I have been curing meats at home for almost two years. My initial results were encouraging but then it all went downhill. The biggest problem was high humidity. I tried many ways to fix it but nothing really worked. About 4-5 months ago I made another change to my meat curing chamber. This change finally helped me start getting consistent and predictable results. I am now in charcuterie heaven! My curing frustrations are officially over.
Building a meat curing chamber
Building a meat curing chamber at home is ridiculously simple and will not break the bank. All you need is the three things listed below.
- A full size frost-free fridge ($60-$100 on Craigslist).
- A temperature/humidity controller ($50-$100).
- An ultrasonic humidifier ($30-$50).
That is if all planets line up perfectly or you happen to live in an area that is conducive to meat curing. Otherwise you are going to face challenges controlling high humidity.
My first meat curing chamber was exactly like I described above. I also added a digital Extech 445715 Hygro-Thermometer for easy monitoring of internal temperature and humidity. The controller I picked was the analogue C.A.P AIR-2 temperature/humidity controller.
This particular controller controls temperature and a de-humidifier. Wish I had known that before I purchased it. Luckily, I was able to find instructions on the Internet on how to quickly re-wire it to control a humidifier. My first batch of meats turned out fantastic, I could not be happier. No store-bought salami would come even close. Michael Ruhlman’s sopressata was the star.
My meat curing chamber challenges
The next batch I made a few months later didn’t fair so well. My salamis would keep developing some sticky grey coating on them which impacted drying and resulted in spoilage. Wiping off that sticky mess with water and vinegar solution would only work for a couple of days. Then it was back again. I figured I must have done something wrong and made another batch. It turned out not too bad, but not nearly as good as the first one.
Then I realized what the problem was. It was changes in the ambient humidity that effected the humidity inside the meat curing chamber. When the ambient humidity is right the internal humidity in the fridge stays in the desired range and I get perfect results. If not, I would get junk.
Around that time my very old fridge died. I was able to replace it with a practically new one that I picked up for $110 on Craigslist. Same problems continued and I was pulling my hair out figuring out how to bring humidity under control. Specifically, I needed to be able to bring the humidity down. Low humidity was not a problem as I could use a humidifier to take care of that.
The Internet is full of information and misinformation. Sometimes the information is correct, but does not necessarily apply to your conditions. As a result, you take someone’s advice but it does not work for you. You probably have been through that many times. I followed various recommendations. I also tried controlling the meat curing chamber humidity with wet salt. That did not work at all.
Then I made a big tray of sodium acetate which I read about in Stanley Marianski’s book. This method worked fine, but only for a few days. The acetate would quickly get moist and I would need to dehydrate it in the oven. It proved to be too much hassle. I now understand that these methods work well when you have low humidity. When the humidity is high these methods are ineffective. You’ll never know for sure unless you try yourself.
Later I stumbled upon Marianski’s recommendation to use an exhaust fan to get humidity out of the fridge. There are two ways to implement this solution.
- Set up the humidity controller to run the fan when humidity rises above a certain threshold.
- Add a timer to activate the fan at predetermined time.
I cut two 4″ holes in my new fridge, one at the bottom to take air in and one at the top to get the humid air out.
This worked for a short period of time. The humidity would still be fairly high when I would add new sausages, but would come down a few days later. Unfortunately, two months later this system started to struggle. Humidity would not get below 85% and the fan would be running almost all of the time. A couple of weeks later I noticed that when the fan would start running the humidity in the meat curing chamber would increase. What the heck?
During that time ambient temperature got noticeably higher. When warmer air with the same or higher relative humidity is introduced into the cooler fridge it causes internal RH to increase. That’s exactly what happened to me. So, this solution works when the ambient temperature is low or ambient RH is much lower that the one in the fridge. Otherwise you will be getting the exact opposite effect.
Now, some have been saying that 85% RH is perfectly fine for curing meats. I can tell you that it’s not what my experience has been. Sticky goo and nasty molds would attack my meats at high RH. I also noticed quite a bit of case hardening. That was surprising as you are more likely to get case hardening at low RH. I kept looking for other methods. Some are using ceramic heater lamps which is discussed here. This method can be dangerous and, frankly, does not make much sense to me. Why would you want to heat the fridge to make it circulate more often? I also noticed that as soon as the fridge stops running, the RH would shoot back up within 20 seconds. Somehow the moisture needs to be removed. That seemed like a more practical solution for lowering RH inside the curing chamber.
The solution that worked
This all led me to look into installing a dehumidifier into the meat curing chamber. I thought that maybe that would be the solution. Any small size dehumidifiers I was able to find were using Peltier technology. I’ve seen numerous posts on various forums stating that these types of dehumidifiers don’t work at curing chamber temperatures. Darn!
Luckily, one person on Reddit forums reported using one of these dehumidifiers with great results. I took the plunge and bought the Eva-dry Edv-1100 Dehumidifier and I am glad I did. It works, and it works exceptionally well.
This is a smaller version than the one that the poster from Reddit has, but it works just as well from my experience. Another benefit from the dehumidifier is that it provides some air movement when it’s on.
I replaced my less than stellar analogue controller with the Auber TH210 Temperature and Humidity Controller for a more precise temperature control.
Update on August 4, 2016
Auber is now shipping a new version of the temperature and humidity controller, TH220 that looks like this:
It’s has the same high RH sensor and can control either heating or cooling and either humidifying or dehumidifying. I definitely like it more in black, looks more stylish.
This controller also controls the Optimus Cool Mist Ultrasonic Humidifier in my setup. I later added another one to control the Eva-dry dehumidifier. I also have an exhaust fan plugged in but it never comes on as I realized I don’t need it.
Here is another image to show temperatures as the ones above flickered when I took the shot.
There are slight differences in the temperatures and RH reported between the two. I think it’s the result of sensor placement and air movement. I can especially notice the difference when the fridge is circulating and cold air is blowing inside the fridge. When there is no air movement inside the fridge they have almost identical readings.
The way this setup works is one controller is set up to start the humidifier when RH drops below 72%. Because of a small lag the RH drops to about 70% before the humidifier is able to start bringing it back up. Still, this is sufficiently fast.
You may have noticed that I moved the humidifier outside the fridge in the new setup. The reason behind this is that it’s easier to control humidity in larger spaces. The humidifier is pretty bulky and takes a lot of space so it made sense to move it out.
The other controller controls the dehumidifier and kicks in when humidity goes above 78%. Again, due to a lag the RH briefly goes up to about 80-81% before it is brought back down below 78%. The average is about 75% RH, which is exactly where I want it to be. I can tighten the range down to a 1/10th of a degree but that’s not necessary. I don’t want the humidifier and dehumidifier to start competing with each other in a vicious cycle.
Like I said, charcuterie heaven.
The results and new observations
Update on October 29, 2015
A new batch of sopressata just finished drying in my upgraded meat curing chamber. I took some pictures of the final product for those who might be interested. I put it in on October 3, 2015. Now, 26 days later, the sausage has lost 30% of the weight and is ready for consumption. 30-35% weight loss is ideal for this type of sausage. I plan to keep a few sausages a little longer to get to 35% weight loss as I like it a little drier. My kids love softer sausage.
I must say I am very happy with the results. This is one of my best batches, if not the best. It was fairly easy to control the humidity and keep it where I wanted it to be. One thing I did differently for this batch is to gradually reduce humidity over time. I started with 88% in the first 5 days, then dropped it to 83% during the next 5 days The remainder of the drying time the RH was at 78%. This method was described by Stanley Marianski in one of his books.
I don’t have any scientific evidence to show if this method is superior to the one where you use constant humidity from day one. My subjective opinion is that this last batch came out a little better. One thing that jumps out at me is the more uniform firmness of the meat from the center to the edge. It also appears as though the casing is coming off a little more easily.
There meat close to the casing appears to be a bit darker than toward the center. This bothered me a little as usually this is a sign of case hardening. I am fairly certain that this is not the case though.
Common sense tells me that there is no case hardening if the following is true.
- The meat is firm throughout.
- There is no mushiness in the center.
- The casing is soft and peels right off nicely.
I don’t think it’s something to worry about, though it kept me me wondering for a bit.
I did some research and looked through dozens of images of artisan salamis online. Guess what, practically all of them exhibit the same type of dark ring near the surface.
Update November 14, 2015
I let some of the sopressata to dry longer until it lost 35% of the weight. The difference between 30% and 35% weight loss is quite remarkable – it’s firmer, has richer colors and more intense flavors. Everyone in the family agreed that it tasted better now than it did a couple of weeks ago.
The mold is snow-white and no sign of bad molds anywhere.
Shortly after the sausages reached 30% weight loss I noticed that the casings started to feel slightly harder than before. Not by much, but enough for me to feel some increased hardness. I bumped the target for the dehumidifier to 80% and 78% for the humidifier. That did the trick and the casings went back to normal for the remainder of the drying process.
Speaking about case hardening, I found a picture of finocchiona salami I made last spring. It was made before adding the dehumidifier. This salami is a good example of what type of challenges I had to deal with before. The mold on the outside was fine, but inside the meat was pale and very soft toward the center. The salami was edible but not enjoyable. I ended up throwing it out as I had no confidence that it was 100% safe to eat.
If you take a close look at the casing around the perimeter of the cut you will notice a great deal of casing separation. The surface under the casing was quite oily. No wonder it did not dry well. The casing felt quite hard too, despite high humidity. Go figure.
I think what happened is at some point the humidity inside the chamber became too high for efficient moisture removal from the surface of the salami. This affected moisture removal from the inside of the sausage, making diffusion rate > evaporation rate. Diffusion rate is the rate at which moisture inside the sausage travels toward the surface. Evaporation rate is the rate at which moisture is removed from the surface of the sausage. In other words higher humidity means slower drying. Too high of humidity can lead to very poor results, not just slower drying.
Helpful Relevant Resources
This article was updated on January 25, 2019