[midtex]

When a fermentation temperature is specified with a recipe, yeast type, etc, is the temperature the ambient temperature of the air around the vessel, or is it the desired temperature of the beer itself? I realize that when fermentation is slow the two should be about the same, but during vigorous activity, the beer could be several degrees higher than ambient. I am going to buy an electronic control for a freezer conversion and need to know whether the temp sensor should just be dangled into the chamber, or should I tape it to the container, or even sanitize and submerge? Thanks for your input.

[denny]

It refers to the temp of the fermenting beer.  FWIW, I feel that the yeast manufacturers ranges are generally too high.  I prefer to ferment ales (at least start fermentations) in the 62F area.

[blatz]

When a fermentation temperature is specified with a recipe, yeast type, etc, is the temperature the ambient temperature of the air around the vessel, or is it the desired temperature of the beer itself? I realize that when fermentation is slow the two should be about the same, but during vigorous activity, the beer could be several degrees higher than ambient. I am going to buy an electronic control for a freezer conversion and need to know whether the temp sensor should just be dangled into the chamber, or should I tape it to the container, or even sanitize and submerge? Thanks for your input.

the recommended temp is the wort temp and not the ambient temp, for exactly the reason that you have cited.  

Personally, I have my sensor secured to the side of the fermentor.  I have run a dual test before, using both a thermowell w/ thermocouple and thermocouple secured to the side wall of my conical, and found the difference to be less than 1 degree ( I measured every day after work for the first 7 days of primary) so I decided to return the thermowell to my buddy and keep to putting the sensor my little velcro pouch on the cone of my vessel and save the money for something more useful  

[bonjour]

It refers to the temp of the fermenting beer.  FWIW, I feel that the yeast manufacturers ranges are generally too high.  I prefer to ferment ales (at least start fermentations) in the 62F area.

I like to ferment mine warm, up to 65F. (wort temp, NOT ambient)

[midtex]

That's what I needed - thanks!

I am still new to homebrewing but have now made 3 batches of homebrew - all hefeweizen - all 3 fermented in my basement at about 68F ambient. My friends and family all love it and I entered one in the National Homebrew competition this year and actually did pretty well. My scores were a 32 and two 37's for an average of 35. First place in my region was a 42, so I was pretty happy. I got a nice "Silver" certificate in the mail. All judges comments lead me to believe that a lower fermentation temp will improve the beer, and yes, many of you on the forum recommended a lower temperature too!   So.... it's time for a temperature controlled chamber. I am going with the 5 cu.ft. GE freezer from Sam's for $154 and a Ranco single stage digital thermostatic switch from Pex Supply for $48.95. Not too expensive I reckon (and now I get to try making a lager too!).

[dak0415]

Great! You will not regret it, but do NOT get any probe even wet much less try to sanitize it and immerse it in the beer!  Tape it to the carboy under some insulating foam or buy a thermowell if you need to stick it in the beer.  I have a 120 volt 4" muffin fan inside my freezer blowing on the carboys.  The moving air cools the beer faster.  If you do add a fan, place the probe on the side of the carboy AWAY from the fan.

Dave

[richardt]

I also use a small section of clear packing tape placed perpendicular to the probe to attach it onto the side of my fermentation bucket.
Since I couldn't find any "insulating foam" laying around the garage, I improvised and folded over a paper towel several times to make a nice 8'' x 2'' rectangular several-ply "paper blanket" that covers the probe and a good portion (5 inches) of the cord.  Two strips of packing tape aligned parallel to and over the paper towel basically secures it to the bucket.

There are no condensation or evaporation issues due to the clear packing tape essentially "lining" the dry paper towel "blanket" that lies over the probe.

Cheap and easy.

[Hokerer]

Since I couldn't find any "insulating foam" laying around the garage, I improvised and folded over a paper towel several times to make a nice 8'' x 2'' rectangular several-ply "paper blanket" that covers the probe and a good portion (5 inches) of the cord.  Two strips of packing tape aligned parallel to and over the paper towel basically secures it to the bucket.

+1, I also use a folded paper towel (one of the blue "shop towel" kind).  I don't use tape, though, instead I use a giant rubber band and a twistie-tie to hold it in place.