After posting in the "post a pic of your home espresso setup" thread, I got a PM about my machine, below.



I've done a couple of modifications that I've been using for the last month or two and been quite pleased with. Basically, I've wrapped PID controlled heater blankets around the grouphead to bring it up to shot temperatures without a warming flush. Keep in mind that the zaffiro is a single boiler machine. This might work with HX's, although I'm guessing benefit would be less as the cooling flush is already bringing the grouphead up in temp. Finally, this might have applications with lever machines, especially since the grouphead of a lever machine can hold a small amount of water for finer temperature control.

I'm finding that i set the PID in 1 degree increments, and usually see about a 1 degree delta on my grouphead thermocouple during the shot. It may be possible to tailor the temperature profile of the shot using this mod, but I've been going for stable profiles so far. I can't measure temperature at the puck currently, and since there is a blanket wrapped around the outside of the "saucer" that may be different from what i'm reading on the thermocouple. However, the PID is hooked to a second thermocouple under the white rectangular insulation on the top of the "saucer," and usually reads within 1 degree of the screw thermocouple.

I'm getting bogged down in details. The point of this post is to let E61 guys know it is possible to actively heat your grouphead, it improved the quality of my shots, and i'm willing to continue this thread with detailed explanations if anyone else is interested in undertaking a similar project.

Finally, just in case anyone noticed, i don't keep my grouphead at 187 degrees. I had just plugged in the blankets. (it takes about 5-10 minutes to warm up).

popeye wrote:...I've been going for stable profiles so far.

Very slick modification!

Mike Walsh and I talked about a similar modification for temperature profiling instead of attempting to improve flatline temperature stability. For example, heat the grouphead to a few degrees over the desired brew temperature and set the boiler temperature to a few degrees below the desired temperature for a standard "HX hump" brew profile. Jim talked about the impact on taste as part of the Producing Different Brew Temperature Profiles in the HX Love article but we've never had a means of reliably manipulating such a profile on demand. If you want to give it a try, I am very interested in your findings.

(Too bad the Quickmill Alexia is gone, it would have made a great platform for this modification.)

popeye wrote:I had just plugged in the blankets. (it takes about 5-10 minutes to warm up).

Where did you source your blankets?

popeye wrote:The point of this post is to let E61 guys know it is possible to actively heat your grouphead, it improved the quality of my shots, and i'm willing to continue this thread with detailed explanations if anyone else is interested in undertaking a similar project.

I'm very much interested. In my case, I have a Reneka Techno, whose steam boiler, brew boiler, and brewhead are all bolted to a 1.5 cm brass plate, fairly close to each other, which means that the nose runs a bit cold and it takes about a half hour to stabilize when I take it out of ECO mode, in which the boilers are allowed to go down to 70 C or so. Since the heads of the brewhead attachment bolts, as well as the instant tube fitting feeding it, protrude from the top of the plate, I couldn't use a ring heater, so this material looks like it might be ideal.

I'm also curious about why you chose to use two heater/PID setups, rather than controlling both blankets with one.

Best,
David

DavidMLewis wrote:I'm also curious about why you chose to use two heater/PID setups, rather than controlling both blankets with one.

The display mounted in the machine faceplate is the boiler PID. the green display only reads the E61 grouphead screw temp. The final display is of the PID that controls both blankets.

I sourced my blankets from http://www.omega.com, but I think they can be found cheaper elsewhere. I went with the glue backed ones, but once you remove them they lose the glue and i haven't found a good way to re-attach them.

Hi,

I'm getting a bit closer to trying this. I see that you used the Kapton blankets rather than the silicone-insulated ones. Any reason? And given that a blanket around the group-head is almost certain to be splashed at one point or another, how well-insulated are the contacts at the blanket end? And on the third hand, were you using a type-K or type-T thermocouple? Thanks in advance.

Best,
David

DavidMLewis wrote:I'm very much interested. In my case, I have a Reneka Techno, whose steam boiler, brew boiler, and brewhead are all bolted to a 1.5 cm brass plate, fairly close to each other, which means that the nose runs a bit cold and it takes about a half hour to stabilize when I take it out of ECO mode, in which the boilers are allowed to go down to 70 C or so. Since the heads of the brewhead attachment bolts, as well as the instant tube fitting feeding it, protrude from the top of the plate, I couldn't use a ring heater, so this material looks like it might be ideal.

I'm also curious about why you chose to use two heater/PID setups, rather than controlling both blankets with one.

Best,
David

David:

Email Andy Scheckter (I can never spell his name rite) and ask him for the part numbers of the rope heater and water-curing epoxy that he supplied Sasha Perl several years ago when we did this to Sasha's Brasilia. It changed the Brazilia from a real piece of feces into a pretty decent machine.

-Greg Scarce

gscace wrote:Email Andy Scheckter (I can never spell his name rite) and ask him for the part numbers of the rope heater and water-curing epoxy that he supplied Sasha Perl several years ago when we did this to Sasha's Brasilia.

Hi Greg,

It was Sasha's machine that first made me want to do this. The problem with doing it that way on the Techno is that the brew-head is bolted through the plate from the top, so that if you put the rope and putty up there, you would never again be able to remove the brew-head if you needed to. I haven't needed to since I've owned the machine, but it still makes me nervous to make it impossible. The idea of wrapping a $25 heater around the group bayonet is, therefore, more attractive. I was a bit concerned about a radial thermal gradient across the brass dispersion block, but Andy convinced me not to worry about it. On the other hand, if the putty is removable somehow, that would also be reasonable. Is it?

Best,
David

DavidMLewis wrote:if the putty is removable somehow, that would also be reasonable. Is it?

Maybe not. See Mcmaster-Carr item #3568K1:

To conduct heat and prevent burnout and premature failure when your heat cable can't make direct contact with the pipe, just mold this putty around the cable and stick it directly to the pipe. It withstands temperatures from -320° to +750° F and resists impact and thermal shock. Sets to a rock-like hardness in 24 hours.

I'd send you some, but whatever was left in my gallon bucket set up to a rock-like hardness.

FWW
Previous McMaster-Carr part number is a blank. One of these may do your job:

732 Multipurpose— For sealing, bonding, and gasketing metal, glass, wood, silicone resin, vulcanized silicone rubber, ceramics, natural and synthetic fiber, and plastics. Won't run on overhead and vertical surfaces. Begins to harden in 20 minutes. Temp. range is -76° to +350° F for aluminum, clear, and white; -76° to +400° F for black. Meet MIL-A-46106B. FDA and USDA compliant. NSF-51 and NSF-61 certified for use with food equipment materials and drinking water systems. UL recognized.

734 Flowable— Free flowing and self-leveling for filling cracks and crevices. Good for electrical insulation and encasing electrical terminals in adhesive (potting). Use on glass, metal, ceramic, and some plastics. Not recommended for vertical and overhead structures. Begins to harden in 15 minutes. Temp. range is -85° to +350° F. FDA compliant. NSF-51 certified for use with food equipment materials. UL listed.

736 Heat Resistant— Excellent for sealing and encasing heating elements in adhesive (potting), aerospace gasketing, insulation, and as a protective coating. Begins to harden in 17 minutes. Temp. range is -85° to +500° F. Complies with USDA and FDA Regulation 21 CFR 177.2600 covering indirect food contact. NSF-51 certified for use with food equipment materials. UL listed. Meets MIL-A-46016, Group I, Type I.
Richard / espressme