I have a problem. My shot consistency is lacking so I've adopted a few techniques to help distribution but I still have consistency problems. Here's my current technique:

Weigh the beans (extra 1/2 gm)
Grind
Dump grinds into basket (VST) with funnel attachment (OE funnel)
Weigh grounds (within 0.1gm)
Shake basket to level the grounds
WDT the grounds
Tap the basket to get grounds off the funnel
Tamp


After all that, I still don't see the even extraction that one would expect after all that prep. Occasionally I see such a disparity between the bottom of the basket during extraction that I know there must be a distribution issue.

I'll try to post a video soon.

(Edit): I realize my technique with the funnel is suspect but the extraction defect from that should be less flow from the periphery and not random distribution defects.

That is strange. For example on my Versalab there is no need for WDT and distribution is usually spot on. There is occasional spritz, but I think that might be more reflection on burr type (flat burrs) than anything else. On my K-10 I saw that doing WDT yields by far better extractions. I have no problems...

How do you do WDT?

Did you notice actual shot taste quality being a problem?

I use a 22 gauge needle to WDT and I perform little circles while rotating the basket ala spirograph (if you remember those things!).

Since I've been single dosing the Robur, I've had to resort to WDT and I notice a lot more fines in my grinds. When I was using the hopper, the grind quality was much easier to work with but I wasted a lot of beans.

Did you try your technique with different grinder just to isolate the area you should be looking at? My thinking is if you have same type of problems with different grinder then its likely technique problem...

Do you see the same problem with the second shot when you pull two shots in a row?

Dieter01 wrote:Do you see the same problem with the second shot when you pull two shots in a row?

The problem is sporadic. It can occur on the first shot or the last. It can occur on every shot (I pull 4 shots a day, and today was especially bad!). I think I have to post a video and let you guys watch what I do.

Also, maybe I will remove the auger from the grinder. It's the only difference remaining from the E version vs. the doser version. Maybe it is causing some grinding issues.

Judging from your routine, you're single dosing.
Have you tried loading a hopper, grinding, then weighing, say, in a basket, then pop the basket into the portafilter, tamp, etc.

HB wrote:I agree with Allon that single dosing with a Robur is problematic unless you rig a mini doser (e.g., like the one here or here). Without such a modification, the grind setting meanders towards more coarse as the weight of beans pushing towards the burrs diminishes.

Also, depending on the year of manufacture, the Linea may come with no gicleur or a 1.0mm one. Years ago when Counter Culture Coffee had Lineas in their espresso lab and changed them to 0.6mm gicleurs, I noticed a significant improvement in the "forgiveness factor" thanks to the slower pressure ramp up. It was certainly possible to pull good shots on it either way, but the margin of error was higher after the change.

I retrofitted the Linea with the Piero cap which has the 0.6 gicleur. You are right about single dosing, that is my problem. When I use the hopper, it all works fine. My issue is that I switch coffees every morning. My wife drinks CC's SO offering (depending on what is available) and I am currently working through my stash of Don Pachi. I don't mind wasting the CC beans but I can't bring myself to waste a lot of Pachi. There has to be some solution to the Robur or else I'll have to buy a new grinder which I don't want to do.

Here's my version of the modified Robur: