[4himarks]

I have a refurbished Danby kegorator I am turning into a lagering fridge. I have the temp cranked up as high as it will go, and the ambient temp is still below 50. The Oktoberfest I brewed on Labor Day (WLP 838 Southern German lager yeast) is supposed to do best at 55 degrees. I was planning to lager it until a work event on 10/23, but I just found out there is a unrelated competition I'd like to enter with a 9/28 deadline. I have one of those plastic strip thermometers attached to the fermenter that still reads 52, but it has been going down since brew day and 12 gallons is a lot of thermal mass.

Will I be OK, or should I do something to make sure it is done before the comp deadline? The results are being announced on 10/19, so the judging won't take place for at least a few days after the deadline, and it is a "hedonistic" comp, not BJCP sanctioned, so I just need to come up with a tasty beer, rather than hitting a particular style exactly. First prize is $500, so I'd like to do well...

[duboman]

You need an external temperature controller. Basically it will shut the fridge off when it gets below your desired temp and then kick on if it gets too warm

[morticaixavier]

or a timer that will turn the fridge on for 30 minutes every hour or 30 minutes every 2 hours.

[4himarks]

I have timers, but they will only turn something on and off twice in 24 hours. It will take a long time for 12 gallons to heat up though. How much do I have to worry about temperature fluctuations? The fridge is in my basement, so it would never get higher than about 70 even if I turned if off completely. I don't usually make lagers, so I don't have a lot of experience to go by. The OG came out a little low (about 1.040), if that makes any difference.

[morticaixavier]

I have timers, but they will only turn something on and off twice in 24 hours. It will take a long time for 12 gallons to heat up though. How much do I have to worry about temperature fluctuations? The fridge is in my basement, so it would never get higher than about 70 even if I turned if off completely. I don't usually make lagers, so I don't have a lot of experience to go by. The OG came out a little low (about 1.040), if that makes any difference.

I got a cheepo timer at the hardware store that would turn on and off in .5 hour increments for under 20$ that being said, I got an analog temp controller for 40$ sooo...

[AmandaK]

How much do I have to worry about temperature fluctuations?

More than you think. Temperature fluctuations are what cause our little yeasties to produce off-flavors and also cause them to go dormant. If you have a temp swing of, say, 3 degrees F - that is not a big deal. Temp swings of 10F or more can do a lot of damage to your desired fermentation.

The swing up will cause the yeast to produce more esters (not desirable in ta lager) and the swing down will cause the yeast to get sleepy, go dormant and then cause a stuck fermentation. Neither of these is desirable.

Look up the STC-1000 (or "eBay temp controller") and you'll see that a $20 controller will solve your problems.