Hi,

I have a la Pavoni lever and an encore grinder. I bought a compak k3 touch that I changed its burr. There was inconsistency in my shots. At the same time I got a great deal on an old, unused la pavoni zip. I moded it to stepless. Dialed the Zip; dialing zip was easier, and consistency is much better, so I put the k3 aside and thought to sell it. Yet, I get some channeling with ZIP now and then. Then, I changed my tamping technique as follows:

I load the filter with about half my dose, tamp with little force, then load the rest, and tamp firmly. ---I am not sure if it has a formal name in the espresso world!!!!

No channeling so far with this technique. Went back to my K3, and dialing was easy, consistency improved a lot. I saw a couple of youtube's vids where they did this. I thought they did it for "dosing", since they almost filled the filter, then added a little coffee and tamped firmly. I did it on a whim, and it works wonder for me.

I never read or heard anyone advising to try this technique to get better consistency, or to avoid channeling at least. So, is it really better, or it is just indicating that my usual technique of tamping is flawed?

BTW, I tried WDT before this two-stage tamping, and it improved my shots, and I get "less" channeling, but it did not prevent it for good.

Yeah this idea gets floated around periodically... if there's any merit to the re-expansion of grounds I saw in my little clips then maybe there's less air trapped per compression.
Otherwise, let's hear hypotheses!!
The other thing could be, that by separating out in stages there's more attention to distribution of all the grinds around the basket, but tamping twice might lead to more chance for user error.

Not directly related, but I have found that a nutating tamp help eliminate channeling as well.

What about breaking in the burrs of the K3. Your problem with the K3 probably comes from that. Just be patient and give the burrs some time to break in.

I tried nutating before, but could not do it well. This was some time ago; I think I am better in making shots now, so I will try it again.

For k3 burrs, I actually ran about 3 lb of coffee through it. I think it is enough for its burr size? There is some clumping with K3 grinds, and I know WDT should take care of it, but results were not consistent before I changed to two tamp technique.

With both, La PAvoni zip and compak k3, I notice that before I use the two tamp way, to get rid of channeling I need to go finer, which requires more force to push the lever down, where the extraction becomes slow. So total time for a dose of ~12 g, and for a one ounce restritto, is longer than 15 sec. Coffee starts dripping after 5-10 seconds of pushing the lever down---the taste is good this way from the Zip, but k3 is inconsistent in taste. But, if I go a bit coarser to get nice flow then I get channeling "sometimes" with the Zip, and most of the times with the K3.

Now, with the two tamp, I get nice flow without channeling--so far--with both grinders.

MemPast wrote:So total time for a dose of ~12 g, and for a one ounce restritto, is longer than 15 sec.

It should be - 15 sec total is a pretty fast shot. I run 25 for a ristretto & 35 for a full 21 gm shot (30 out). You may just be grinding too coarse.

~15 second without the pre-infusion time. Right?

At home I use the Strega mainly with the HG1 or Mythos.
While in Europe for a longer stay I bought a Pavoni lever, that I used with my travel grinder, a Lido 1, and the original plastic tamper.
It worked very well from the first shot ...
Just grinded 14gr (from 13,5 - 14,5gr was my sweet spot), shaked the grinds well (in Lido's glass) and "poured" them in the filter in two or three "servings", tapping filter gently against the table in between "pours".
Then tamped nutation (with plastic tamper), with little force, just to make sure grinds were leveled.
Worked very well for me ...

Pardon my ignorance, but what is channeling? Coffee geek dictionary doesn't have this term.

When the grounds in the portafilter are not correctly distributed which causes spraying and uneven gushing when brewing the shot.

If you search "channeling" on this site, there are about ten pages of info.
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