How to gauge how much propanes left...

The tare weight is marked on the tank (look for 'TW' among the numbers on the tank). The difference between that and the actual weight tells you exactly how much you have. Too many variables to know how much time you'll get out of a pound.

Many (most?) people have two tanks. When one runs dry, switch to the other. Refill the empty one at your leisure.

FWIW, I use NG, so this is not something I worry about

 

A scale is definitely the best way to go. FYI: The "standard" bbq grill propane tank is a 20 pound tank, not a 5 pound tank. That's 20 pounds of propane (max capacity) although you will find that the actual amount places put in it varies. Most places only give you a 15 pound fill (75% of tank capacity to safely allow for expansion due to temp fluctuations) despite advertising a 20 pound fill. As mikehartigan mentioned, look for the "TW" as each tank (weight of the empty vessel itself) can vary. It is usually 17 pounds (plus or minus a bit).

 

I have a tank that I use for brewing, and I also have a BBQ tank as my back-up. My brew tank also serves as my back-up for BBQ'ing because that's just as important.

 

spray some water on the tank after the gas has been flowing for a while.
you will see a division where ice forms. that is the level of liquid propane.
Cheers.

 

Any weight scale will do, weight it new minus empty = liquid gas weight

 

I just pick the bastard up and give it a shake. If I hear a decent amount swishing around in there, I know I have enough to grill or brew. When there's nothing I can hear or feel in there, I know I am too close to the end to risk it without a full backup.

 

I have done 2 full all grain batches with mine and I am at half. The propane grill has a built in meter that weights it so I check with that.

 

Use some water while running it. Or after a while shake it and swirl and you can gauge the weight.

Best bet is to have two tanks. One empty use the other and rotate them out.

 

Just don't forget that the 2nd half may not provide as good of performance as the first half did. I find I get 3 full brews out of a tank and then it's best to use the remainder of the gas for lesser tasks like heating up initial strike water, adjusting mash temps, firing up the BBQ grill. Using that same tank and attempting to bring batch 4 up to a boil and/or boil batch 4 (especially in cold weather) is usually a bad idea. Either it takes forever to get to a boil and/or it produces a lackluster boil. This is dependent on many factors of course. I'm 3 kettle brewing with BG-14 burners (fuel hogs) and a 10 psi regulator. Ambient temperature comes into play as well of course.

 

Hell yeah, that's awesome!

 

No, they give you 15 lbs (some give you 17) because it's cheaper than 20, and 99% or their customers don't know they're not getting a full tank. There's plenty of room in the headspace to allow for any expansion, and the pressure doesn't change with the volume of liquid.

I could be wrong, but the laws of Physics suggest otherwise .

 

I usually see signs at propane places about either a 75% or 80% maximum fill policy. Some signs say it's a state law while others say it's a safety precaution. Now if you believe that 20 pound tank actually has a 24 pound capacity (when including head space) then yes I agree with you that anything less than a 20 pound fill is ripping a customer off.

You are probably right. Perhaps I'm just drawing propane at a high enough rate to drop the temp. inside the tank which is lowering the evap. pressure leading to the burners not keeping powered up. The improved performance I then get from swapping the tank with another one probably stems from the new tank being warm rather than full. Next time it happens I'll try placing the cold propane tank in a bucket with some warm water in it and see if that remedies the problem.

 

You sir know your shit, good advice.

 

I'll second this remark. My local refilling locale fills 'em to the top. I.e, to 20 lbs.

 

It's called a 20 lb tank because it will hold 20 lbs safely. Any less is BS, even if it's State sanctioned (especially if it's State sanctioned, IMO )

 

Not saying your wrong, but you can't even fathom the possibility that it's called a 20 pound tank because that's the maximum capacity?

 

Are you getting fills from Wasatch Propane by any chance? They were my go to cheap fill when I lived in SLC. Also known for major explosions every 6 months or so... once took out a good bit of their block on 2700S. Though I'd agree, if you know what you're dealing with and are ready to boogie out of there fast, you'll get a very full tank at a ridiculously cheap price.

 

It is a remedy, but you might have to change the waster once it is cooled enough.

 

They were filled to 20 lbs safely for decades and, indeed, still are. Anything less is purely to enhance profits. It's like the 1 lb can of coffee that now weighs 12 oz. Or the 1.5 qt 'half gallon' carton of ice cream. Or the 5 lb bag of sugar that now weighs 4 lbs. How would you feel if a gas station posted a price a few pennies lower than a nearby competitor, but the fine print revealed that the posted price was for 3 quarts instead of a gallon?