LewBK wrote:Anyone find that lungos taste better on the Robot than espressos?

I've found the opposite, shorter is better in my experience.
Might have something to do with the beans used, temps, technique, how hard you pull, et cetera...

This is where I am. Add to the et cetera--subjective taste of the user?

Yep.

jpender wrote: Why would the piston be the most important?

Piston + basket are the most directly in contact with the brew liquid.

The portafilter has a high amount of metal mass but only the top edge of the portafilter is in direct contact with the basket, a small contact surface that only allows limited heat xfer for those 20-30 seconds.

And the rest of the robot body is only in indirect contact with the piston, via the arms attachments, again not a big source of heat xfer during a short time period.

But since preheating the basket and/or piston is a pain, I only preheat the portafilter, and I don't think I have the palate to detect a real difference + I do latés mostly and maybe there isn't any difference of a bit extra heat anyway.

There's normally a column of air between the piston and the brew liquid.

You can just make it out in this Cafelat Instagram video.

I aksed this in an older thread but based on your experience with the robot do you guys think that a small pad heater for reptile tanks applied to the piston would work to warm it up without presoaking hot water?

Example: https://www.petco.com/shop/en/petcostor ... ater-95290

It's really hard to discern that column of air between the piston and water in the video of the transparent PF. If you start with 1cm or less of space between the water and the top of the basket and apply 6 bar or more it's going to be a pretty thin column, something on the order of 1mm. And it will be very hot, moist air as well. At the same time, the distance between the basket and PF is also pretty small, at least up higher on the basket. I really don't know how to calculate the whole heat transfer problem. That's why I'm measuring examples instead.

One thing to consider is that a preheated PF will start having an effect as soon as PF and basket are mated whereas a preheated piston won't matter as much until the shot starts.

I haven't collected enough data to say anything definitive. I'm just another monkey in the jungle. But it "seems like" preheating the PF has a significant effect upon the initial brew water temperature whereas preheating the piston has a greater effect upon maintaining the temperature over the course of the shot.

Freddofl wrote:I aksed this in an older thread but based on your experience with the robot do you guys think that a small pad heater for reptile tanks applied to the piston would work to warm it up without presoaking hot water?

Example: https://www.petco.com/shop/en/petcostor ... ater-95290

This idea doesn't strike me as practical, I'm not sure a reptile pad would get the piston hot enough to make a significant difference. I could be wrong, and I find pre-heating the piston unnecessary for my tastes, I just preheat the portafilter and basket on top of my kettle while heating the brew water; this doesn't waste any water beyond any evaporated water vapor.

^^^^^^^^^this. And after the first the second may taste different.

The first and foremost reason we purchased the Robot is ease of use.

In my experience:

• Dark Roasts - No preheat necessary, I've even been using 97C water to tame bitterness. Super low effort for great shots.
• Med Roasts - Preheat portafilter and basket in kettle, 100C water. A little more effort, but worth it.
• Light Roasts - Preheat portafilter, basket, and piston for the best flavor, 100C water of course. A lot more effort to preheat everything, but at least it's possible to get a good shot from light roasted beans this way. Most times I don't feel like the effort it is worth it and I enjoy my light roasted beans in a pour over.