How many on/off cycles per hour is harmful to my fermenting freezer?

[eddiek85]

I've got an STC-1000 hooked up to my chest freezer fermenting beer at 16c with the 'd' setting at 1 degree so that it kicks on if it reaches 17c. Currently it is turning the compressor on about every 20 minutes for 5 minutes or so.

I was just wondering how often is too often for the compressor to turn on before it starts becoming harmful for the freezer?

While we're on topic I was also wondering about the knob on the side of the freezer that has numbers 1-10 and controls the freezer 'strength'. Does it matter if I have this set to the lowest setting or highest? I currently have it at 5, but thought perhaps having it on the lowest setting would aid the freezer in gradually reaching temp rather than putting it on full blast and bringing it to temp quickly.

Any advice would be greatly appreciate!

 

[MaryB]

The temp setting shouldn't matter but I turn mine to max cold. It cycles LESS as a fermenting fridge than it will as a freezer so no harm there at all.

 

[Owly055]

The only real issue is starting under load. Refrigerators and freezers can cycle a lot, but there should be a delay of a few minutes between cycles to allow the internal pressures to equalize. Thermostats for these units are designed to provide that delay. The STC1000 has a delay function F3, which allows a delay to be programmed of from 1 to 10 minutes. It defaults to 3 minutes, which is pretty safe.

The reality is that you have a large quantity of liquid which is inherently very temperature stable. That means that your temperature range in the chamber can vary over quite a wide range from the high to the low without having any effect on the brew temp to speak of, as long as the average is the temp you are looking for. Air has a very low thermal mass, while beer has a very high thermal mass....... Being extreme as far as precise temp control within the fermentation chamber is pointless and will have no effect.

H.W.

 

[logdrum]

I set my F3 to 10 min with max cool, plus tape the (insulated) sensor to the side of the fermenter. Once I've reached equilibrium , the freezer rarely cycles

 

[eddiek85]

I haven't set the delay setting, but I have the 'd' set to 1 degree so the temperature goes to 16 and then turns off the fridge, then takes about 20 minutes to climb up to 17 degrees which is when it will kick the fridge on again. So in that case, is the delay necessary still? Sorry if the question seems to answer itself but I'm just trying to make sure I do it right lol.

Thanks for the replies all!

 

[logdrum]

Are you measuring ambient air temp or is the probe affixed to your fermenter?

 

[kristiismean]

You should not have it set up to measure the air temp,

it should either be attached to your fermenter, or if using it as a kegerator, dipped in a bottle of water/alcohol, etc.

 

[JONNYROTTEN]

You should not have it set up to measure the air temp,

it should either be attached to your fermenter, or if using it as a kegerator, dipped in a bottle of water/alcohol, etc.

This is not 100% accurate.
I only measure liquid temps while fermenting. For large temp swings like a cold crash or D rest the probe measures air temp. If you measure liquid temps for large temp swings its takes hours (like 12 or more) for the liquid to adjust and the freezer will run continuously the entire time freezing the freezer to a block of ice. Leave the probe in the for cold crashing, Drest or any temp swing over a few degrees...

 

[JONNYROTTEN]

I haven't set the delay setting, but I have the 'd' set to 1 degree so the temperature goes to 16 and then turns off the fridge, then takes about 20 minutes to climb up to 17 degrees which is when it will kick the fridge on again. So in that case, is the delay necessary still? Sorry if the question seems to answer itself but I'm just trying to make sure I do it right lol.

Thanks for the replies all!

Leave the temp setting at one degree so your beer ferments at the exact temp you want it. Set the differential for 10 minutes. The beer doesn't care about a 10 deg lag time one bit.
I've had mine set this way for years