claypriley wrote:That was an EPIC project! and an awesome read. There was so much information in there my head is spinning a bit....I read it in one sitting... that milling is beautiful (in all cases). Man, I gotta go have some espresso and think about all of this...... Great Vision and excecution of a mod! It is so juxpostion in that the lever machine is just so manual, and then to add a PID which is so not manual, Excellent..... Congratulations!

Thanks a lot

The PID La Pavoni works amazingly well too. It's been humming away every day, turning out great shots of espresso.

Ray

Ray,

On what temperature/pressure have you now settled for pulling shots? I've watched several of your YouTube videos and, as I recall, on one you pulled a shot with your PID set to 232 deg. F, and on another you used 240 deg. F.

Thanks for your amazing posts and videos.

dbacks wrote:Ray,

On what temperature/pressure have you now settled for pulling shots? I've watched several of your YouTube videos and, as I recall, on one you pulled a shot with your PID set to 232 deg. F, and on another you used 240 deg. F.

Thanks for your amazing posts and videos.

I've been using 234.0 for the last few months here. That seems to work pretty well for the coffee I've been using. I've been meaning to rig up a TC or RTD sensor in one of the baskets and see what sort of temperature drop there is, but I haven't had a chance to.

The shot I enjoy most are at 234.00 to 236.00 mainly. I use the single shot basket and about 10 grams of espresso. That seems to work best with one lever pull and produces a very smooth and balanced shot of espresso. I've tried it using the double shot basket and 16 grams, but the concentration of the shot is too much for me. I personally prefer a less intense shot and light crema. I usually aim for a pull time of about 25 to 30 seconds.

Ray

RayJohns wrote:I've been using 234.0 for the last few months here. That seems to work pretty well for the coffee I've been using. I've been meaning to rig up a TC or RTD sensor in one of the baskets and see what sort of temperature drop there is, but I haven't had a chance to.

Ray,
Thanks for your feedback. Although I don't have PID control, I find the pressure gauge addition to my pre-millenium Europiccola to be indispensable for knowing the boiler conditions at any time. Now, I think the next step for consistent, predictable shots is to know the group head temp when you start a pull.

To my way of thinking, this is the big unknown, especially since the group head temp will be constantly changing as the system is heating and as you pull multiple shots. I'll be staying tuned for any updates from you regarding a TC or RTD sensor in a basket. In the meantime, I'll be getting one of those liquid crystal temp strips (like those sold by Orphan Espresso : http://www.orphanespresso.com/search.asp?keyword=liquid+crystal&search=Find) to help understand what's happening at my group head.

The pressure gauge is very helpful for sure. When I have the PID controller set to 234.0, the pressure gauge is usually right at 10 PSI (+/- .5 PSI typically).

One thing that is nice with the PID controller is that, because the controller keeps the temperature of the boiler very stable, the overall temperature of the entire machine (including the group head) is also kept very stable. This seems to really help. I no longer have any issues with the group head over heating. It's more a situation, now, where the machine gets up to its normal operating temperature and just stays there - and that positively impacts the temperature that the group head maintains also.

Ray

RayJohns wrote:One thing that is nice with the PID controller is that, because the controller keeps the temperature of the boiler very stable, the overall temperature of the entire machine (including the group head) is also kept very stable.

Ray

The more I think about this problem, the more it seems there are probably many combinations of group head temperature and boiler temperature that should produce a good, or great, shot. The problem is there are probably even more that'll produce dreck.

If you keep your machine at 234 F long enough, stability will definitely be reached - the group head temperature at which the rate of heat input at the boiler connection is balanced by the rate of heat loss to the ambient temperature of the room. The problem is that at equilibrium the group head is going to be pretty darn hot. It won't get to the 234 F of the boiler (there will be a temperature gradient from the base of the boiler to the bottom lip of the group head), but I suspect it'll be north of 200 F - too high for a good shot.

I guess the question is, given a temperature of 234 F in the boiler, at what temperature should the group head be to pull that perfect shot? Or maybe a better way to say it, what group head temperature would be too high (or too low) to pull the perfect shot?

This is turning out to be way more complicated than it should be. Perhaps I'm overthinking this...

Dave,

I think the temperature at the coffee cake should be what one would normally think is ideal for espresso, which is between 198 and 202F with the exception of some dark roasts that may be pulled cooler to suppress some of the harsher flavors and acidity. You should be able to measure this fairly easily using a thermocouple over the lip of the portafilter, although it will fray quickly. But another way to test it is by taste. If it's too hot it will likely be bitter; too cool, sour. The liquid crystal strip currently sold at OE measures a higher range than ideal. There are temp strips that measure the lower temperatures ramping up to a shot.

I've been running my pre-Millennium Europiccola at generally .8 to .9 bars pressure when pulling a shot, which is a little higher than what Ray reports. 10 psi is equivalent, I believe, to just under .7 bars. (We'll meet in February and can actually sample what each other is brewing and we'll see by that taste test if our pressure gauges are giving comparable read-outs.) At that pressure I usually have inserted a cool, nearly stock portafilter, which has more mass than his bottomless portafilter. Also I generally leave the switches off unless ramping up to a shot or steaming. I rarely get burned or sour shots this way. My Millennium Europiccola has a pressurestat and idles at .85 bars. This is fine for lighter roasts but I cool the group a bit for medium and darker roasts by cooling the stock portafilter.

So I think, in general, I'm transiently heating my machine a little more than his and cooling it to about where he's pulling his shots. I'm not finding this hard to do.

drgary wrote:I've been running my pre-Millennium Europiccola at generally .8 to .9 bars pressure when pulling a shot, which is a little higher than what Ray reports. 10 psi is equivalent, I believe, to just under .7 bars. (We'll meet in February and can actually sample what each other is brewing and we'll see by that taste test if our pressure gauges are giving comparable read-outs.)

Mine runs right around 10 PSI on the gauge when I pull shots. I think since replacing the gaskets in the group head, it's kicked the PSI up just a hair.

I'm looking forward to meeting in February, although there's a slight chance my girlfriend might take my truck down south for a couple of weeks (around that time). I'll be left with just my sports bike, which of course, isn't conducive to transporting espresso equipment.

However, if I'm without the truck, it's possible I could talk my friend Adrian into driving (if that's okay with you Gary). Adrian is one of my main friends in this area who also loves espresso and he usually comes by anytime I get a new bean or make modifications to the La Pavoni that might improve the shots of espresso.

I'm hoping Anita will be back up here before the date of your get together rolls around, naturally.

Ray

Hi Ray,

We've got to get you up here. I'm going to have to sell a domain name or something to get a bigger house, though. Please come and bring your friend if you need to. However we're going to be pretty crowded as is unless there are no shows.

drgary wrote:Hi Ray,

We've got to get you up here. I'm going to have to sell a domain name or something to get a bigger house, though. Please come and bring your friend if you need to. However we're going to be pretty crowded as is unless there are no shows.

I'll keep you posted for sure. I definitely am going to do all I can to be there with the La Pavoni!

Ray