I have a Rocket Giotto, and am focusing on the brewing temperature issue. The supplier of a PID has indicated that 'there should be no problem' installing his PID on my Rocket Giotto, but he also volunteered that he has no experience with my machine type. After pouring over this and forums for hours, I have found repeated mention of HX espresso machines and PIDs, but cannot find a definitive conclusion that PIDs and pressure stat controlled espresso machines are compatible. (It's my understanding after reading all the posts that HX machines are all p'stat controlled).
My intuition tells me that substituting a thermostat for a pressure stat will be problematic. Is this a black and white issue of possible/impossible? If possible, has anyone has tried it, and has it been a success?

You can replace the p-stat with a PID. The usefulness of doing such for an HX machine is debatable. It is certainly not as stable and useful as PID'ing a double boiler. Bezzera makes an HX that comes with a PID, see link - http://www.1st-line.com/machines/home_m...E-full.htm

A PID is just a digital electronic thermostat. It will work with virtually any HX machine. It's value is that you eliminate the pressurestat which is a mechanical device. For dependability you could install an SSR in the pressurestat's. As far as its value in terms of temperature control, it would depend on where the thermocouple is placed. If you can get one inside the boiler, that would give very good control. if placed on the outside of the boiler, not so much. It usefulness would also depend on the machine. Some HX machines have shown excellent temperature profiles with a pressurestat.

Do you have eric's thermometer installed in the group? That tells a lot about what is happening in terms of temperature.

When you are done with the installation of the PID, let us know!

And maybe temperature is not the problem, what are you describing as a temperature issue?

Randy G. wrote:Do you have eric's thermometer installed in the group? That tells a lot about what is happening in terms of temperature.

Is this the same thing as the 'Scace 2'? That looks pretty nice, but for $500 plus a fluke meter??? It would be very interesting to know the temperature, but at that price, the 4 oz and GO procedure, plus taste buds, might be the best setup. Maybe Eric has an approach that isn't so expensive?

I'm gathering that the PID / Rocket combo isn't worth pursuing.

Thanks for all the help.

Bob

I am going to post here my generic opinions about PID'ing HX machines, a subject about which I have already said almost everything I have to say, in old threads I don't care to dredge up. The subject became moot for me a year and a half ago when I got my first GS/3, and I've become used to using double boilers so I don't think about this very much anymore. However, I have been using my old PID'd Vibe Cimbali Junior the last 2 weeks as I have been waiting on some parts to get my GS/3 paddle machine back into operation.

(1) It is unlikely that you are going to markedly improve the quality of the espressos you make by virtue of PIDing your HX machine. Machines differ and some will be more amenable to the installation and use of a PID than will be others.

(2) Much of what you might accomplish by PIDing your HX machine could also be accomplished more easily by turning your PSTAT down to a low boiler pressure with a mean setting of around 0.8 bar. This won't help the speed of your milk foaming, but if milk foaming is the most important thing to you, then tight temperature control of espresso shots is about the last thing on your list.

(3) Tight temperature control of espresso shots is grossly overrated. If the coffee you use is only good at one precise temperature, find yourself another coffee. Most good coffee will show differently at different temperatures, but it will not go from being great to being terrible over a range of 5 degrees F. You might like it more at one end of the scale than another, but there will be some things in the taste profile that are enhanced more by whatever temperature, within reason, that you use. If not, get another coffee.

All of the above being said:

(4) Pressurestats in most home machines are among the crappiest pieces of junk to be found in an expensive consumer appliance. They are hard to adjust and fail repeatedly, needing frequent replacement. A well installed PID will probably last you for the life of your machine, and if there is anything you need to replace it will be the SSR, which probably will cost a lot less than replacing a pressurestat.

(5) Adjusting the boiler temperature on a well done PID setup is hugely easier than it is to adjust the pressurestat, and should not require taking the case off the machine. It lends itself to rapid adjustment to your situation, such as if 5 of your best friends arrive all demanding a latte at the same time. Just crank up the boiler temperature and proceed.

I'm very glad that I did PID those two Cimbali Juniors and I was able to come up with a low temperature low flush volume program that works well in trying to make espressos on these machines at my home altitude of nearly 6000 feet, where water boils at a low enough temperature that large volume flushing is very unpleasant, to say the least.

ken

Marc wrote:And maybe temperature is not the problem, what are you describing as a temperature issue?

Inconsistent results in terms of taste (some good, some not so good), and surprising variability as to extraction time. I've controlled for bean age and weather by doing extractions separated by less than 5 minutes, tamping (using a clicker), quantity (I weigh the beans and grind everything), and grinder (Baratza Vario). Timing the extractions, the times vary by as much as 3x for the same volume. So unless I'm missing something, temperature is the only remaining uncontrolled variable. What else could it be?

Temperature won't vary the shot volume.

Sounds like prep.
How do you distribute the coffee in the basket?
Have you tried WDT?

Are you weighing what goes in the basket or what goes in the grinder?

Is your tamp level? Nothing else about the tamp matters