Ike
nOob for life
- Joined
- Jan 9, 2015
- Messages
- 532
- Reaction score
- 186
Riddle me this, Batman:
I'm starting my second batch in my fridge-based ferm chamber. Like most "average Joes" on this site, I usually monitor fermentation temperature with a probe pressed against the side of the fermenter and held in place with some insulation and tape and/or bungee cords. I have the probe for the Johnson Controller submerged in a bottle full of water inside the fridge.
Just for grins, and because I'm a former engineer and the only thing better than data is MORE DATA, I spent a few bucks on a thermowell. My thought was to see how much warmer the wort was at the center of the vessel compared to the outside. The thermowell is a SS tube passed through the cap on the glass carboy, filled with water to give the best heat transfer between the probe and the TW.
Well, it is a bit early since we're only about 12 hours into fermentation, but I have steady blowoff tube activity (it's bopping away like an 80's rock band drummer) but my thermowell temps are LOWER than my side temps. WTH? This is the opposite of what I was expecting.
I swapped out the probes, thinking it was a hardware problem, but the situation still holds: the side of the vessel is reading 67 degrees, the thermowell is reading 64.
My only thought: the thermowell is well into the wort, but the shorter length of my probe (story of my life, dude) means it probably isn't below the level of the wort. I'm counting on the water in the thermowell to communicate the heat to the probe. It's possible I'm also sampling the temperature of the gas in the carboy. BUT, given that it is in closest contact with the wort and insulated by the glass carboy, I would guess the temperature of the gas would be similar (although admittedly not exactly the same) as the wort.
Any input? Is this normal? Something like the yeast migrate to the outside of the vessel, making it warmer than the middle? Have I managed to build a ferm chamber that invalidates the laws of thermodynamics? Notify Dr. Who!
I'm starting my second batch in my fridge-based ferm chamber. Like most "average Joes" on this site, I usually monitor fermentation temperature with a probe pressed against the side of the fermenter and held in place with some insulation and tape and/or bungee cords. I have the probe for the Johnson Controller submerged in a bottle full of water inside the fridge.
Just for grins, and because I'm a former engineer and the only thing better than data is MORE DATA, I spent a few bucks on a thermowell. My thought was to see how much warmer the wort was at the center of the vessel compared to the outside. The thermowell is a SS tube passed through the cap on the glass carboy, filled with water to give the best heat transfer between the probe and the TW.
Well, it is a bit early since we're only about 12 hours into fermentation, but I have steady blowoff tube activity (it's bopping away like an 80's rock band drummer) but my thermowell temps are LOWER than my side temps. WTH? This is the opposite of what I was expecting.
I swapped out the probes, thinking it was a hardware problem, but the situation still holds: the side of the vessel is reading 67 degrees, the thermowell is reading 64.
My only thought: the thermowell is well into the wort, but the shorter length of my probe (story of my life, dude) means it probably isn't below the level of the wort. I'm counting on the water in the thermowell to communicate the heat to the probe. It's possible I'm also sampling the temperature of the gas in the carboy. BUT, given that it is in closest contact with the wort and insulated by the glass carboy, I would guess the temperature of the gas would be similar (although admittedly not exactly the same) as the wort.
Any input? Is this normal? Something like the yeast migrate to the outside of the vessel, making it warmer than the middle? Have I managed to build a ferm chamber that invalidates the laws of thermodynamics? Notify Dr. Who!