Beer Forum

One recent question from the Brew Strong Q&A spiked my interest. This weekend I started using a thermowell + digital Ranco 1/4" sensor to control fermentation temp. Previously I had been taping the probe to the outside plastic insulated by a small piece of cardboard. I've noticed there seems to be a difference (outside surface reading vs internal wort). I would imagine consistency is the most important consideration for our own brewing, but when brewers talk about what temperature they are using for fermentation it seems to me the method of control is an important consideration in the outcome of a beer. e.g., Do you believe one or two degrees of fermentation temperature can make a difference in your own beer? Seems to me, when reading a homebrew recipe - or even a book of recipes, one important consideration usually missing is which method of fermentation temperature control was used by the recipe creator and that this CAN make a difference. Has anyone tried to quantify the methods used by brewers for fermentation control? Are we to assume Jamil and John are talking always referring to internal wort temperature control, and if so, why can't I find any ready-made products to accomodate the common carboy? i.e., No thermowell at my usually well-equiped home brew shop would accomodate my 1/4" digital sensor so I ordered a roughly built one online - nor do they carry dual hole #10 stoppers. The orange carboy caps are not air-tight and the dual stoppers usually sold with the thermowells dont' fit a carboy so I have to drill my own? Makes me think I must be missing something here.

Jamil insists that a probe, taped to the side of the carboy, covered in insulating styrofoam (or something similar) will give you an accurate reading. That's what I do, and have no complaints. I've never used a thermowell to compare to the temp in the center of the carboy, but there is a big difference in taping to the side, versus ambient. I insulate with that really soft, flexible kind of styro-plastic foam, that a lot of things are shipped with.

I also took to using the surface probe isulated with some neoprene or whatever can coozies are made of after hearign Jamil say thats sufficient. I figure if it's good enough for the pope, it's good enough for me.

I tried to outline my experiences here:
viewtopic.php?f=4&t=24290&start=12
viewtopic.php?f=4&t=24290&start=14

Your experience may vary, but my experience has been that a probe on the outside isn't always as accurate as a thermowell. The probe on the outside seems to measure the temperature of the glass sometimes, not the actual liquid. It may only be at certain times, and only a few degrees, but that matters to me.

For $14.00 plus shipping, and the price of an orange carboy cap, you can know exactly what the temperature of the beer is:
http://www.brewershardware.com/16-Stain ... owell.html

To me, it's worth the price many times over. It's far cheaper than a batch of beer that didn't turn out as I wanted.

I use a Better Bottle and have the probe stuck to the side with a rubber band, insulated by a wash cloth. I can't say my method is the absolute best, but it is very convenient, and works well enough for this brewer.

Thanks everybody for your responses. I'm impressed by the caliber of brewer that participates in this forum. BN is the best!

I tape my temperature probe to the side of a glass carboy and cover it with a chunk of 3" thick styrofoam. Am I trying to replicate someone else's beer? Never. It would be important to get an accurate reading if I was. The most important question to ask yourself is, "Am I brewing great beer?" How does it taste? If it tastes great than you have reached the goal. If it has defects and you can identify those defects as coming from temperature control than you should make some changes. If your trying to replicate someone's beer that has a thermowell and you don't you might set your temp a few degrees cooler. In the end you have to do what all great brewers do. You learn your system and minimize variables so you can repeat your successes.

I use a thermowell and stopper from more beer with a dual temp controller for the fridge and the heating pad wrapped around the fermenter. Not sure how accurate the temp controller is but I am assuming +/- 1F.