How to Make a Dry Curing Chamber

When doing research into dry curing, I soon realized how precious little there is on the subject. The dry curing method I am referring to is the hanging of sausages filled with choice meats, salt, dextrose (or sugar), fresh spices and sodium nitrite and sodium nitrate (Insta Cure #2) in a controlled environment with relatively low temperatures and high humidity. Ideally, this is done where the climate permits, which is why Italy has for so long produced the best dry cured (salumi) products, and for the same reason San Francisco has become the unofficial U.S. capital of Italian salumi. Some of the traditional dry cured meats include sopressata, capicola, prosciutto, pepperoni and the leader of the pack, salami. Being in Buffalo, NY this would have been perfect to do in the winter months, but we tend to crave salami even in the summer. Most people live in climates and environments that do not have ideal temperatures and humidity for prolonged periods of time. So, we have to create them. Once the controlled space has been created, it won’t matter where you live or what season it is. You can have dry cured pepperoni, salami, capicola… you name it. That was one of the main reasons for making this curing chamber: It will take the climate in your location virtually out of the equation by letting you create your own micro-climate.

The parts list shows each product used individually, its estimated cost, whether or not we carry the item, our recommendation for its use and why the product is needed in the first place. 

First, we need something that will provide hanging space and keep a cold temperature. What better than a refrigerator? People are always selling their old fridges - open up the local classifieds or Craigslist and you’ll find one in no time. A quick peek through and I found at least 5 in and near my hometown with prices ranging from $50-300. I would go for a middle-of-the-road, maybe $150 one. The majority of refrigerators sold are “frost-free,” which will not be a problem because the automatic defrosting will be countered by the humidifier and the humidity controller. The fridge we have has the freezer in the bottom portion, which also turned out to be a major plus in the construction of our chamber. Refrigerators that have the freezer on the left or right side of the fridge provide less room for hanging large diameter salami or prosciutto, so I would recommend the models with the freezer under the fridge portion. I would also strongly recommend you purchase a refrigerator with a "ground" (it should have a three-prong plug).

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First thing: We gutted the fridge of all its loose shelves and lockers. Even if it appeared clean, we used an antibacterial cleaner with bleach. Try to get into the corners too, since the conditions for "bad" mold growth will be introduced into this relatively small space and we want the good mold to form on our products’ casings and not some potentially dangerous foreign mold. 

At this point we tested the refrigerator without the temperature controller to see what the lowest (warmest) setting is and ours was around 38°F, which is too cold. We plugged the fridge into the temperature controller and set the temperature to 46°F. The fridge turned on once the temperature rose 2° above 46°F. The cooling compressor kicked into gear and the temperature started to steadily drop. When it got to the set temperature it turned off again. The cycle continues for as long as the batteries are working or the unit is plugged in. And without fail, the temperature stayed close to the temperature we set it to. The controller has a cooler and heater setting, as well as a °C or °F setting, and wide vs. narrow temperature variance setting (read instructions thoroughly). 

The first invasive procedure: We have to be able to hang meat from something. A couple options come to mind. We can do it large smokehouse style, drill in some shelving brackets on the side walls and when ready, hang the salami off of the resting wooden (or metal) dowels. Another option is strategically putting screw hooks into the ceiling of the fridge then hanging the products off the hooks. Problems here would be the hooks' permanence and more likelihood of the product pulling the hooks out (make sure the threading on the hooks is thick). But, if done right, I think the screw hooks could be satisfactory. We decided on the brackets. Whatever you use, secure it well. With the amount of relative humidity and length of time per usage, you will want to use stainless steel screws, brackets, hooks, etc. or ABS plastics. 

Next we are going to cut out a large opening in the fridge/freezer divider. This will provide us with more usable space. This section will be the new home of our humidifier. The side walls and door typically contain nothing more than insulation, but be very careful not to damage the cooling system (it may have wiring, who knows. Unplug entire unit before digging around). When buying a used refrigerator, there is little hope that the seller will still have the manual or siagrams that it may have come with originally. Ours didn't. The refrigerator we have has a light fixture in the precarious portion of the feezer where we want to cut a large hole, so this is what we did. Find the model number of the unit - ours was "596.69142991" and we found it on a plate/label on the ceiling of the fridge in plain view (pictures 3 & 4). The manufacturer's name is also on the label. Jot it down, locate it from the list on appliance411.com and when you enter the respective model's site, there should be a model # search. Our fridge is a Kenmore, so we went to searspartsdirect.com, entered the model #, a little navigating and we got exploded schematics of the inner workings of our unit (the parts, components, location of wiring, etc.). Some models may not be as lucky, but it's not a major problem if you remember (if you plan on doing any cutting) to do it with surgical gentleness, patience and care. You may not want to do any expanding of the area in your refrigerator. That's perfectly fine, actually even better; why bother fixing something that's not broken. If this is the case, skip the whole procedure. All you basically need are the items in the parts list but even so, read through the rest of the tutorial for additional tips on dry curing.

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With the schematic diagram we now know where these wires are going and where to be especially careful when cutting (picture 5). We simply used a box cutter to cut the plastic and a large knife for the insulation. As mentioned earlier, the interior of the walls will be almost entirely insulation, so when cutting, it will get everywhere (pictures 5 & 6). The wiring diagram showed us where the wiring is, but it didn't say at what depth they are so when I was cutting the plastic surface with the box cutter, of course, I sliced 2 wires that lie just beneath the surface. No problems. I needed to splice and elongate the wires anyway so that I can hide them along the sides before covering the exposed areas. All I used was insulated wire, butt connectors, crimper and electrical tape. The insulation will also now be exposed around the cut out area. This can be covered with plastic wrap, hot-glueing plastic (ABS) strips over it, forming stainless steel over and screwing it in. You can use any food-safe materials to simply cover the exposed area. We have a lot of scrap metals in our shop so I used stainless steel, made them into large C brackets, locked them tightly into place with stainless steel screws and filled in the cracks with food-grade silicone sealant. If using this method (stainless steel), make a channel in the insulation (away from the metal), tuck the wiring into the channel and seal the wires with foam insulation to prevent accidental contact with the metal. Once held in place in the insulation, use liquid foam insulation to permanently keep the wiring away from the metal. The hole we cut was large enough to allow free flow of mist out of our humidifier into the chamber.

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The aging/curing/fermenting chamber is completed. In both pictures above, the temperature controller is located on the top-left outside wall. It came with a bracket for installation. The controller will keep the internal temperature steady. The humidifier will produce moisture to the levels we need (more accurately with the humidity controller) The picture on the right shows a different humidity controller than is available through the Sausage Maker, but both do the same thing. Distilled water is highly recommended for the humidifier as it doesn't have calcium and metals, plus it is easier on the filter and humidifier in general. I cut a notch in the refrigerator's gasket for the thick cables (cords) to pass through without breaking the door's seal. The thin wires from the probes are simply pushed against the door's gasket when closed; moisture escaping through the tiny space it creates is insignificant. The HygroThermometer is on top of the unit, held in place with two simple homemade L brackets. The chamber is ready for use.

Use this tutorial loosely. If you don't have a bottom cooler, don't sweat it - just purchase a smaller humidifier or use food-grade sodium acetate or put inch-thick table salt on a wide tray with enough water to just saturate the salt or pipe in the moisture from outside the refrigerator. The humidity in this sort of chamber (using the humidifier) is not constant. It typically will rise quickly and then slowly (15 minutes or so) drop to the point before the humidity controller turns it on again. You could see fluctuations in the 10 to even 15% range. That may seem pretty extreme, but the humidity will mostly stay around its set level and for most recipes it will work just fine. Anyway, the humidity controller helped a lot in keeping the humidity close enough to what we wanted and is a great product.

Now that the unit is complete, it is time for the "dry run." Test your chamber thoroughly and document the results without any meat. What range is the temperature inside experiencing? How about the humidity? Keep good records of the testing because they very well may come in handy later on. There may have to be tweaks along the way and it likely will not be perfect. But what we want is not perfection; we want a dry curing chamber that gets the job done. So once you are satisfied with the dry runs, it's time to get it started with an actual recipe. You will notice that many dry curing recipes demand a warm and moist environment (incubation) for a couple hours or even days before they are put in a cool one. The temperatures in those recipes are unlikely to reach beyond 90°F, so a hot plate may be overkill. What we did for our recipe was put two 75W incandescent light bulbs inside (not too close to the walls) and plugged them into the temperature controller which we set to heat, and then set our high temperature. The bulbs were connected to outdoor weatherproof lampholders to protect from exposure to the humidity. We strongly recommend you use weatherproof holders and/or bulbs. Now that you have a chamber of your own, start with a less demanding recipe such as pepperoni before going into something like a large-diameter salami. The very long, 6+ month recipes for products like prosciutto or capicola may be difficult to duplicate with this relatively small unit. DO NOT TRY such demanding projects before becoming completely knowledgeable and experienced on the subject of dry curing.

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For anyone who wants to start a hobby of dry curing or even has a beginner's knowledge of the subject, we STRONGLY recommend reading a complete yet understandable book on the subject. The Sausage Maker has recently made available a book that covers the subject's intricacies with language that doesn't discourage the beginner nor oversimplifies the complexities involved. Ladies and gentlemen, we present to you the newest Sausage Maker favorite: The Art of Making Fermented Sausages by Stanley and Adam Marianski. Hope this tutorial was helpful, or at least got you going in the right direction!

-Sausage Maker Mac