+1

Simply good logic.

pcrussell50 wrote:Yes of course good shots have been produced by machines with bad thermal stability. We've all made good shots with our Silvia's or similar SBDU's when those were pretty much all there was.


Anyhow, I think the point here is control. If a machine can't deliver a flat temperature profile, when no other profile is specified, then it also can't deliver you the temperature profile of your choosing, at least in any repeatable kind of way.

-Peter

A flat temperature profile is a goal because it's easy or at least a whole lot easier that trying to make a non flat profile repeat consistently. HX machines used in a very specific fashion pull off the non flat profile goal, but how they are used becomes more critical, because the profile will change wildly depending on usage.

It's also easy to measure and we know when the goal has been reached. Figuring out the best temperature profile other than a flat one is likely a can of worms. Maybe if you pick Illy medium espresso blend you can do it, but in the world of SOs its likely going to be at least as difficult as answering the question, what's the best machine and grinder for this pound of coffee?

A flat temperature profile is the second quantifiable temperature in trying to specify the perfect espresso machine, the first was stabilizing boiler temperature.

Ira

pcrussell50 wrote:Yes of course good shots have been produced by machines with bad thermal stability. We've all made good shots with our Silvia's or similar SBDU's back in the days when those were pretty much all there was.

Anyhow, I think the point here is control. If a machine can't deliver a flat temperature profile, when no other profile is specified, then it also can't deliver you the temperature profile of your choosing, at least in any repeatable kind of way.

It is for these reasons that I personally obsess over temperature stability, and probably also why the engineers who design espresso machines do, too.

Take a look at the OSLP on the lever boards, but essentially this isn't true. I control both the water temp and group temp and can repeat any profile within reason. It is essentially just a calculation of the difference in the group temp vs incoming water temp. Making them both the same results in a flat profile, and the further they are apart results in a greater cooling drop. On my machine I make a calculated temp (of the max temp) that you can see on the thread I'm testing and have compared with my Scace.

If you haven't tried a machine with a repeatable declining temp profile, IMO you're missing out. And for the record, I have a BDB as well to compare.

My theory is simple, and it's just the same as a good pressure profile. You decrease towards the end of the shot to lessen extraction of bitters. Then again I could be totally wrong on the why, but it's hard to dispute the effect in the cup.

???
Forgive me if I'm missing something, but are you equating the temp performance of a stock La Pavoni Europiccola to your OSLP lever? Holy apples and oranges, Batman!

I _do_ get the temperature I want out of my levers, mind... Through working according to it's heating and cooling schedule and tricks like inserting precooled portafilters or sucking in cool water into the group head, and pulling the shot before the temperature climbs above what I wanted.

The BDB, OTOH, performs according to my schedule, with the temperature I want, when I want it, with no ministrations to get it. I wish there were a way to tail off the pressure later in the pull with it, but...

-Peter

I edited the part of your quote that was relevant to my post, sorry about that confusion. You were talking about a flat temp profile so that's what I'm discussing here.

I'm comparing my DIY lever to what should be equally possible on this pump machine considering both use controllers and capable of more complex control systems.

John mentioned a mixing system, and so I think temp profiling is possible even if not available on release of the unit.

decent_espresso wrote:Yes, absolutely, we will make a 220V USA machine.


Peter, if you start a new HB thread, and post high res, high contrast photos of your baskets (and tell me the length of the diameter from hole to hole), I'll run Weiss' software (it's command line based) on your photos and post the results back on that thread.

Weiss' basket analysis software works on the command line: what I haven't done is make his program into a web page, which will take a bit of work.

Just a thought but, Sette has wifi capabilities to graph grind profiles from when I read. It would be pretty interesting if the new tech savvy budget grinder had software that could communicate with the new tech savvy espresso maker to create both grind and shot profiles in one package so you could take notes and easily organize how grind and shot profile work together to change flavors etc.

EspressoForge wrote:John mentioned a mixing system, and so I think temp profiling is possible even if not available on release of the unit.

I believe that temp profiling will be available on the first release. If I am correct we will then be able to find out what effect temp profiling has... I dont think it is available on other machines.

T

Trimethylpurine wrote: I dont think it is available on other machines.

T

Not on domestic as far as I know, but it is available on Rancilio's Xcelsius's and I think La Cimbali's new machine. Or was it San Remo, I can't seem to find the article.

Trimethylpurine wrote:... we will then be able to find out what effect temp profiling has... I dont think it is available on other machines.

Every machine has a natural profile, many of us have used plenty of machines, even at the same time to be able to compare.

Some levers are desirable not because of the pressure (though that is some of it), but because they have a natural declining temp profile.

But yes, a changeable profile on a commercially available machine, I'm also not sure of others. FWIW other than the OSLP, I've seen some other builds that attempted it but haven't seen reports on how successful the mixing idea was.

Once a machine gets to some level of temperature(s) repeat-ability, it makes more sense (ie, tastes better) to work on a better temperature profile than it does to make it even more repeatable.

Given the effect of room temp and the temperature of the grounds before brew, brew temp (not above the coffee temp) in machines isn't as repeatable as is claimed.

Some machine having a flatter temp profile than some other machine is pretty much meaningless in terms of taste/better (ie, is quite likely to be worse tasting). Ie, "impressively flat" is an oxymoron.