My bottled beer is in a fridge in the garage, and the garage temp is about 28 F on a cheap thermometer. Still another day of arctic chill to come. Most of my beer is about 5 % ABV, and I remember reading that that is about the temp at which beer will freeze.
I fill the bottles with a bottle wand, and there is some variance in head space between bottles. Most bottles have at least an inch of head space. Is that enough head space to cope with expansion if the brew does freeze? I’d would want any broken bottles.
I opened the fridge about an hour ago and the beer was still liquid. At that time, I stuck the thermometer and a trouble light in there with a lit 100 watt incandescent bulb. I’ll check the temp inside in two hours and see if the heat from the light bulb is enough to raise the temp.
If not, I’ll probably bring the bottles inside the house, but I’m just curious to see if I need to do that.
I’d welcome comments and advice from anyone that has some experience or “war stories” with this. Thanks in advance for your help
A 100 watt light bulb produces a lot of heat. A 20 watt might be sufficient, but still check occasionally for the frig getting too warm.
You may have enough head space for when the beer becomes slushy. The beer will expand in all directions if it gets frozen solid. Bottles might start cracking.
I agree with flars. I used a fermentation fridge in a shed that often saw winter temperatures in the lower single digits during the winter months. I used a 40 watt bulb controlled by a Ranco controller and it saw very little on time even on the coldest mornings. If you don’t have a controller for your bulb, I’d try something in the 15 to 25 watt range and monitor it closely. Best bet is to bring the beer inside.
You could put a jug of tepid water into the fridge. That might be easier than moving lots of bottles. The insulation of the fridge is probably enough to avoid freezing.
Edit: You’ll also want to turn off the fridge if you put in a jug of tepid water to keep it warm.
I’ve seen crowns fail before the bottle cracks. Not sure why this is. Maybe in the early stages of freezing the expansion causes some liquid to seep out of the seal. When the liquid there freezes the gal is widened and the crown pops.