[flbrewer]

Although I have the probe taped to the fermenter and covered w. bubble tape, I am getting the following...

Kicks on at 66.2 degrees, runs for 2 minutes or so and kicks off once it drops below 65. It will go down to 63 or so and slowly start to raise again. It takes about 25 minutes for it to kick back on.

Obviously this isn't the water temp inside my fermenter that is floating around this much. I'm ok with that as long as the water temp remains somewhat constant. Is this normal for a chest freezer setup like this to have to run this often?

[euge]

Temperature-wise you have something that is static (water) while the beer will be dynamic during the attenuation phase. It will behave a bit differently I think.

Depending on he season and what's happening inside the freezer could kick on fairly often which is still ok. Your controller should have some short cycle avoidance feature.

Test runs are cool but the real test will be a fermentation run.

[flbrewer]

I'm wondering if just measuring air temp would be easier and assume (or test) for the difference between the beer and the air. IMO, after 72 hours or so the beer is very stable in temp. I could plan on a lower setting during the first few days.

[euge]

It's what I do.

[flbrewer]

A guy over at Reddit responded that you should use sand...interesting stuff, transcript below.

"I worked in a research lab and in a commercial lab in my previous job and the standard was to put the temp sensor in a jar surrounded by sand. Taping to the wall will give you artificial high and low readings. Submerging in water will give you possibly an idea of what the brew temp is but many times chest freezers over shoot and end up over cooling due to the fact that it takes a while to cool water down.
For best results use a probe in a plastic wrap surrounded by sand"

[JT]

That's great if you were fermenting sand. 

[JT]

I'm wondering if just measuring air temp would be easier and assume (or test) for the difference between the beer and the air. IMO, after 72 hours or so the beer is very stable in temp. I could plan on a lower setting during the first few days.

I actually use a dual controller and a single controller.  Here's why:
If my target is 67 degrees, the dual controller will kick the freezer on when the beer hits 68 and shut it off as soon as the beer hits 67.  The problem is the freezer ambient could be 40 degrees at that point and the beer will keep plummeting causing the fermwrap to kick on and get the beer back up to 67, which soon turns to 68 and the process starts all over.  My dual controller probe is either taped to the carboy or in a thermowell. 
Enter the second controller.  This single Johnson controller is plugged in between my freezer and dual Ranco.  The probe is measuring freezer interior ambient temp.  It is set to turn the freezer off if the temp drops to 60.  This keeps the freezer interior from ever getting too cool.  It will turn the freeze cycle off prior to my beer moving from 68 back to 67, but the cool ambient temp always brings it down. 
Complicated?  Yes.  But complicated?  Yes.

[euge]

Unnecessarily so most likely.

ffbrewer why not just brew a batch and see what it does?

[flbrewer]

Unnecessarily so most likely.

ffbrewer why not just brew a batch and see what it does?

This weekend!

[Hickory]

I just used mine for the first time yesterday and had an oops moment. My nice warm faucet water couldn't get my beer down under 80 so I put it in the chest freezer and set it for 65. Came back from dinner and it was down to 60, even though my diff was 2*, and the sanitizer in my airlock was completely frozen. Thank goodness I hadn't pitched my yeast yet. So I unplugged it and let it come back up to 65 naturally and then pitched my yeast. All seems to be going better now, 24 hours later, but it was a stressful few hours.

[waltsmalt]

I use an old Ace bandage from a knee scope with some paper towel to insulate the probe.  No tape goo and reusable.  The Ace bandage has Velcro on it.

[klickitat jim]

I use an old Ace bandage from a knee scope with some paper towel to insulate the probe.  No tape goo and reusable.  The Ace bandage has Velcro on it.

Brilliant! Im going to grab a roll of the sticky rubberized elastic wrap. Blue of course

[JT]

Unnecessarily so most likely.

ffbrewer why not just brew a batch and see what it does?

Forgot to add that I noticed improved tasting results after eliminating those beer temp swings during fermentation (just going by my own tasting - no panel or blind tests). It also cut way down on cycling.  YMMV

[narcout]

If my target is 67 degrees, the dual controller will kick the freezer on when the beer hits 68 and shut it off as soon as the beer hits 67.

Which dual stage controller are you using?  I am in the market.

Came back from dinner and it was down to 60, even though my diff was 2*, and the sanitizer in my airlock was completely frozen.

If you fill your airlock with vodka instead of sanitizer, you can eliminate the freezing issue. 

[JT]

If my target is 67 degrees, the dual controller will kick the freezer on when the beer hits 68 and shut it off as soon as the beer hits 67.

Which dual stage controller are you using?  I am in the market.

Came back from dinner and it was down to 60, even though my diff was 2*, and the sanitizer in my airlock was completely frozen.

If you fill your airlock with vodka instead of sanitizer, you can eliminate the freezing issue.

I'm using the Ranco.  It was about the only option I found at the time, although there are others now I think.