Pulsating flow on Andreja Premium - Page 3

[dsc]

Hi again,

just as an update I thought I would descibe my progress (or lack of it) so far.

The coffee (Monsoon Malabar) is around 10 days old, which in my opinion is it's prime time (between 1 and 2 weeks). I can get nice slow pours with chocolate colour and loads of crema, but I still get side channeling. It seems like no matter what I do I get visible holes in the puck on the sides with doses lower than 16g. I tried almost everything, even ditching my needle tool and BBQ stick. With higher doses (16g and up) it tends to blond later, but still blonds non the less. When I knock out the pucks the middle usually breaks away easily, and I end up with messed up U shaped coffee cake in the basket, which holds pretty strong. There's a visible lighter area in the middle, which proves that most water goes around, down the sides.

Anyhow I will get a spare PF which I will convert to a naked one soon, so than I will try to upload some videos. I'm guessing donut extractions are going to be quite often when the new tool arrives, but I wouldn't be surprised to see flat extractions with sudden blonding for no apparent reason (other than side channeling).

Cheers,
dsc.

[CoffeeOwl]

Hi dsc!

I suggest coming back to simplicity, which could help you find yourself back in the map. Get to the starting point with a naked portafilter and all other things calibrated (like: accurate scales, calibrated standard size tamper). Maybe try grinding to a bowl and then spoon the grinds to the basket, polish and 30lbs tamp. But - have the tamp force calibrated. Then if you still have the trouble, change one thing at a time - and preferably let it be grind or the dose.
If this doesn't work, then maybe change your tamper to flat - I know many people here will disagree, but from my experience it does matter, however truly one should be able to work it over with technique anyway.

[dsc]

Hi Pawel,

your description matches the things I've been doing. I usually keep the tamping force constant (light tamps), my scale is 0.1g precise and I dose 15g (probably +-0.1g because some of the coffee can get stuck in the grinder). As you probably already realised I prefer an Italian way of dosing/tamping, which means less coffee, finer grind and lighter tamps. I have tried using higher doses (16g+), grinding coarser and tamping harder, but I didn't really like the taste and prefer the lighter way:)

A friend of mine is arranging a tamper for me which will be flat, so I will be able to see whether a different tamper makes a difference. I also ordered an NPF a few days ago and should get it before the weekend, so I will be able to see what's going on.

Cheers,
dsc.

PS. just out of curiosity, a you a member on Caffeprego forum?

[CoffeeOwl]

I did a small experimentation with the light tamps and I didn't have nice extractions (but honestly I didn't put my heart into it).
Since then I always do 30lbs tamp, but that doesn't mean higher dose - usually I put about 15.5g grinds in the basket, while my machine would accept 16.5 (at max). But anyway as I understood you did try lower doses with hard tamp too?

PS. just out of curiosity, a you a member on Caffeprego forum?

No. I only read a bit as guest some year ago.

[dsc]

Hi Pawel,

yes I did try various combinations of tamps and doses and they gave similar results. I will however try it all out again once the NPF comes, as I'm curious of the impact on the extraction.

As for the polish forum, have you ever thought of joining? It would be nice to have someone with a Vivaldi, as this is the machine are aiming for next:)

Cheers,
dsc.

[dsc]

Hello again,

yesterday my NPF arrived and I decided to try it out using two of the dosing methods that proved quite effective:

- single light tamp, dose 15g, WDT with my needle tool

- split dose/tamp, light tamp, dose 15g

Temps somewhere in the range 88*C-90*C, Malabar Monsoon was used, although it's a bit past it's prime time (will be more than two weeks now). I used the same basket as before, the ridgeless double from Synesso. I did everything the same and the only thing that changed was the PF. The effect was, well quite a surprise to say the least. It was a perfect pour, even, no donuts, squirts, dancing streams or anything. Just a nice thin stream in the middle, with a bit of blonding near the end, but nothing major as I would've thought. I tried another shot and it also went very good. Tried another one today, a slight ristretto and again a nice even pour. Tastewise, the first two shots were quite nice, the ristretto was a bit too harsh, although this was probably caused by the fact that MM might not like to be a ristretto.

Now the main question is, what the hell is going on? I mean changing a PF shouldn't really affect anything, or should it? The only other thing that changed was the gasket, which went from 8.5mm to 8.0mm to get the NPF to lock in the group. This means there's 0.5mm less head space and I can see it in the pucks as they all have shower screen impressions after extractions. I'm still surprised as I used to get soggy pucks and now with 0.5mm I'm getting a full screen impression?

Will upload some vids today and update this topic with some links.

Cheers,
dsc.

[Beezer]

I used to have the same problem pulling shots with spouted portafilters, but my naked shots always came out fine. It seems the problem is that the spouted PF would cool off a bit as I dosed and tamped, and the espresso would hit the cooler metal and turn blond. When I use the naked PF, the espresso never touches metal so it doesn't change color. The solution was to take the basket out before dosing and tamping and leave the PF locked into the group. Then drop the basket into the PF just before pulling the shot. Now my spouted shots don't suffer from early blonding.

See this thread for more discussion:

http://www.home-barista.com/forums/i-have-got-those-spouted-portafilter-blues-t5147.html

[dsc]

Hi Beezer,

well it makes sense and it might have been it. I don't know if I'm gonna go back to the normal PF in the next few weeks though:)

Here's two vids:

- Dose: 15g


- Dose: 14.5g



[the first one might not be available yet]

Both made with Monsoon Malabar, single light tamp and small twist to polish. The first one is a bit better in my opinion, still both are pretty even and tasted quite nice.

Cheers,
dsc.

[cannonfodder]

You are getting a little channeling but it is minor. The cone pulls to one side part way through the extraction. One side of the portafilter has a higher flow rate than the other. However, It is relatively minor. Could be an off center tamp or uneven distribution.

[Elbasso]

Good to see that you got the naked PF dsc!

What puzzles me about the second video is that when the beads start forming, they form really quickly but then they slowly coagulate and slowly start to develop a cone. I've never seen this behaviour on my naked shots. When "my" beads form, the flow rate seems to stay more constant, resulting in faster cone-forming. Anyone have ideas where the difference comes from?

Cheers,

Elbasso

[HB]

It seems the problem is that the spouted PF would cool off a bit as I dosed and tamped, and the espresso would hit the cooler metal and turn blond. When I use the naked PF, the espresso never touches metal so it doesn't change color.

A cool portafilter is causing blonding?!? If that were true, wouldn't a cool espresso cup cause blonding too?

Here's two vids:

The first showed no channeling of any consequence. The second had the telltale tulip-shaped cone followed by barberpole striping. That's the sign of a dead center extraction. You can let it run a couple seconds into this sort of pour, but longer than that and it's only diluting the espresso with dishwater.


Hollow cone forms the "tulip"

When "my" beads form, the flow rate seems to stay more constant, resulting in faster cone-forming. Anyone have ideas where the difference comes from?

I'll guess excessive fines migration to the bottom due to vigorous WDT stirring. Such extractions are "front loaded", i.e., start off slow and gloppy, then let loose at the end.