STC 1000 CONTROLLER: How to set it to keep fridge safe?

[jcbogantes]

How to set the STC-1000 to keep fridge safe?
I'm brewing an APA, to use my new controller. But I have hear some stories of burned out compressors with controlers like the STC 1000.

I was thinking to set it like this:
F1: 19 C
F2: Differential at +/- 1 C
F3: 8 min

Is that OK, or should I leave the factory settings as I have seen some videos on the web?

Thank u in advance,

 

[doug293cz]

How to set the STC-1000 to keep fridge safe?
I'm brewing an APA, to use my new controller. But I have hear some stories of burned out compressors with controlers like the STC 1000.

I was thinking to set it like this:
F1: 19 C
F2: Differential at +/- 1 C
F3: 8 min

Is that OK, or should I leave the factory settings as I have seen some videos on the web?

Thank u in advance,

Set F3 to 10 min (the max)

Brew on

 

[d3track]

Probe placement is more important, imho. Leaving it dangle in the air will allow for more temp swings.

 

[doug293cz]

You can adjust both differential and thermal mass around the probe to adjust cycle time. Larger differentials and more thermal mass will both give you longer cycle times (you should still set the compressor delay to the max.) In a fermentation chamber, you want the temp probe to be coupled to the beer in the fermenter. This can be done by placing the probe in a thermowell in the fermentation vessel, or you can tape the probe (covered with a little insulation) to the side of the fermentation vessel. Taping the probe to the side of the fermenter has been found to give more stable beer temperature due to better response time (and being partially coupled to the chamber temperature.) In a keggerator/keezer, placing the temp probe in a container of water works well, as you don't have to worry about heat being generated by fermentation.

If you are using a dual action controller (like the STC-1000) and have a heater in the chamber, you want to use the smallest wattage heater that will maintain the target temps when the air outside the chamber is the coldest it will get. Using a higher wattage heater will heat the chamber rapidly when turned on, which can often cause excessive temperature overshoot, requiring cooling to be turned on sooner and more often (the system oscillates, rather than stabilizing at the setpoint.)

Brew on

 

[cannman]

I have my F3 set at 3 min... but I have found that my freezers (Kenmore Commercial) have an automatic restart guard. You also want to set your ferm temp right in the middle of your yeast's threshold and allow for the freezer to swing within the allowable temp values with F2. IE, if I had a yeast that wanted to ferm at between 10c-20c, I would set my F1 at 15c, F2 at 4c, and F3 at... 3 for the maximum life of your freezer. I run certain strains tighter... I'm not comfortable with a 10 min rest on F3, A lot can happen in 10 minutes... sometimes I forget to close the lid because I get a phone call or some distraction happens. If i'm checking the beer at noon, this might be an ester disaster!

FUN!

 

[AnthonyUK]

The STC-1000 is fine running at 1.0°c accuracy. No need for such a large swing range in a fridge at least. Just set the compressor delay to 10 mins as mentioned. Mine has been running in this way for 5+ years.

 

[jcbogantes]

Thank you for the answers.

About thermal mass: I'm detecting a difference of 2 -3 C degrees, when I attacht a thermometer with foam and tape outside a milk jug compared to the probe of the STC-1000 in a sandwish bag and inside the milk jug with water. So

I think I am gonna keep it inside the milk jug. I am just thinking that might be even closer to the thermal mass of the fermenting bucket.
Do you agree on this?

 

[Gavin C]

I set mine like so.

Hysteresis +/- 0.3C (the minimum)

Delay 10 mins (the maximum)

Same settings for my fermentation chamber and kegerator/keezer.

Fermentation chamber probe set like so. Insulated from ambient and monitoring beer temperature (exothermic fermentation needs direct monitoring).


Keezer, probe is in a 4 oz jar of baking soda at the bottom of the keezer.

 

[Rcbandl]

I personally would keep it attached to the fermenting bucket itself, with something to insulate it from the ambient temperature. I fold a rag, put it in a zip lock and use a bungee cord to hold it to the side of the carboy. Then slide the probe in. You will get a better reading of the actual temperature of the fermenting beer since the fermentation will slightly raise the temp.

 

[doug293cz]

Thank you for the answers.

About thermal mass: I'm detecting a difference of 2 -3 C degrees, when I attacht a thermometer with foam and tape outside a milk jug compared to the probe of the STC-1000 in a sandwish bag and inside the milk jug with water. So

I think I am gonna keep it inside the milk jug. I am just thinking that might be even closer to the thermal mass of the fermenting bucket.
Do you agree on this?

Nope, don't agree. Fermentation is an exothermic process (meaning the yeast give off heat while working.) Thus the beer in the fermenter will often be 4˚ - 5˚F warmer than the chamber temp, and as much as 8˚ - 10˚F warmer for some very active yeasts. You want to control based on the beer temp, and the consensus best way to do that is with the probe fixed to the side of the fermenter with insulation between the probe and the ambient. A thermowell also works to monitor beer temp, but can lead to wider thermal excursions when using a simple on-off controller. There is a solid theoretical explanation for this, as well as experimental evidence that supports it. There are ways to control even better by using algorithmic controllers (like the BrewPi), but they require multiple thermal probes.

Your temperature differential test has a couple of issues:

• You are using two different temperature probe + electronic units, and you don't report having calibrated them against each other. The temp difference you see could be due simply to calibration differences.
• Your test jugs are at different levels in the chamber. Vertical temperature stratification in common in refrigerators, and this could also account for the temperature difference you are seeing.

Brew on

 

[Gavin C]

+1

100% correct. Listen to @doug293cz before he gets math at you

 

[jcbogantes]

Thanks doug293cz, you are right on those details. I'm going to set the whole experiment again and re-test before getting to the real deal.

 

[AnthonyUK]

Nope, don't agree. Fermentation is an exothermic process (meaning the yeast give off heat while working.

Totally agree. I have logged the temperature of the wort with the probe attached to the FV and in another container of liquid and this was my findings also.