Hey BN Army,
I have a question for those of you using fermwrap. I have a beer fridge with a Johnson controller that I want to use to cold condition my kegs/bottles, while also fermenting ales. I was recently listening to an old episode of Brew Strong and Jamil mentioned he was able to ferment a lager and an ale in the same chamber by using fermwrap with a temp controller to maintain ale temps.
As a result, I purchased some fermwrap and attached it to my temp controller. I ran a test using a carboy with just water to see if the fermwrap would be able to maintain the proper fermentation temp so as to not ruin a batch of beer. The fridge naturally runs around 40F and I like to ferment my ales around 67F. I noticed right away that the fermwrap had some difficulty maintaining this temp, which I somewhat expected since the specs on fermwrap state it will raise the temp around 20 degrees higher than the ambient temp. However, I noticed many individuals state they were able to achieve a greater differential when the insulated their carboys.
So I bought some radiant barrier insulation from Home Depot and wrapped my carboy and noticed that it was able to maintain the 67F temp for multiple days. So I brewed a batch of Janet's Brown and insulated my carboy and set my controller for 67F. The temp held great for 6 days and then on the seventh day, after I raised the temp to 70F for a diacetyl rest, the temp started crashing rapidly. I removed the carboy from my fridge and allowed it to finish out at room temp which was pretty steady at 70F.
I mentioned this problem to MoreBeer, whom I bought the FermWrap from and they suggested that I insulate the carboy more since I was trying to maintain a temp more than 20 degrees higher than the ambient temp. So I brewed a batch of Jamil's Evil Twin and insulated the carboy with three times as much of the radiant barrier and even covered the barrier with an old sweatshirt. The temp held great for the first 4 days and then started crashing to 63 on the 5th day.
Just curious if any one else has had this problem or has any solutions to overcoming an almost 30 degree differential in ambient temp. Thanks.
Bryce