# Where to place temperature probe in fermentation chamber **URL:** \ **Category:** Systems, Gear, & DIY\ **Created:** [April 27, 2012, 6:35pm UTC](https://forum.homebrewersassociation.org/t/where-to-place-temperature-probe-in-fermentation-chamber/10212 "2012-04-27T18:35:21Z")\ **Posts on this page:** 6\ **Page:** 2
**Author:** ![tag](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/tag/32/10151_2.png) [@tag](https://forum.homebrewersassociation.org/u/tag)\ **Post date:** [May 1, 2012, 3:09am UTC](https://forum.homebrewersassociation.org/t/where-to-place-temperature-probe-in-fermentation-chamber/10212/21 "2012-05-01T03:09:48Z")
I am confused, you have 2 sensors? It is always best to measure the thing you are trying to control. > [@euge](#): > > Well there’s a big difference between “opening a lid” and “opening a door.” It’s not a great idea to keep opening a fermentation chamber with a door- of course all the cold air will spill out. After 12-24 hours I’ll peek in to see if there are signs of fermentation beginning and if I see it I don’t open the chamber for a week- sometime longer. > > My “probe” hangs about halfway down the chamber wall supported by a piece of Styrofoam. I have a thermistor attached to the end of a long thick copper wire inserted into a dry plastic vial. This long wire measures the ambient temp of the chamber next to the fermenter and hangs off the lid of the fermenter in the pic. The fan stirs the air around keeping convection going and blows directly on both probes. > > So far when I measure the temp of the beer with my super-fast Thermapen it matches the temp of the surrounding chamber even at the height of ferment. > > ![2012-04-30%252014.20.43.jpg](https://us1.discourse-cdn.com/brewersassociation/original/1X/e86ec01b320a8f721e991c3efc18fe9be481570f.jpeg) ---
**Author:** ![kylekohlmorgen](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/kylekohlmorgen/32/7926_2.png) [@kylekohlmorgen](https://forum.homebrewersassociation.org/u/kylekohlmorgen)\ **Post date:** [May 1, 2012, 1:18pm UTC](https://forum.homebrewersassociation.org/t/where-to-place-temperature-probe-in-fermentation-chamber/10212/22 "2012-05-01T13:18:57Z")
> [@](#): > > It is always best to measure the thing you are trying to control. +1 - We did studies on fermentation temp profiles in college - it’s surprising how much different a fermenting body of wort can vary in temp from inside to outside and from top to bottom. I do think a plastic bucket allows for more accurate temp reads and more distributed temps when controlling the temp via ambient air temp changes (like a ferm. chamber). > [@](#): > > I am confused, you have 2 sensors? +1 again - what’s the other one for? ---
**Author:** ![euge](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/euge/32/5060_2.png) [@euge](https://forum.homebrewersassociation.org/u/euge)\ **Post date:** [May 1, 2012, 4:20pm UTC](https://forum.homebrewersassociation.org/t/where-to-place-temperature-probe-in-fermentation-chamber/10212/23 "2012-05-01T16:20:34Z")
> [@kylekohlmorgen](#): > > > [@](#): > > > > It is always best to measure the thing you are trying to control. > > +1 - We did studies on fermentation temp profiles in college - it’s surprising how much different a fermenting body of wort can vary in temp from inside to outside and from top to bottom. > > I do think a plastic bucket allows for more accurate temp reads and more distributed temps when controlling the temp via ambient air temp changes (like a ferm. chamber). > > > [@](#): > > > > I am confused, you have 2 sensors? > > +1 again - what’s the other one for? I stated what it was for. And again I measure no difference between the fermenting beer and the surrounding air. My tools are calibrated and accurate. I go by what I observe. ---
**Author:** ![onehoppyguy](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/onehoppyguy/32/5963_2.png) [@onehoppyguy](https://forum.homebrewersassociation.org/u/onehoppyguy)\ **Post date:** [May 1, 2012, 5:04pm UTC](https://forum.homebrewersassociation.org/t/where-to-place-temperature-probe-in-fermentation-chamber/10212/24 "2012-05-01T17:04:59Z")
> [@euge](#): > > > [@kylekohlmorgen](#): > > > > > [@](#): > > > > > > It is always best to measure the thing you are trying to control. > > > > +1 - We did studies on fermentation temp profiles in college - it’s surprising how much different a fermenting body of wort can vary in temp from inside to outside and from top to bottom. > > > > I do think a plastic bucket allows for more accurate temp reads and more distributed temps when controlling the temp via ambient air temp changes (like a ferm. chamber). > > > > > [@](#): > > > > > > I am confused, you have 2 sensors? > > > > +1 again - what’s the other one for? > > I stated what it was for. And again I measure no difference between the fermenting beer and the surrounding air. My tools are calibrated and accurate. I go by what I observe. If you have circulating air in your chamber, that and the internal convection currents will keep the temperature very consistent throughout the beer. ---
**Author:** ![tag](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/tag/32/10151_2.png) [@tag](https://forum.homebrewersassociation.org/u/tag)\ **Post date:** [May 1, 2012, 6:04pm UTC](https://forum.homebrewersassociation.org/t/where-to-place-temperature-probe-in-fermentation-chamber/10212/25 "2012-05-01T18:04:21Z")
> [@euge](#): > > My “probe” hangs about halfway down the chamber wall supported by a piece of Styrofoam. I have a thermistor attached to the end of a long thick copper wire inserted into a dry plastic vial. This long wire measures the ambient temp of the chamber next to the fermenter and hangs off the lid of the fermenter in the pic. The fan stirs the air around keeping convection going and blows directly on both probes. > > So far when I measure the temp of the beer with my super-fast Thermapen it matches the temp of the surrounding chamber even at the height of ferment. Sorry, I was confused.  The probe hangs in the air.  And the Thermistor is closed in a vial.  So the “probe” measures the temperature of the air and the thermistor measures the temperature of the inside of the vial? Fermenting wort produces heat.  Have you ever measured the temperature of the fermenting wort inside the fermenter and compared it with the thermapen’s temperature of the outside of the fermenter? ---
**Author:** ![euge](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/euge/32/5060_2.png) [@euge](https://forum.homebrewersassociation.org/u/euge)\ **Post date:** [May 1, 2012, 6:14pm UTC](https://forum.homebrewersassociation.org/t/where-to-place-temperature-probe-in-fermentation-chamber/10212/26 "2012-05-01T18:14:47Z")
Yes same results. :o [Previous page](https://forum.homebrewersassociation.org/t/where-to-place-temperature-probe-in-fermentation-chamber/10212.md?page=1)