jasongcasale wrote:The Rancilio Machines with Xcelcius have temp profiling and yes as you are saying a cooler shot at the beginning and hotter at the end of the shot yields bad tasting espresso.
Starting and the the hottest temp you want and working your way cooler as the pressure drops would be ideal.
IE set point 203.5 all the way to 9 bar then dropping temp off a degree or half a degree with every bar of pressure you decrease the pressure.
This is just a theory I have with the pump pressure however somewhere in there probably lies the ideal range.
What you are saying is probably true once the theory is tested.
We do know starting hot to cool at a static pump pressure of 9 bars is ideal however thanks to the good folks at Rancilio.

Didn't know about that. It makes sense that lower temp at the end produces a better espresso. Now we only need to know how much lower and how to do it. Linking temp and pressure sounds like a good idea. Temp profiling shouldn't be hard to implement by itself either.

Rancilio, of course, disagree and assert that the rising temp profile is the tastiest... and I've seen it written that perhaps it's because their machine is the only one doing that at the moment?

decent_espresso wrote:I posted a picture of the advanced shot editor, which lets you have as many stages as you like, with whatever properties you like. The FLOW and PRESSURE profile editors are simplified vesions of the capabilities in the ADVANCED editor. It can do everything the mina does, and a bit more too.

oh, i am sorry i must have missed this. This is excelent. Have fun in Budapest. I wanted to come to Budapest to see the DE1+ in action and take part in Scotts roasting class but flight connections were terrible.

aecletec wrote:Rancilio, of course, disagree and assert that the rising temp profile is the tastiest... and I've seen it written that perhaps it's because their machine is the only one doing that at the moment?

They are not saying that - they are saying roasting "down" is the tastiest (decrease extraction as the pull progresses) for most regular and high roasts.

They do add that for Light roasts, increasing temperature (i.e. increasing the extraction throughout the pull) makes for a better cup. Intuition says that hard to extract coffees like a longer soak and higher temps.

Light roasts always make for an interesting pull dynamics (long bloom, lower pressure, higher temps, longer pulls, and now, higher temps).

What I find counterintuitive is trying to answer the question of what is the extraction difference between the average temperature of a pull - and a constant temp profile. If there is a difference - why is it there??

As an example, HX was neither superior nor inferior to constant temp boilers - it was just easier to dial in the latter and achieve consistency.

http://www.sciencedirect.com/science/ar ... 4616311530
These guys did say it, at least one of them from Rancilio and they used Rancilio machines and Rancilio funding.

Oh wow. Their marketing movie for the machine says otherwise. http://www.youtube.com/watch?v=N1AWmstSHpM

I don't have access to Science Direct - but from the summary it seems that increasing temperatures from 88-93C improves the flavor of everything they tasted. Hmm. For Robusta, Arabica natural and Washed Arabica.

Doesn't that cover everything?

AssafL wrote: Doesn't that cover everything?

Ha, pretty much!
They didn't do extensive testing and used "dark medium" roast. So it's interesting to see the comparison in media.

andreugv1 wrote:Will it be possible to change the temperature during the shot as well? I am pretty sure the hardware should allow it.
I wonder if, during a shot, the more you extract the more of what you extract changes, and if that can be good or bad (sincerely, no clue how it actually will translate in real life), but it might be that lowering the temperature as well as pressure/flow at the end of the shot, helps with a more balanced extraction, reducing bitternes. In the other hand a hotter temperature at the end is probably something that hasn't been done before (at least I can not see how a traditional machine would be able to overshot halfway through a shot).

A year ago, when I spoke to Rao about whether temperature profiling might be desireable, he articulated more or less your point, that the only way he saw it as useful was with a decreasing temp curve.

I then argued for an increasing temp curve, on the assumption that as the shot progresses it is harder to extract the remaining coffee material, and thus a higher temperature would be needed. He conceded that was a valid theory.

The DE1+ can do either, as well as letting you choose between a temperature curve that is water-temperature-only, versus an automatic water temperature but with a rising (or falling) temperature-at-the-puck goal.

Here's where you can do this in the Advanced shot editor that I'm currently working on.

We've upgraded to a high end "pick and place" machine to make our own circuit boards for our espresso machine. We like the control it gives us, to know that every part on the board is the one we chose. It lets us make short runs and also create small circuits for specific tasks (such as for a testing station) . Even better, the machine pays for itself with the first 1000 espresso machines we make, bringing the per-espresso-machine board cost down from $90 to $50.

We're calling this machine "Peter", as in "Peter Piper picked a shed load of components almost 500 and made them into PCB boards".
Here's a picture of a Very Happy Jeffrey with his new toy. You can see the puny old machine we previously used, to its right.

What - no BGAs? ?

Are you sticking with 0603? Or making life difficult with 0402? (I really hope no 0201 or pixie dust 01005 - but since no BGA why would you?).

Gicar are easy to solder/maintain as mostly 0603.