FWIW... in a fully utilized bar situation (continuous shot making), starting with a totally clean group, after 45 minutes build-up starts to become noticeable in the flavour of the shots and after a little more than an hour all shots start to degrade in quality. If you let it go 2 hours then rancid oil becomes a dominant flavour.

Water backflushing, portafilter wiggling, screen wiping... beyond removing some trapped particulate matter do nothing to address this. The only thing that fixes it is detergent.

The exception to the rule is stainless dispersion block machines (GS/3, GB5, new Speedster, etc), where removing the screen, rinsing it and wiping the block does wonders.

Obviously, if you're using spouted portafilters - then (unless the portafilters are stainless or teflon coated) you've got a whole other issue to address (soak, score, wipe, rinse).


-- while the above is all about bar usage and thus might be of limited direct use for home baristas, it is provided in order to give some perspective to the "oil is oil soluble" and "you don't need to backflush with detergent frequently" discussions. --

malachi wrote:The exception to the rule is stainless dispersion block machines (GS/3, GB5, new Speedster, etc), where removing the screen, rinsing it and wiping the block does wonders.

FYI- The Speedster uses a plastic dispersion plate. From Kee's site: "The dispersion plate reaches up through the bottom plate, so the water directly enters the dispersion plate. This plate is made in POM plastic, a fully neutral material regarding transferring heat. Also, fats and oils do not adhere easily to this material, effectively keeping it clean. This plate consists of two pieces offering a nicely divided dispersion, held in place by two screws."

malachi wrote:...
-- while the above is all about bar usage and thus might be of limited direct use for home baristas, it is provided in order to give some perspective to the "oil is oil soluble" and "you don't need to backflush with detergent frequently" discussions. --

Agreed. Glad you brought this up, as it was the reason I shared my observation. There is so much that we can all learn from the variety of observations found in this community.

That said, can't say that I agree with your observation about "rancid" oil dominating the flavor of shots after 2 hours of heavy use. I've had many clean and excellent shots at the end of a busy Friday morning shift, the last detergent backflush having been done the night before. YMMV, I guess.

cannonfodder wrote:Knock out the puck, pulse the pump for a few seconds to clear the screen, wipe the screen with a bar towel, pulse the pump again to rinse out the portafilter, wipe it out and put it back in the group. If I am pulling multiple shots, then I will wipe the portafilter out, a very short pulse to rinse the shower screen of grinds and prepare my next shot.

This is exactly what I do too, I'm not getting all this talk of pf wiggle. At least i can't get my mind wrapped around it right now at least.

lolgun wrote:I'm not getting all this talk of pf wiggle.

The PF wiggle doesn't clean the portafilter, but it can help wash coffee grinds off the group. After your next shot and cleaning routine, do a PF wiggle into a bowl. If you see coffee grinds in the water, then it's doing some good. If not, then it's a waste of time.

I use the JonR approach (PF wiggle with filled blind basket) in my cleaning routine after every espresso session. Even after flushing/scrubbing/wiping the group, the PF wiggle removes a small amount of residual grinds from the shower screen and gasket of my machine.

RapidCoffee wrote:The PF wiggle doesn't clean the portafilter, but it can help wash coffee grinds off the group. After your next shot and cleaning routine, do a PF wiggle into a bowl. If you see coffee grinds in the water, then it's doing some good. If not, then it's a waste of time.

Do you mean with the basket in?

RapidCoffee wrote:I use the JonR approach (PF wiggle with filled blind basket) in my cleaning routine after every espresso session. Even after flushing/scrubbing/wiping the group, the PF wiggle removes a small amount of residual grinds from the shower screen and gasket of my machine.

Filled blind basket? Of old grounds, or is this detergent? If it's detergent how often do you have to lubricate the lever? I was doing a detergent flush every week but found that my lube was gone very fast. I've switched not to a detergent flush every 2 weeks instead.

lolgun wrote:Filled blind basket?

PF Wiggle:
Place the blind basket into the PF and lock it loosely into the group. Turn on the pump and let the blind basket fill up with water. Then wiggle the PF handle back and forth, never to the point of removing it or locking it in. This allows water from the group head to wash remaining grinds off the shower screen and gasket.

I thought the PF wiggle was inborn behavior for coffeegeeks.

Hm, perhaps the wiggle is inborn, but I think my process is more OCD and I just skip the wiggle.

I tend to:
A) Pull a shot
B) Knock basket
C) Rinse basket under hot water
D) Flush for 5 secs (nothing in the Group)
E) Wipe with a Wettex the screen
F) Insert PF in grouphead and lock
G) Flush for 5 secs
H) Loosen PF, towel dry
I) Wipe screen again
F) Insert PF back into Group

I could probably skip most of these steps if I wiggle, but I've always been more of a twist man myself

Lots of Voodoo processes presented in this thread .

Some are missing the point, I think.

Above, mention is made of three "sources" that negatively impact espresso taste, summarized below and followed with cure proposed above:
1- coffee residue in the basket/filter and its underside in the portafilter bell as well as the portafilter bell itself as well; wiggle processes apparently are targeted at this.
2- old residue on shower screen side facing the coffee bed; wipe processes apparently targeted at this.
3- old coffee residue/oils behind the shower screen; backflushing with coffee targeted at this.

Comments:
1-if not using bottomless portafilter, just take the filter out and brush filter underside and inside of portafilter bell, next rinse.
2- rinse/flush briefly with no portafilter, tissue wipe may be fine but I prefer the Pällo brush and include the O-ring around the shower screen in the cleaning as well.
3- this is relevant to machines with 3-way valves in the group (like E/61) only (no lever-piston-hand-pump machines included here). I would not backflush with coffee as I am not convinced this is really the best solution and I also think, depending on the group/machine design, there are ways to minimize "coffee suck" back into the group when the pressure over the coffee bed is released at the end of the extraction.My approach to 3- is A- prevent it, B- frequently backflush with espresso machine detergent - the detergent will dissolve the oils and you do not force coffee into the brew head unnecessarily.

Regards
Peter

A thought just struck me. If I run a trash shot of old ground coffee, say from grinder adjustments or failed loads or something, or I use that coffee for a coffee backflush, have I now created a slight problem by coating the metals with oil from old stale coffee? In short, should I always use fresh coffee for this?