Grant wrote:Yeah...dead on to what I was suggesting. It would seem to me then that if it is consistent, that it comes down to something with the portafilter basket, or perhaps the portafilter and water flow of the machine?

Are you always using the same basket?

I've tried using 2 baskets- the 14-18g & 18-21g Lelit IMS baskets that came with the Bianca. I've also tried using both the stock Lelit shower screen and an IMS shower screen. I couldn't discern any asymmetries coming directly from the shower screen (at least not with my naked eye).

Grant wrote:Also, I know my machine (Elektra A3) is very aggressive when it comes to water flow...rotary pump slams the puck with full pressure with no ramp up at all or pre-infusion. Do you have a video of the water flow out of the group head WITHOUT the portafilter inserted? Is there a more aggressive water flow from that side of the group head?

I don't have a video handy right now, but I'll make a video demonstrating the water flow from both the stock shower screen and the IMS one in a bit.

Grant wrote: I have started using a stainless steel puck screen which has helped immensely...but you can emulate this by using an Aeropress filter (or just cut a coffee filter to size) and placing the paper filter over the puck before inserting it into the group head, then trying the shot. The filter will diffuse the water flow more evenly.

Thanks for the tip! I've seen these puck screens here and there, but wasn't sure whether or not to jump on using one as I'm still such a newbie. My thinking was: if I can't get this right without the assistance of the puck screen then I need to get more skill/improve my technique.... is that naive of me?

Regardless, my other practical concern with the puck screen is getting the screen out after pulling a shot *embarassed*... sometimes I forget the portafilter in the grouphead and the puck dries up... has this happened to you with the puck screen so far? If so, how hard was it to get the screen out with the dried up puck?

Because I have nothing better to do I decided to remove the shower screen/gasket & the dispersion screw underneath it in order to see if the dispersion screw was asymmetric or if the water flowing directly from the group head looking funny. Well the water looks a little funny all right... it seems to favor coming out to the left. In the video below I use the flow paddle to vary the flow of the water. At lower flows the leftward tendency is very apparent. At higher flows it becomes less apparent, but I'm guessing there's still increased pressure towards the left. With all that said... what does HB think, is this an issue? If so... any suggestions to fix it?

Additionally the flow of water is choppy. I understand the Bianca is a rotary pump machine, but I guess I expected some sort of stream smoother before the water gets to the group head... maybe when the water is under pressure this stream smooths out.. what does HB think about the choppiness?

You likely didn't observe any change in the extraction after tamping and shifting the basket 180 degrees. To clarify, you likely observed the same extraction pattern initiating in the same spot of the basket - This would seem consistent with your conclusion(s) ?

danzimm wrote:Because I have nothing better to do I decided to remove the shower screen/gasket & the dispersion screw underneath it in order to see if the dispersion screw was asymmetric or if the water flowing directly from the group head looking funny. Well the water looks a little funny all right... it seems to favor coming out to the left. In the video below I use the flow paddle to vary the flow of the water. At lower flows the leftward tendency is very apparent. At higher flows it becomes less apparent, but I'm guessing there's still increased pressure towards the left.
video

With all that said... what does HB think, is this an issue? If so... any suggestions to fix it?

Additionally the flow of water is choppy. I understand the Bianca is a rotary pump machine, but I guess I expected some sort of stream smoother before the water gets to the group head... maybe when the water is under pressure this stream smooths out.. what does HB think about the choppiness?

I sympathize with you but also love seeing other people prepping there puck. Drives me nuts but I watch every time, lol.

In my opinion it's not your machines, baskets or tamper. What I saw you do with Wdt was not really a great example. Just get the grinds into the basket and when you Wdt, try small circular motions around the out side of the basket and the bottom of the basket, working you way towards the middle reducing the depth as you go.

Before I figured out what worked for me, I too was having some unevenness and usually always on the same side of the basket.

I've experimented with my techniques and Wdt, my goal is to create great coffee with as little fuss and noise as possible. I hope this helps, and don't worry as long as the coffee tastes good that is what matters.

Re" slight water left bias:

The machine may have a slight leftward slope at the group. This can be caused by counter, feet, group mount to face. It can be checked with something like this laid across the machined face. That the stream is centered not much above a dribble says this is a red herring.



Check them with a known true level as all faces may not be correct. Mark the true faces. The true face goes against the group.

Perhaps don't reduce the pressure so much at the start. The e61 ramps pressure by design and overextending the ramp may be detrimental. [Personally, I'd never own a profiling device not under automation. If I wanted to manually futz with pressure, I'd buy a lever.]

No pro goes through all home barista machinations and many pull excellent shots all day long.

IMO, puck screens are just one more NTB* WoFTaM†. And yes, I have several.

Is it possible to grind directly into the basket, perhaps with a funnel? Dumping the DumBer cup on the Niche in favor of a Koonan funnel improved consistency markedly. Other funnels that fit inside the basket added a decidedly bitter note. If I had to speculate, a less dense ring at the basket that over extracts. [WDT not implemented]

* Next Big Thing
† Waste of Freaking Time and Money

The video clearly shows the stream exiting to left when the FCD valve is closing down. I suspect the machine is level and this is an effect of moving the needle valve towards the closed position. There may be a rotational component of flow velocity (clockwise or counterclockwise) that becomes noticeable at lower flow rates and less noticeable at higher rates. I doubt it's a machine defect but I haven't removed the shower screen to see if my machine does the same thing.

Your extractions look OK to me except for being a bit on the fast side...most appeared less than 30s. How do they taste? Less OCD may lead to more coffee enjoyment.

An important check as previously mentioned is to prep the basket in the PF as normal, then rotate by 180 deg before locking into the group head. If the channeling occurs in the same spot as before (in relation to the PF handle), the problem is the water dispersion. If the channeling is shifted to the other side of the PF, the problem is your puck prep.

You might also find that you are overfilling the basket a little - dropping to a 17.5g dose could help this. It has given me donut extractions and channeling in the past.

Seems like we're getting to the point of repeating suggestions. Work on your prep technique and if you don't want to try a puck screen cut some filter paper into a circle and put that over your coffee and see if that makes any difference. Water doesn't always evenly come out of the shower screen on espresso machines but it doesn't matter so much on a well prepped coffee puck. If the prep is off you'll get channeling and it could be in the same spot each time.

CoolHandLukey wrote:Assuming an even tamp, It seems you have more espresso opposite the portafilter handle. You can confirm this hypothesis by keeping your current puck prep and turning your basket 180 degrees in the portafilter prior to extraction observation.

This is excellent advice.

However, this response...

danzimm wrote:Unfortunately after doing this I still get the uneven extraction :/

Leads me to believe the following bit of diagnostic advice may have been missing:

Was the uneven extraction exactly the same when you rotated the basket 180 degrees, or did the unevenness move with the basket?

If it moved with the basket, something about your prep is the cause.

If it stayed exactly the same, something about the water distribution is the cause.

Does this make sense?

If the issue rotates with the basket, you can break your prep up into steps and find out which step is causing the issue by rotating the basket at various points.

I.E. rotate 180 right before tamping. If the problem rotates with the basket, your tamp is not the root cause. If the problem stays in the same spot, your tamp is to blame.

If it rotates with the basket before the tamp, then rotate the basket right before the step before you tamp. Eventually, you will find the culprit.

I'm with others as far as less is more with puck prep. You want to disturb the grounds as little as possible to get a good extraction, but no less.

Good luck!

- Jake

There isn't much

One suggestion I would make, in general about your process, is that right before you lock in the portafilter to pull a shot, pull some hot water through to warm up the group head. Maybe you normally do that or I spaced and missed it.