Actually, what gave me the confidence to use the 1500 watt heating element was when I searched for the PID I was buying on google, I found a lot of links to home-brewers who used these heating elements drilled into the side of big aluminum/stainless steel pots. They were using even higher wattage units to get quicker boil times.
It's great that we can so easily share information between different hobbies, isn't it? :-)
Oh, I also ought to mention one thing regarding the heating element for those who might not be familiar. If I remember correctly the National Electric Code indicates that a constant load (such as a heating element) cannot be more than 80% of the peak load rating for the circuit - which (I think) ends up being 1440 watts on a 15 amp branch.
It's almost certainly safe to operate on a 15-amp circuit, but if one is particularly worried about the letter of the law or insurance coverage if anything unfortunate happens, be sure to run on a 20-amp circuit.
Interesting, I wonder if this is a new development (can't find that in my 2005 NEC codebook). I did run across something else, though, 200.21B2 states that the total load on a single 15-amp receptacle cannot exceed 12 amps, which might also apply.
I guess I'm going to have to go back and re-read the whole section. This concludes the thread-jack. We now return you to the regular discussion.
The mash temperature needs to be pretty exact, and I (personally) find it hard to do fine temperature control with a burner. Even a few degrees variation during mash can favor different enzymes and result in inconsistent starch conversion or an alteration in flavor. I've never had much success trying to keep the temperature that steady for a full hour using a propane burner. That's not to say no-one else has success that way.
Besides that, I use a big 100 quart cooler as a mash tun to help keep the temp consistent which precludes using external heat.
My roommate was just using a burner and a pot to heat the water to the desired temp, and then he placed the hot water in a big insulated cooler, which keeps the temperature extremely stable for the hour or so while the warm water flows down into the sparging system in a second cooler holding the mash, unless I'm just completely confused about the process...
Yeah, if you have a cooler that consistent and adjust your temp for the measured thermal mass of the cooler it would work fine. Mine loses about ten degrees per hour at mash temp, however, so I need to adjust the temp pretty continuously during mash.
Of course, another part of it is just my desire to hack together nifty gadgets. :-)