Project “A” 2016 (3) – Testing the Equipment

Fermented Sausages: Testing the Equipment

Includes the following:

  • “Observations on Sausage” by Stan Marianski
  • Ordering Supplies
  • More Wisdom from Chuckwagon
  • “Troubleshooting Humidity Controls” by el Ducko

Don’t neglect to read the Introductory Chapter !
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You can review the posts from the original Project “A” (135+ pages, divided into thirds ) by clicking one of the following:
Wisdom Gleaned from the Original Project “A” (part 1)     (part 2)     (part 3)


Experimental Results: Refrigerated Temperature Control:
Testing out the temperature control is straightforward. Plug the refrigerator “curing chamber” into the In-Line Voltage Switch, dial in the desired temperature on the switch control, make sure that the refrigerator’s built-in temperature setting is low enough that it is always on (so the in-line switch or controller takes precedence), and place a temperature/humidity indicator inside the refrigerator.

There are no contents in the chamber, and thus the thermal inertia is not what it is going to be when loaded with meat. It swings widely, though steadily, two or three degrees F above set point to five degrees below.

Assuming that the curing chamber will “always” be in an environment where cooling will be needed, such as in a Texas garage, this will be adequate for curing meat. However, why not add humidity indication and control capability while you are at it? This is a convenient time.

Experimental Results: Refrigerated Temperature Control
Two sections of tubing run through the rear wall of the chamber. I agonized about this, and made sure that the cooling system would remain intact. Fortunately, for my installation, the compressor and “works” are located in the base, and aluminum refrigerant tubing runs up the back and into the upper left corner, where it feeds the sheathing surrounding an ice tray storage area. I came in through the back, a couple of inches down, low enough to clear everything but high enough to get it well above the plastic floor. (I got lucky here, as will be seen later. Always drill a small hole through the backing material only, then poke around with a paper clip or toothpick to check for refrigerant lines. If you don’t…)

Outside, an aquarium air pump connects to the tubing, and on the inside, a small aquarium “air stone” is on the outlet end. This drops into a half-pint jar, which is left dry for the moment. Running the air pump for several days, the humidity inside the chamber varies in the 30% to 40% range, moving up and down with ambient air humidity.

With water in the jar, humidity rises into the 70% – 80% range, fluctuating with outside air humidity. This is neither high enough nor stable enough. Replacing the air pump with a higher-volume pump had little or no effect on humidity, suggesting that dissolving air in the water is a limiting factor. Replacing the jar with an Erlenmeyer flask, the air stone in the bottom, filled with ¼ inch crushed rock (calcium carbonate, in my case) helped considerably to break up the air bubbles. Humidity ran at a reasonably steady 82% to 86%. Replacing the higher-volume air pump with the smaller pump had no effect. Conceptually, though, the smaller pump is probably better.

More Tinkering:
Ambient conditions won’t always be as warm, nor the air as dry, so it will be necessary to recirculate the air and to vent as necessary. I placed the air pump in a plastic bag and routed the air discharge tubing into the same bag, using a wire twist to secure the opening. Air, humidity, fumes-to-come, and all, recirculate. The anticipated condition is that water will be produced during fermentation, and will have to be vented. A small amount of air can be vented to control the environment inside the chamber. For now, though, moisture should accumulate and drive the humidity upward. With the air pump and bag “reservoir” outside the chamber in the heat, there should be little or no condensation. However, under cool conditions, there will be water plus an accumulation of condensed fumes, noxious compounds, mold and such in the bag. After several days, the bag should puff up a little, because of the additional water vapor and also the fact that water has a lighter molecular weight than nitrogen.

I removed the ice tray door, hoping that circulation might help. Humidity took a nose dive, into the 70% – 75% range, and water began dripping out of the ice tray area. I reinstalled the door, and hung a paper towel down into the refrigerator area a few inches, hoping to correct the problem. Sure enough, humidity was restored, and climbed to the 95% level (top of range for the indicator).

After several days, though, excess water from the paper towel ran down and filled up the bottom of the refrigerated compartment. I wiped this out, folded the paper towel a bit, and routed it into the top of the Erlenmeyer flask so any excess water would flow back into the flask. This time, it worked.

At this stage, two things might be considered: (1) Plug the ice tray with an air bag or bubble wrap, to keep humid air out. This probably won’t work, because water will still condense on the outside of the ice tray shelf, which contains most of the refrigerator’s heat transfer surface. (2) Remove the ice tray door again, Install the circulation fan, and then operate the humidifier control hooked to the air pump. (Use the current paper towel setup until the controller is operational.) With either scheme in place, try bagging the air pump again.

The Controllers Arrive:
About this time, the two controllers that I ordered via Amazon arrived. I went to work, preparing to drill a pilot hole in the back panel so I could “nibble” out a 1-¼” hole for wiring and put in a 1” grommet to cover the jagged edges. I should have drilled a shallow hole first, barely penetrating the covering, then probed inside with a paper clip or wire. As luck would have it, and having thought that I had located all the refrigerant lines, I drilled a quarter inch hole- – directly into a refrigerant line. Suddenly there was a hissing sound, the refrigerator filled with vapor, and oil fogged my safety glasses. I could not have drilled a hole more squarely into the refrigerant line if I had tried.

Moral of the story– – check before you drill. I bought a refrigerant line patch kit for $18, then called around and found that it would cost $200 to purge the system, then vacuum and refill it. My $35 dorm refrigerator was junk.

Two weeks later, I sheepishly bought another $35 refrigerator via Craig’s list. This time, I pushed a hole in the cardboard backing, probed for hidden refrigerant lines and, finding none, cut the hole for the electric sensors and heater power.

The recirculation line idea still was attractive, so I purchased some 1-¼ “ PVC pipe and steeled myself for the process of cutting two more holes in the refrigerator. With the circulation fan installed in a “cross” fitting with two sides capped, I could tap in some control wiring if I wanted, plus some sort of external humidifier instead of the bubbling Erlenmeyer stored inside the compartment. I may still do it. However, faced with a $200 bill for fixing that first refrigerator, I decided to wait. I hope to gather enough nerve to do some more work on this “…Real Soon Now.”

Humidity Control a Simpler Way:
The original idea of controlling humidity was to use a “salt marsh” saturated mixture of potassium chloride and water to fix the humidity at 85%. One way would be to use the recirculation piping (previous paragraph) with a reservoir to contain the salt/water mixture. For that option, it will be necessary to modify the aquarium air pump to discharge makeup air into the recirculation reservoir, yet have all the metal parts (especially the electrical parts) outside the reservoir’s corrosive atmosphere. One way of doing this is to replace the Erlenmeyer flask with a different container, with the air pump’s air movement portion mounted inside. This will be tried later. An external mount would be a good space-saving idea. However, it is necessary to have the water inside the chamber where it can be temperature-controlled.

The “salt marsh” concept was easier. It offers the ability to set the humidity at either 75% or 85% as desired, simply by changing the salt solution. I elected to lock the humidity with potassium chloride. One way would be to do the external circulation variation, pouring enough granulated KCl into the water flask full of rocks to saturate the water, plus some. Do this by pouring out water into a side container, then adding KCl, then when it looks like saturation is passed and you can see granular salt, add more salt and a bit of the saved water back in. However, this requires mounting the air pump inside the chamber. I elected to go with a large tray instead.

Important- – there should always be visible solid salt present. Otherwise, the mixture will not be saturated.

“Dry Run” Testing:
To test, run the equipment for several days to prove that it works as desired. Most likely you will want to improve your air recirculation system by adjusting the fan location and direction. Test first with humidity control not active, and if using salt/water, with it not yet in place. Try the system out at 30 degC, 86 degF, in heating mode and then at 20 degC (68 degF) in cooling mode. (In summer or winter, you may have to wait for one or the other test if you can’t move your equipment. Mine, using a small “bar” refrigerator, is easy to move but at the cost of restricted capacity.)

Then, calibrate your humidity indication/control equipment. Install a tray of pure water, and try various arrangements of internal fan and draped paper towel. Pure water should take the equipment to 99% humidity. Calibrate the humidity controller’s zero to register whatever the humidity indicator that you are using. (It’s probably not that accurate, either, but the zero ought to be pretty good.) When in doubt, adjust the zero so that the instrument reads, say, 98%.

If using salt/water for humidity control, install it now and repeat the tests. This will give you a further check on system accuracy, and you can readjust your zero if not satisfied. This and the pure water test will give you a feel for what to expect from your control system- – how well it maintains normal conditions under no-load conditions (no meat or sausage present), and how quickly it responds to a startup from ambient conditions. Remember, though, that under normal operating conditions, the meat/sausage will be giving off water from the fermentation and from drying, whereas a no-load condition may require water to be added in order to get the humidity high enough.

Using potassium chloride, you should be reading 85% or so, and if using sodium chloride, 75% or so. The absolute reading isn’t important, as long as it’s close to the appropriate one of those two readings. This further calibration is a good “sanity” check. You will want to control your humidity at or above the appropriate reading. …speaking of which, go ahead and enter setpoints into the temperature and humidity controllers.

At startup, after loading the equipment, be sure to keep a record of how well the control system responds to loading with meat/sausage, or to a major upset such as a power upset.

More of My Experiences:
I relocated all of my equipment to a convenient location for longer-term operation (in this case, from Texas to North Carolina). I set up my fermentation/cure box in the garage. I held the various small pieces of equipment loosely in position with coat hanger wire: sensors & wiring, heat source, and internal circulation fan. Coat hanger wire works wonders for “nailing down” stuff that might shift over time, such as the temperature/humidity control sensor tips and the 40 watt soldering iron used as a heater.

In this case, the sensors are just to the left of the cooling coil ice tray shelf, and the soldering iron is inside the shelf where the ice tray used to be. The circulation fan is in there too.

annotated innards
Wiring/Sensors/Heater/Fan Layout

I’m still tinkering with the fan’s position. I aimed it toward the rear of the refrigerator compartment, but at a 45 degree angle for now. There is about an inch gap between the cooling coil ice tray shelf and the rear of the interior. The gap serves to lower the average air velocity in the refrigerated compartment, as does the rather wide shelf shown at the bottom of the photo which takes up about a quarter of the interior. This, plus the size of the refrigeration coil, forces me to use only the front four to six inches of the compartment to hang sausages or meat, so the idea is to direct air out the back, away from the meat/sausages.

20151214_152748The shot at left shows where the curing hanger stick was placed. The position of the saw-tooth brackets is determined by the space between the coiling coil tray and the front of the cabinet. Center it. There are shelving projections on the door liner, but fortunately they won’t interfere with any hanging meats. The saw-tooth supports were chosen so that a small amount of adjustment could be made as needed, and were fixed in place with epoxy cement. Unfortunately, the cement didn’t hold. They were reattached with shirt self-tapping screws.

You’ll need to consider the door when positioning the brackets. If there are molded-in shelves on the door, remove them or, if necessary, trim them so that they don’t get in the way. Any patching will probably be ugly, but needs to be done. In fact, if you must trim, you should probably use spray foam insulation, then a layer of fiberglass/epoxy, to seal the cuts. Otherwise, nasty stuff will grow inside the door. Fortunately, I was able to avoid trimming anything. However, I will have to be careful when positioning the sausages, so as not to hit the door protrusions.

Likewise, with the wires and tubing all installed, seal the rear access opening. (Admittedly, skipping this step for a while is a good idea, as you never know when you’ll need to adjust tubing or wire length.) One option is to foam the outside (which, in my case, is lined with cardboard), then epoxy the cold side of the opening. Bear in mind that food should not be exposed to urethane foam.

Testing the Controls:
The two controllers which I purchased were both from Amazon, a Lerway STC-1000 “110 volt all-purpose temperature controller + sensor 2-relay output thermostat” for $16.79 and an AGPtek WH-8040 digital air humidity controller, 1%-99% RH range HM-40 sensor type” for $25.99. The temperature controller turns on one relay when the temperature is above setpoint plus an adjustable deadband, and another relay when the temperature is below setpoint.

The humidity controller, as it comes, turns on a relay when the humidity drops below setpoint. Its output mode can be reversed so as to turn the relay on when above the setpoint. This is easily changed. (Go ahead and do so, as humidity will be at or above setpoint under all operating conditions except when the door has been opened.) Change this so as to turn on an air pump if humidity gets too high. For now, though, I plan to count on the “salt marsh” and door opening method to control humidity.

The two halves of the split-range temperature controls were tested separately, then together, under no-load conditions (no salt/water tray or meat present). The refrigerator test was run at 20 degC, and cycled about 5 degrees below setpoint. It was a warm day, but heat input from the garage surroundings wasn’t very high. The heater test was run at 30 degC, and cycled 6 or 8 degrees high.

The combined heating & cooling control works well on heat cycle, +1/-3 degrees around a ½ degree deadband, without a tray of salt/water. This was as expected- – during part of the cooling cycle, the heater was cooling down but still warm, and during part of the heating cycle, the refrigeration system still contained cold Freon. The cycle was smaller than the two individual portions, reflecting better control at the expense of efficiency.

Adding the mass of the tray and salt mixture slows response quite a bit. I use “lite” salt (potassium chloride, KCl) from the grocery store, which hold 85% humidity instead of sodium chloride’s 75%. It’s non-toxic, which is always good. By running at 85% humidity, maybe we can avoid some of the previous “Project A” guys’ case-hardening issues at 75%.

In my equipment, I added 17 oz of KCl “lite Salt” to a food-grade (400-series) stainless steel or plastic tray and poured a cup of warm water onto it. That’s about 2 grams KCl per gram water. It got cold! That’s ionic interaction going on, one of the interesting things that happens when KCl grabs onto water molecules. This reduces the tendency for liquid water to escape to the vapor phase (lowers the vapor pressure of water by weakly binding with it), which causes the humidity in the air over the mixture to be “locked in” at a lower amount than would be experienced with pure water only. (I would later change out this pan for a rectangular plastic one, the size of the refrigeration coils, that will catch any water drips. The problem with this oval one was that drips missed, unless caught and redirected with a paper towel. …not a long term solution, plus it exposes pure water to the air, rather than salt water.)20151215_154142

Home improvement stores like Lowe’s sell potassium chloride in bulk. My local Lowe’s carries 40-pound bags of “Sodium Shield” potassium chloride for $29 USD per bag. One bag would probably be a lifetime supply for each and every person involved in this project. The stuff doesn’t go bad- – at the end of any given run, you take the pan into your kitchen, put it into a 185 degree or so oven, and leave it all day. At the end of the day, the water has evaporated out, whatever meat vapors have condensed into the tray have been cooked, and you are left with crusty, slightly yellow potassium chloride. Break it up and pour it into a container with a lid, so you won’t spill it, and it can be reused. …so don’t bother buying a forty pound bag. Buy what you need at your local grocery store for five bucks or so.

To test with the tray in place, I put it into the chamber below the heating/cooling items and let it run overnight, allowing the equipment to come to a stable state. Practically speaking, the equipment stabilizes at some operating state near equilibrium, moving in response to various disturbances but not moving away significantly. Equilibrium is a myth, of course, because there’s always a disturbance and an “inertial” resistance to the response to it, but equilibrium can be approached. The more we can do to help it, such as moving air over the surface of the liquid to improve contact and mass transfer, the closer we can get.

In this case, the humidity moved up and down a few percent, oscillating with the temperature, which was cycling up and down about three degF. However, it was offset about ten percent low, mid 70’s. I tried folding a paper towel and clipping one end onto the ice tray shelf, dipping the other end into the salt water, to try to increase evaporation. I also changed the aim of the fan. In this way, I was able to get the humidity up from about 75% to around 77 percent.

The humidity indicator, my “check” device, read higher, so I replaced the salt/water pan with one of pure water, rigged up a paper towel wick, and aimed the fan to blow across the surface of the pan, toward the paper towel.

Next day, there was a lot of free water in the compartment, the check humidity indicator read 99%, and the humidity controller read in the high 80’s. I adjusted the zero upward about 9 degrees, then removed the pure water, wiped up the free water, and reinstalled the KCl salt pan. I also changed the leveling screws so the chamber would tilt toward the front, making it easier to wipe out free water in the future. The humidity indicator immediately dropped into the 80’s. The slower-responding humidity check indicator started down. Overnight, the two indicators approached each other. I re-zeroed the indicator, adding in a couple of percent (total of 11 percent offset) and it registered near 85%, the expected value for a KCl “salt marsh.”

Observations on Sausage by Stan Marianski.
This would be a good time to review some observations made by Stan Marianski. On page 104 of his book, “The Art Of Making Fermented Sausages”, Stan lists several interesting facts:
• The length of the sausage has no influence on drying time.
• Sausages should be dried at a rate not higher than the moisture losing ability of the sausage.
• Traditionally made sausage have pH of about 5.3 and Aw about 0.88 at the end of the drying process.
• The drying chamber should not be overloaded as a uniform air draft is needed for proper drying and mold prevention.
• The higher the air speed, the faster the drying.
• Larger pores in certain type casings facilitate faster drying
• The more fat there is in a sausage, the faster it will dry.
• The larger the meat particle size, the faster it will dry.
• The larger the diameter of a sausage, the slower it will dry.
• A fully loaded chamber will dry slower as air movement is restricted.
• Molds will develop more quickly if there is no air draft at all.
• Excessive drying hardens the surface and closes the casing pores.
• If the casing becomes greasy, wipe it off with a warm cloth, otherwise it may inhibit drying.

Time to Order Supplies:
We’ll be making two sausages in fairly rapid succession: the “Summer Sausage” recipe will tie up your newly-tested equipment for three or four days. Assuming you need to make a modification or two… maybe a few days longer. Then, we’ll start the main topic: Salami d’Allessandra” will tie up your equipment for two to three months.

So while you’re testing, go ahead and order the supplies for both recipes. You should have them within a week, if you live in the USA. Have a look at the following recipes for what you’ll need.
• Summer Sausage, Cervelat or Goteborg
• Salami di Allessandra

More Wisdom from Chuckwagon: Posted: Fri Jun 17, 2011 09:21
Before we actually start grinding and mixing meat, there are a few more items to consider:

1. Distilled water – All the chemicals used to treat your town’s water supply, can really raise hello with the bacteria we need in Bactoferm. You can purchase distilled water, but home crafters like us can easily make our own. See how at this link:

2. We should go into section 3 (Cultures) and read a little about Bactoferm and what it does. It’s at this link:
It’s not complicated, nor is it lengthy. I realize there’s been a lot of reading lately, but these are things you should have tucked away in your sausage savvy. I look at it this way: For centuries, man had no idea what was happening inside salami and certainly had no concept of fermentation due to lactobacilli. I’m just happy to be living in a time where we have the technology to understand such “saddlebum science” and craft better products because of it. We don’t have to memorize the names of the microorganisms or even learn how to pronounce them, but we should have a little knowledge concerning them so we’ll know what is happening inside the curing chamber. Let’s take advantage of the great information Stan Marianski has so generously provided (at no cost).

3. We should be finishing up the details on our fermenting chambers. Let’s test run them before we begin. For this particular recipe, we will not be using the heaters in your new fermenting cabinets. Later on, making a fast-fermented sausage, you may need to heat the chamber as high as 115˚ F.

4. Soon, we should read section 4 so we don’t end up poisoning ourselves. It is called “Safety Hurdles” and is at this link: […]

Best Wishes,



Troubleshooting Humidity Control: 3/27/16

…anybody else out there having problems controlling humidity in their fermenting/curing chamber? Here’s what I have run into, and some speculation on what to do about it. (Note that I haven’t completely fixed it either, and continue to fight the problem.)

Be sure to check your equipment at both 20 degC and 12 degC, temperatures needed for Project “A”.

  • Problem: water dripping from cooling coils into chamber. Symptom: water on floor of chamber.
    1. Solution: obtain a square pan large enough to catch all drips. Use it for the salt/water mixture (“salt marsh”).
    2. Possible other solution: form an aluminum drip catcher to channel drips back into the “salt marsh” pan.
  • Problem: Humidity consistently 10% (or so) low. Symptoms: Humidity spikes upward when door is opened, then goes back to same consistently low reading.
    1. Has the water/salt pan gone dry? Check it. Look for puddles of water and, if there, solve as above.
    2. Possible low air circulation within curing chamber, over salt/water pan. Solutions:
      1. Relocate or re-aim circulation fan. Blow directly on salt pan contents if possible.
      2. Install or adjust aluminum foil baffle(s) to direct air flow over water/salt pan, but try to avoid hitting the sausages.
  • Problem: Low (15% low or more) humidity indication, varying with time and ambient conditions. Humidity spikes upward when door is opened, then goes back to too-low reading. Primary symptom: abnormally low humidity reading.
    1. Symptom: Has the water/salt pan gone dry? Check it. Look for puddles of water and, if there, solve as above.
    2. Additional symptom: Ice forming on cooling coils.
      1. Solution: Redirect air onto cooling coils plus, experiment with aluminum baffles, to eliminate ice. (see above for ideas)
      2. Solution: It may be that you are trying to operate at too high a humidity level for your system. (Example: 12 deg C, 85% humidity, system can’t cope.) If recipe allows, either reduce humidity (say, to 75% with different salt), or increase temperature slightly.
      3. Solution: If system can’t cope because heater is too big, try a smaller heat source to reduce temperature swing (cool portion of cycle may be overcompensating).
      4. Solution: If system can’t cope because heater is too small, try a larger heat source to increase temperature swing (heat portion of cycle may be unable to compensate.
      5. As an alternate to both heater solutions, try “base-loading” heat input with an adjustable but constant amount from a “trim” heater.
    3. Additional Symptom: NO ice forming on cooling coils.
      1. Solution: You may be on the verge of forming ice, but not quite there. Try the “ice forming” solutions above.
      2. Try adding a small but constant flow of outside air.

Unlikely causes:

  • Too much water. (If there is plenty of salt in the water/salt pan, it will simply condense into the salt/water pan and remain there, dissolving a bit more salt.)

ADDENDUM: 4/19/16 Over a period of about two months, the aluminum foil baffles corrode, get brittle, and start to fall apart. I am experimenting with dishwashing scrub pads as an alternate. I have placed one in the space between the “salt marsh” and the freezer coils, to keep the air circulation off the sausages hanging on that side of the chamber. I continue to tinker. Decent stability continues to be a challenge, hopefully due to there being no load (no wet sausages) present. Humidity swings from 70+ % to 85% as temperature changes. I’ll blame that on slow evaporation, for now, but continue to tinker with baffling in order to boost it. Maybe I should add a small aquarium water pump and spray attachment?

FURTHER ADDENDUM: Mounting the fan to the side seems to solve the problem. Humidity rises to where it should be, and only varies about 5% over a “salt marsh.” Additional advantage: salt encrusting of the fan (and consequent fan motor failure) is eliminated for the most part.

Adding an air bubbler seemed to help. Adding four bubblers threw too much salt water into the air, depositing salt on practically everything. …not recommended, although having one bubbler seems to help.

The best solution, however, seems to be mounting the fan high and to the side, blowing downward. The following shows the configuration during a test, “pure water only,” using a small ultrasonic “fog machine” to supply vapor. …cool-looking, if nothing else, but it seems to work and eliminates the need for salt.

Fan Relocated to Side of Refrigeration Coil


Ultrasonic Fog Machine






Onward to Next Chapter

13 thoughts on “Project “A” 2016 (3) – Testing the Equipment

  1. Duk, Marilyn figures a trip to HIll Country is a reward so she’s packing a bag whilst I stay home and bury my face in the classifieds.

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