AND IT MAKES BAKERY GOODS TOO!?!? No wonder it is so large!
Make mine raspberry! --->

cannonfodder wrote:I have seen labs less well equipped.

The difference is, labs probably arrange things so that they can open the cabinet doors.

cannonfodder wrote:You mentioned heat produced during the grinding process. I have planned on putting a thermocouple in the grinder chute as close as I dare to the burrs to plot the temperature that is transferred to the grinds.

I observe coffee sitting in the hopper at 70F come out of the chute as 85-90F grounds. This is probably unavoidable (grinding necessarily produces heat from friction), and that kind of moderate temperature rise probably has little effect on flavor.

In commercial use, though, even big honkin' grinders like the Robur get very hot, and the temperature delta may be larger. But perhaps an even bigger problem is in the hopper. Beans waiting to be ground are slow cooked as they sit directly above the hot burrset. (I think this issue was first pointed out to me by Scott Rao, thanks, Scott).

More advanced hopper designs are in the works that should alleviate this type of hopper-related heat abuse.

Compliments on this great project !

It's like you guys are putting crack between the lines, I just have to keep on pressing ctrl-F5 again & again.....

It's unlikely that anyone reading this thread has to be convinced of the importance of freshly ground coffee in espresso. But just in case there are any doubters...

After pulling umpteen bazillion shots over the past few days, it was high time for a detergent backflush on my Vetrano. After the procedure, I used some of yesterday's leftover grounds for a seasoning shot. The resulting "double" blonded at 30ml:


On top of the crema was a thin layer of nasty yellow foam that I'd call "krema":

Go straight to the sink. Do not pass Go, do not collect $200.

For reference, here's a pour at 40ml using freshly ground coffee from the Macap MXK conical grinder:

cannonfodder wrote:Good lord Andy. I have seen labs less well equipped. That just underscores how far we are willing to go for the perfect cup and push the envelope of our equipment.

You mentioned heat produced during the grinding process. I have planned on putting a thermocouple in the grinder chute as close as I dare to the burrs to plot the temperature that is transferred to the grinds.

Recent work on grinders by several companies bent on improving them shows conclusively that the main heat source for coffee in the grinding process is heat from the cutting process, not heat from motors. Work on reducing heat to coffee should focus on reducing friction in the cutting process.

Preliminary conclusions here mirror my own a couple of years ago when I first got my Kony. I felt that the Kony accentuated brightness compared to my Cimbali Junior. The Robur is very similar to the Kony in terms of taste. I'm very interested in this thread. It's the most fun reading on the coffee sites that I've encountered recently. Test ON!

-Greg

Last post for the evening, a beauty shot from the A3 and Kony with some home roast. This is almost the end of the shot, about 1.5oz dispensed.

gscace wrote: I'm very interested in this thread. It's the most fun reading on the coffee sites that I've encountered recently. Test ON!

-Greg

This is just the start. John and Jim have access to some things we mere mortals don't. I am not going to spill the beans on them but there is some uber cool stuff in the works.

Excellent project! Thank you to all the participants doing the "work" on this very worthy subject.

I want to make one point that I think is pretty obvious but should be directly addressed. Heat from grinder burrs is possibly an important issue in a HIGH VOLUME SETTING but probably not to us HOME users. If your normal practice is to grind coffee for 1 or 2 shots at a time, separated by a period of non-use, it is debatable or maybe JUST PLAIN SILLY to claim that there is any benefit from a conical grinder, in a home setting, in this regard.

300 or 400 rpm (with less resultant heat production) may be important, but in a home setting I think this is in serious risk of setting off my BS meter.

There may (or may not) be inherent benefits from conical burrs and their grind products vs. planar burrs. If these benefits or differences are "real," I am highly doubtful that they come from reduced heat generation of any grinder in a low volume home setting.

ken

The work done on the coffee by cutting it into bits doesn't depend on duty cycle at all. Heat dissipated from doing this work is a constant. The difference between continuous duty as in shops and our usage is that heat gets transferred to both the coffee and the cutters. The cutting surfaces don't get replaced, so they eventually warm up in continuous duty. This is a second source of heat to the coffee. I don't see that any of this fun is gonna shed any light on high-temperature cutter issues, but it doesn't have to either since this isn't pro-barista.com.

I presume that there are other reasons as to why speed is kept low with conicals besides heat. I'm guessing that low speed increases cutter life.

-Greg