Hi there,I'm seeing that the 208F coming out of my Zojirushi is around 203
I'm really glad you're having fun with the TWIST.
Regarding temperatures, we tried using a couple of Zojirushis at the SCAA expo, but we found the temps to be too low. By the time the water flows out the spout, it just isn't where it needs to be. So we picked up a couple of $20 electric kettles and found them to be a better and cheaper solution. (If we are demonstrating in a cafe, we'll often pull the water from the nearest commercial espresso machine and then steam it to bring it up to a boil.)
Best results will always be had using freshly boiling water. It's so important we mention it twice in the User Guide. Just get everything nice and hot beforehand and you will have much better results.
The N2O gas doesn't really have any impact on the water temp, although that's a fair assumption. We designed the TWIST so that the gas travels from deep inside the handle up a very narrow channel through the actual twist in the TWIST. This acts as a big heat sink/radiator, helping to bring the gas up to ambient. It then hits a channel buried deep inside the walls of the water bowl that is extremely hot after a pre-heat. By the time it makes it to the top of the chamber it is nicely warmed up. It also has about 1/200th the thermal mass of the water and metal, so it really doesn't cool anything down.
By the way, Intelligentsia evaluated the TWIST very carefully before bringing it on board. Now they sell it with a free bag of Black Cat so I hope you have much better results tonight with the 'Cat' tonight. We also prefer making shots naked, with the lower spouts removed. It helps keep the temp up in the cup, and it's darned good fun. It doesn't matter so much of course for other types of espresso-based drinks. We make lattes for two with the spouts on.
Looking forward to hearing how your further experiments go.