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Keeping Temps consistent in swamp cooler

I just pitched 3L of yeast into my Octoberfest Lager last night. I pitched it with the wort at about 56 degrees. I added a couple of frozen bottles of water last night and the temp was 55 degrees when I woke up this morning. Once the fermentation really gets going will I need to add more than 2 bottles to keep the right temp? I have no idea how much heat the fermentation process throws off. This is my first lager and I don’t want to screw it up:). The beer did have a 1 inch krausen already so fermentation is already going.

The swamp cooler is sitting on my concrete basement floor. The ambient room temp runs from 58-64 degrees during the day.

You will need to play it by ear. The greater water mass you have the more it will be able to cool the beer. Similar to how long it take water to boil. With the same BTu’s, 5 gallon take less time than 10 gallons.

My guess it that you will be able to use the 2 bottles, changed out 3 times a day. Before going to work, upon getting home, and before bed.

If using larger bottles, 1/2g milk jugs, you might be able to change them out 2 times a day. Just depends on how much it has melted.

I just swamp cooler-ed my Kolsch. I could do that in my garage where it was cooler than your basement so I needed to change out the ice less frequently than I thought.

Two of the things I did: put an old t-shirt over the carboy to suck up the cold water and keep the top cool, too. When I took the carboy out the beer had a definite line in it though at the height of the cooler water. While the shirt stayed wet, next time I’ll be more intentional about pouring that cold water over top of it and hopefully that’ll help.

Second, I covered the whole thing with a sleeping bag to insulate it. That kept the air above a bit cooler. Just be careful you don’t knock off the cap/bung or topple the carboy with it.

A t-shirt and a box fan for some air circulation helps, evaporation actually carries a lot of heat off. Also keeping as much water in the swamp cooler as possible creaes more of a heat sink to keep temps from jumping up/down as much. I’d say it’ll take a couple bottles of ice in the morning and again in the evening to keep the temp in range during the peak of fermentation. Lagers don’t seem to get as crazy as ales, but they ferment longer (2-3 weeks).

I will add the t-shirt tonight. I don’t have an extra box fan though. I planned on keeping it in the primary for 3 weeks. Once the primary is done I plan on transferring it to a keg to lager. I have to sawzall a handle off one of my cornys so I can fit three kegs in my kegerator but it will be worth it. I want to make my father-in-law a gluten free lager for xmas so this will just end up being my lager keg.

I use coolers as opposed to tubs, which helps keep it a bit cooler as well as a towel covering everything. A sleeping bag was mentioned earlier, which would work better. As mentioned, the more water in the tub the better. I can keep my beer around 60F in a room that is 76F. I have to switch out bottles a couple times a day at least. I have to make sure if I’m brewing, I won’t be going out of town for the 1st five days of fermentation so I can keep an eye on temps. I give my beer more attention than my wife…she’s starting to notice…

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