Monitoring fermentation temperature.

I have my fermentation bucket sitting in a warm closet so I placed the bucket in a water bath (about 4" of water) with a shirt over the bucket to wick up water to keep it cool. I am trying to ensure I keep my beer fermenting in the proper temperature.

I have a thermometer sitting in the water bath that says the temperature is 65-70 degrees. I also placed a thermometer on top of my fermenter and it says the temperature is 75-80 (which is basically the temperature of the air in that walk in closet).

So I guess my question is, which temperature is the one I need to be concerned with and monitor to ensure I am brewing at the proper temp? Or maybe I should ask how do I best monitor the temperature of my brew as it ferments?

I appreciate any insight! Thanks!

Well the first thing you should do is determine the best temp for your yeast. All the yeast manufacturer's websites say what the optimal fermentation temp of their yeasts are for the particular strain. If I'm really concerned about what exact temp the wort is, I'll sanitize my temperature probe and stick in into the wort. They also make adhesive carboy thermometers, which will have a closer approximation to the actual temperature then going by the ambient temperature or water bath temp. The wort tends to be a few degrees hotter then your water bath and hopefully a few degrees below your ambient temp. From the temp of your water bath, I'm assuming your wort *might* be pushing it for *ideal* temp....but again, it depends on your yeast. I think 68 is a good average for most ale yeasts...though some are more forgiving about being brewed up into the high 70s. Even if you're fermenting at a higher temp, though, it's not the end of the world....you'll still have beer!

I like to use the LCD thermometers that you just stick on the fermentor... Just like the ones commonly used to monitor aquarium temperature. They are pretty cheap and will give you a pretty good idea of fermentation temperature.

Edit: +1 on picking a good yeast for your ambient air temperature.

I am doing the same thing at the moment to cool my carboy. One thing you can do to up the chilling effect is point a box fan at it, the water will evaperate faster and cool a couple of degrees more.

I also swap out 1gal jugs of water that i freeze every 12 hours to help cool it. I have not taken any tempratures, nut it feels cooler to the touch. Better than the 77degrees my house is at, I hope to be down to at least 71-72

Thanks guys.

I guess it sounds like the best thing I can do to know the temperature my wort is fermenting at is just to stick a liquid crystal thermometer on the side of the bucket.

This is the first batch of beer I have brewed. I am disappointed because it started out brewing at a much higher temp than I expected and warmer than it should have been (i didn't know to use a water bath for the first 2 days). I hope to get everything right for my second batch.