From the tests we've performed with the ThermoBarrel, we've had varied results. But in general, heat dissipates quickly during the initial phases of the mash. This is because the steel will absorb heat easily. This problem is lessened by pre-warming the mash tun and using a higher strike temp.
After the temperature has settled, the mash tun holds temperatures at a similar or better rate than most plastic coolers.
From our experience in brewing, most coolers don't have a problem with heat retention. So the ThermoBarrel's specific purpose isn't to compete on heat retention. It's to create a cleaner and more durable vessel than a plastic mash tun.
First, we've scrapped the false bottoms for the brew kettle. Nobody wanted them and we weren't too excited about them anyway. I removed them from the Kickstarter before. I'll delete them from the website when I get the chance.
The reason the ThermoBarrel's false bottoms are less expensive is because they are domed false bottoms which sit on the bottom and are uniform in size. So they use less material than the regular false bottoms and are easier to produce. So we are including them for $20 on the Kickstarter.
Here's a picture. (Note that the brass is only used for this prototype and it will be changed to stainless steel fittings for the final product.)
Lastly, we've added a third port to the ThermoBarrel. See
our most recent update for details.
