With temperatures reaching 5°F to -25°F due to the “Polar Vortex“—also known as the “2014 North American Cold Wave“—homebrewing beer using a propane-fueled burner can be a challenge, or outright impossible.
The boiling point for propane is -44°F (it’s the boiling of the “liquid” in LPG that produces the vapor used for combustion in the burners), meaning that if you’re unfortunate enough to live where it’s reached temperatures that cold, you’re out of luck, though you could probably find better things to do than homebrewing on days that cold, anyhow.
If it’s “only” 5°F, you still have a chance.
You may hear talk of your propane tank “freezing.” As discussed, that’s perhaps not technically accurate. What those individuals refer to is the reduced rate of vaporization from the liquid propane such that the source requiring the vapor fuel (e.g., the burner) does not receive enough. The vaporization rate is both a function of the volume of LPG in the tank as well as a function of the ambient temperature. Generally, the more liquid-phase propane exists in the tank, the more pressure is exerted and the greater the rate of vaporization; likewise, the greater the ambient temperature, the greater the rate of vaporization. For an example (albeit, for a 100-lb tank), see the chart on the right.
If the “tank freezing” effect is due to both the the amount of propane in the tank and the ambient temperature, there are two obvious solutions if you’re stuck with a “frozen” tank. If you’re going to the heroic effort to brew in arctic weather, and you’re having trouble with a “frozen” tank, you may as well try both solutions:
- Partially immerse the tank in warm water, in an attempt to raise the temperature and induce a greater vaporization rate; and/or
- Use a tank with a greater volume of LPG; don’t use a near-empty tank. Either re-fill your tank, swap it out for one at a propane exchange, or use your full spare tank (you do have a spare tank, right?), at least until the weather warms.
If neither of those work, it could be that your propane regulator has also frozen, and it may be the culprit. The temperature of the LPG in the tank is at or below -44°F, which means the gas-phase as it passes through your regulator is also going to be, frankly, really damn cold. Pulling gas-phase propane through the regulator is going to rapidly chill it to sub-zero temperatures, especially on days when it is already near sub-zero. Frost on your regulator, even on relatively warm days, is actually (supposed to be) normal.
But, if your regulator is also in the presence of any moisture, this freezing/frost can result in a plugging of the vent hole, and a resultant non-functioning regulator (and no propane flow). Again, if neither of the above approaches to “de-frost” the propane tank itself seem to work, try ensuring that the regulator itself isn’t “frozen,” and that the vent hole is positioned downward so that any moisture can freely escape via gravity.
This is probably a good point to note that I am not a propane expert. While I have looked into it enough to be able to understand the basics, take this advice (as well as any other advice you read on the internet) with a grain of salt.
Happy cold-weather brewing!