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MtnDon
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# Posted: 24 Jan 2015 19:43
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I like slow cookers, or to use the trademarked name, Crock Pots. There is one thing that has irked me for a long time. Even on the low heat setting they run too hot for my likes. To my mind low should give a simmer; fluid in the pot should not boil. Virtually all slow cookers do this much of the time because they do not have a thermostat that turns the heater element off and on. The two or three heat settings simply vary the power of the element. The element stays powered 100% of the time. I say virtually all slow cookers because I did find two that do have temperature controls with a thermostat. However, they are high priced and 6 or 6 1/2 quart sizes. That's two big for two people. Hidden in the fine print in some of the slow cooker instructions it is noted that the cooker should never be used less than half full. Nor fuller than 3/4. That 1/2 full minimum explains some of the overcooking when trying to do smaller dinners in a large pot.
As a result of all that our slow cookers have not been used as much as we might like. That has now changed though! 
Take one Chinese made temperature controller off ebay... <$15 There are literaly dozens of sellers. Some direct from China, some from US, some only in degrees Celsius and some in degrees Fahrenheit.
http://www.ebay.com/itm/120-110VAC-Fahrenheit-All-Purpose-Temperature-Controller-Rela y-10ft-Sensor-Cable-/281435311101
Add one aluminum project box, <$14 ...
http://www.ebay.com/itm/250597864242?ru=http%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_f rom%3DR40%26_sacat%3D0%26_nkw%3D250597864242%26_rdc%3D1
Mix in a power outlet, a 2.5 MM jack and plug, a power cord and plug and voila!
We've used it three times so far now, and are happy with the performance.
The tip of the probe is not likely waterproof as it comes. I used heat shrink tubing to help with that. I do have some stainless steel tubing that I plan on using to form a tight fitting jacket for the probe. An alternate would be to buy a probe that is already waterproofed. Ebay has some listed. Probes for some digital meat and smoker thermometers can also be used.
Inside view...
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old243
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# Posted: 24 Jan 2015 22:12
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Don does your probe sit directly in the product being cooked, or in the dry area between the outside of cooker and the cooking pot? old243
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MtnDon
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# Posted: 25 Jan 2015 00:51 - Edited by: MtnDon
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Inside the pot itself with the food. You could elect to have the probe in the liquid or if there was a large piece of meat in the meat itself. We've opted for placing the probe in the liquid portion.So far we've done stew, chili and a pot roast.
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MtnDon
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# Posted: 25 Jan 2015 10:02 - Edited by: MtnDon
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I should have mentioned that the controller can be used in either a heat or a cool mode. Also some vendors sell it in a 12 volt version. That could be used to turn cooling fans on and off at a programmed temperature. Maybe place the probe in the upper spaces of a loft / cathedral ceiling to control an air circulation fan, for example. The built in relay can handle up to 10 amps. Any higher loads would need a higher rated SSR (solid state relay) of the correct capacity.
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SandyR
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# Posted: 25 Jan 2015 17:22
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Can you use the crockpot half full like they suggest and freeze what you don't use? You will have another meal for another time then and won't need to cook. ( FYI potatoes don't freeze well )
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Don_P
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# Posted: 25 Jan 2015 20:27
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One thing I enjoy with forums is the random collision of ideas. Soo... I was just reading an article in this month's "Growing for Market" about hot water seed treatment. It is more effective for many pathogens than treated seeds (usually a fungicide) and the chemical used is hot water. Much like giving the seeds a fever to kill bacteria and viruses, particularly more effective if it isn't something on the surface alone. Anyway they were using a pair of hot water baths about the size of crock pots, the first warms the seeds to 100*F. The second water bath, depending on the seed, runs from 115 to 127*f for a period ranging from 15-65 min. Temperature control and time has to be very tight, the setup they were using runs about ~$1500. Do you think your setup is a possibility?
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MtnDon
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# Posted: 25 Jan 2015 23:51
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It's worth looking at. My initial temperature control tests were done with 2 quarts of water in the 4 quart pot and then a short test with 3.5 quarts of water. I started out at 120 F. I then advanced to 145 F and 170 F. Our pot has a Low and a High setting. I tried both in my tests.
I compared the digital read out to a lab grade dial thermometer. The two provided the same readings; to within a half degree or less. The controller has a range from -58 F to 230 F according to the spec sheet. To confuse things a little some of the published info has slightly different values given. To me the important thing was that the controller and my lab thermometers all agreed within a small margin of error, a fractional degree.
In the tests with the heat selector set on high the temperature would continue to rise to the next degree after the heater element had been shut off. Example: With the controller set to 145 F the temperature rose to 146 after the element cut off at 145 F. The temperature slowly dropped until the digital read out reached 143 and the element was turned back on. The temperature would rise until the controller clicked off. When the element was set to low heat sometimes the temperature would not rise above the 145 F cut off, but maybe a third of the time it would tick over to 146. At temperatures above 99 the readout does not display decimals so there must be some rounding up/down but I have no idea what the algorithm is.
The unit displayed the same pattern at the other temperatures tested.
So, it may be worth a shot for a seed test. My tests were done with a prototype setup that was much less elegant than the item displayed above. I had the bare bones controller, a hacked up extension cord, wire nuts held together with some rubber bands scavenged from asparagus bundles.
I have parts for a second unit as one of these is being gifted to our son. Too bad you are more than half the width of the country away.
I'm not surprised that the specific machine used for seeds is so expensive. There is a cooking process called sous vide, that cooks food sealed in vacuum bags in a water bath at temperatures between 135 and 145 F. Those also cost over a grand+.
Further notes on this controller. The d or delta value on this is adjustable from 1 to 25. That d is the number of degrees between the unit shutting off and then turning back on. I used a value of 1.
A similar controller, but sold through regular electronics channels sells fro $80 and up. There is a more accurate PID controller also available. The PID can take rates of change into account and more closely maintain the set temperature. There are also Chinese low cost and the other higher priced versions.
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MtnDon
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# Posted: 25 Jan 2015 23:57
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SandyR, yes we have sometimes frozen leftovers for use another day. That works, although the texture of many things is altered. My gripe is still that there is almost always a burned on crisp ring of gravy, sauce, whatever liquid around the crock pot interior at the tide mark.
We have newly acquired 2.5 and 1.5 qt crock pots that are better for smaller portions, more suitable for 1 and 2 people. Our son will likely end up with the 1.5 qt.
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