Ss Brewing Technologies Giveaway!

Home Brew Forums > Home Brewing Beer > DIY Projects > Poll: Fermentation chamber temperature probe placement
View Poll Results: Where do you place your probe?
Hanging in the air 78 23.15%
Insulated against the fermenter wall 157 46.59%
Submerged in a separate container of water 51 15.13%
Inside the fermenter utilizing a thermowell 51 15.13%
Voters: 337. You may not vote on this poll

Reply
 
LinkBack Thread Tools
Old 07-10-2010, 03:02 AM   #21
Catt22
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2009
Posts: 4,998
Liked 57 Times on 55 Posts
Likes Given: 51

Default

Quote:
Originally Posted by RDWHAHB View Post
With all due respect, only if you do it wrong. Use a properly tuned PID to take care of overshoot/inertia problems in your cooling loop.
Yes, obviously it would if one were using a PID controller. No one that I know uses a PID controller on their fermentation chamber fridges or freezers. Most home brewers I know use a Johnson, Ranco or Love non-PID type thermostats. IMO, a PID for this type of application would be major overkill. A simple totally dumb digital or analog switched thermostat works just fine for me.
__________________
Catt22 is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 03:07 AM   #22
Catt22
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2009
Posts: 4,998
Liked 57 Times on 55 Posts
Likes Given: 51

Default

Quote:
Originally Posted by jpc View Post
PID with refrigeration equipment is bad... Will kill the compressor in no time.
That's certainly good to know and now that you mention it, I can clearly see why.
__________________
Catt22 is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 03:41 AM   #23
BrewBeemer
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2006
Location: an island, inside an atoll
Posts: 3,504
Liked 20 Times on 20 Posts
Likes Given: 7

Default

Just add a delay cycle timer to save the compressor from short cycling.
I've used defrost time delays from Safeway store refrigeration systems that I worked on they're great. Being free also helps matters with the desire to test wild ideas.

__________________

Last edited by BrewBeemer; 07-10-2010 at 04:12 AM.
BrewBeemer is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 04:02 AM   #24
Catt22
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2009
Posts: 4,998
Liked 57 Times on 55 Posts
Likes Given: 51

Default

Quote:
Originally Posted by BrewBeemer View Post
Just add a delay cycle timer to save the compressor from short cycling.
I've used defrost time delays from Safeway store refrigeration systems that work great. Being free also helps with the desire to test these ideas.
But would that not defeat the purpose of using a PID in the first place. The idea was to minimize the overshoot/undershoot with the PID. You toss a delay cycle into that mix and you would be back to a large temp swing. Perhaps I'm missing something though, as I have only a very rudimentary understanding of PID's and how they operate and it's likely to stay that way for at least a while longer.
__________________
Catt22 is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 04:20 AM   #25
BrewBeemer
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2006
Location: an island, inside an atoll
Posts: 3,504
Liked 20 Times on 20 Posts
Likes Given: 7

Default

The longer times between compressor cycles the more stable the temps in the fermenter's temp well i've found. Granted a wider temp swing within the keezer, who cares about air temp swings it's the fermenter's contents I want constant. I adjusted and tuned to the system at hand. This with a Johnson control kicking a relay for the compressor load. Granted a 30 year old POS keezer it still maintains a rather constant temp for fermenting is all I ask. No PID control here plus no short time internal keezer air temp swing worries.

__________________

Last edited by BrewBeemer; 07-10-2010 at 04:36 AM.
BrewBeemer is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 05:00 AM   #26
RDWHAHB
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2009
Location: Denver
Posts: 834
Liked 13 Times on 11 Posts
Likes Given: 1

Default

1) PID doesn't kill cooling equipment, short cycly times do. Short cycles should be avoided with t-stats as well.
2) PID is not overkill if you are experincng wild over/undershoots with your temp control. A good PID can be had for the same $$ as a ranco/johnson.
3) you want to cntrl the fermentation temp, not the air temp. Measuring anything other thanthe fermenting beer's temp introduces error.

__________________
RDWHAHB is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 08:08 AM   #27
BrewBeemer
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2006
Location: an island, inside an atoll
Posts: 3,504
Liked 20 Times on 20 Posts
Likes Given: 7

Default

Quote:
Originally Posted by RDWHAHB View Post
1) Measuring anything other thanthe fermenting beer's temp introduces error.
I've had my share of errors on my own without adding ideas from others.
__________________
BrewBeemer is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 06:39 PM   #28
jroot
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jul 2009
Location: Sun City, Arizona
Posts: 67
Liked 1 Times on 1 Posts
Likes Given: 2

Default

With due respect, I couldn't disagree with you more as to how to control fermentation temp. The ONLY thing you can directly control is the air temperature within the chamber. Keeping that as near to your set point temp is the only way to minimize the ferment temp swings which is the primary thing you want to avoid anyway. With the probe monitoring the fermenting wort the control will not kick on until there is a warming of the wort and then a big delay until it once again falls to the set point temp. However, with the control probe monitoring the chamber temperature the wort has a much greater chance to remain stable as the chamber quickly returns to set point temp.

__________________
jroot is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 07:18 PM   #29
samc
Feedback Score: 1 reviews
Recipes 
 
Join Date: Aug 2008
Location: Portland OR
Posts: 5,420
Liked 54 Times on 51 Posts
Likes Given: 29

Default

In my experience controlling the ambient air will eventually get you to the correct temps but it can take a lot longer to do so. Thermowells in my set up work better and while I might overshoot slightly, this tends to dissipate as I get close to desired temps. I can't explain it in scientific terms, it just works for me. As to sanitizing the thermo, it takes a minute.

__________________
samc is offline
 
Reply With Quote Quick reply to this message
Old 07-10-2010, 07:56 PM   #30
Bobby_M
Vendor and Brewer
HBT_SPONSOR.png
Vendor Ads 
Feedback Score: 2 reviews
 
Bobby_M's Avatar
Recipes 
 
Join Date: Aug 2006
Location: Whitehouse Station, NJ
Posts: 22,013
Liked 975 Times on 652 Posts
Likes Given: 28

Default

I've tried it all of those ways and having the controller probe touching the wall of the fermenter is the best compromise. It is affected by both the inside air as well as the fermenting wort. If it's in the center of wort in a thermowell, you'll undershoot the temp. The fridge will become a brick of ice before 5 gallons reacts. Putting the probe in a glass of water is the worst because it is as isolated from the wort temp as you can get. If the ferment is very active, it will be hotter than you want and take a long time for that heat to register in the satellite liquid.

__________________
BrewHardware.com
Sightglass, Refractometer, Ball Valve, Weldless bulkhead, Thermometer, Decals, Stainless Steel Fittings, Compression Fittings, Camlock Quick Disconnects, Scale, RIMS tube, Plate Chiller, Chugger Pump, Super Clear Silicone Tubing, and more!

New Stuff?
Bobby_M is online now
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
eHERMS temp probe placement??? Gabrew DIY Projects 5 07-01-2010 03:18 AM
Where to put themo probe for AC unit powered fermentation chamber Rhino17 DIY Projects 6 12-20-2009 02:33 PM
Unconventional temp probe placement?!? cyberbackpacker DIY Projects 0 11-24-2009 01:19 AM
Fermentation temperature control using internal probe stephelton DIY Projects 17 08-03-2009 06:30 PM
Probe help needed for fermentation chamber smellysell DIY Projects 4 07-30-2009 06:19 PM