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 the high humidity. I tried many ways to fix it, but nothing 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 how 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. I 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 the changes in the ambient humidity that affected 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. The 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 a 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, the 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 than 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 more precise temperature control.
This controller also controls the Optimus Cool Mist Ultrasonic Humidifier in my setup. Later, I 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. I took two pictures as the numbers on the controller 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 the 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.
Updates on results, new mods and new observations
Update 1 - 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 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 2 - 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. The diffusion rate is the rate at which moisture inside the sausage travels toward the surface. The 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 humidity can lead to inferior results, not just slower drying.
Update 3 - August 4, 2016
Auber is now shipping a new version of the temperature and humidity controller, TH220 that looks like this:
It has the same high RH sensor and can control either heating or cooling and either humidifying or dehumidifying. I like it more in black, looks more stylish.
Update 4 - April 17, 2020
I've long suspected that my controllers may not be accurate. Professional calibration is inconvenient and expensive, while the salt method is not reliable enough to instill confidence. I've generally been happy with my salumi, but am I getting the best results I can? Though, I check my meats periodically and adjust humidity up or down depending on how the skin feels anyway. It's never been a 'set it and forget it' process. I've also experienced a few puzzling situations where I had no idea how they could possibly happen. So, I decided to invest in a professionally calibrated reference hygrometer. My choice landed on Hanna Thermohygrometer HI9565, which I purchased from their website. I've had a couple of Hanna PH meters for many years, and they've been exceptionally accurate and reliable. I hope the hygrometer shows the same level of accuracy and longevity. So far, I've been delighted with it. It has a 0 -100% range (very few of them do), high accuracy (±2.5 %), and is quite responsive. Was it worth it? Absolutely! Here is why:
Update 5 - April 17, 2020
I've been asked dozens of times about Inkbird vs Auber controllers. Are Auber controllers better? A while ago, I bought Inkbird ITC-308 and Inkbird IHC-200 temperature and humidity controllers with the intention to play with them and do a detailed review, but life had other plans for me. At some point, I used them with one small batch and they did the job. Then, while I was testing my Auber controllers against the Hanna HI9565, I decided to throw the Inkbirds into the mix. How did they do?
Out of the box, both Auber and Inkbird RH deviated from the reference Hanna hygrometer by 9.5 percentage points (Inkbird) and 3.7-4.3 (Auber). This was when measuring RH in the fridge at 56F, after a 30-minute stabilization period.
When testing outside of the fridge at room (basement) temperature of 68F, again after a 30-minute stabilization period, Inkbird was off by only 3.2 percentage points, while Auber was off by 6.7.
Here is another test under the same conditions as before, but Auber had a brand new sensor. Again, the Inkbird was the closest, off by only 3.4 units, while Auber was off by 7.2. Note how the temperature reported by Inkbird is spot on, while Auber is off by almost 2 degrees.
Auber controllers seem to be optimized for the curing temperatures of around 55F, while Inkbird seems to be more accurate at higher temps and vice versa. Both Auber and Inkbird humidity controllers are not perfect and need to be calibrated. The deviations that they show are significant enough to cause major impact on curing results.
If you calibrated them at 55F, will they still be accurate at 70F-80F during fermentation? This is where a reference hygrometer like Hanna becomes invaluable.
Update 6 - April 18, 2020
I've received quite a few emails over the past year asking me if I were still continuing with my curing and what my curing chamber looks like now. I am very much so! I never really stopped, but there were some breaks here and there. My meat curing chamber hasn't changed much, with the exception of adding a heating source and the Hanna hygrometer that I mentioned above. The heat source is a 10" x 20" seedling heating mat.
I started off with a 20" x 48" one, but it was very bulky. When I tried the smallest one, it worked quite well too. I tested a ceramic heat lamp as well but was not comfortable with it; it gets too hot, requires special mounting and, above all, had no advantages over the seedling heating mat. A picture is worth a thousand words, so here is how my current setup looks:
Update 7 - April 18, 2020
A short while ago, Auber released two new controllers, Auber HD220-W humidity controller and Auber TD120-W temperature controller. Both are Wi-Fi enabled, while the HD220-W is programmable with up to 8 stages where you can specify humidity and duration. This opens up new possibilities (see update #8). I've been playing with both over the past few weeks and I like them. My plan is to build a separate fermentation/drying chamber which will be equipped with these controllers.
Inkbird has an equivalent WiFi ITC-308 temperature controller, which is not programmable. They also have the ITC-310T model which is programmable but not WiFi enabled. Their humidity controllers, sadly, are not programmable or come with WiFi capability.
Update 8 - April 19, 2020
Check my new preferred curing method, which starts with a week of intensive multi-stage drying, followed by maturing at high humidity levels. It greatly reduces the risk of case hardening, results in more even drying and improves the flavor. Examples:
- Homemade Capicola
- Bergamo Salami
- Salame Toscano (Tuscan Salami)
- Finocchiona – Tuscan Fennel Salami
- Calabrese Salami
- Soppressata Bresciana
Update 9 - January 10, 2022
I've had people ask me about my fermentation/drying schedule that you can see in my recent charcuterie posts. I've shared some details in my most recent post - Salami Sticks. You can use this method with a regular controller but I have to say, Auber HD220-W humidity controller made things easier and more predictable for me. The quality of my salami is much, much better and all I worry about now is various recipes not how to control damn humidity. Speaking of which, lately I rarely use my humidifier anymore, mostly it's the dehumidifier.