the bag.
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