Struggling Mightily... - Page 3

A haven dedicated to manual espresso machine aficionados.
Chwecgn

#21: Post by Chwecgn » Nov 28, 2019, 5:47 am

leoniru wrote:
Long text
Thanx,

Jim S.

First Thing that Comes to my mind:

Do you let out the "false air" via the steamvalve while heating up?
During the heating process that should drop the Pressure by a good amount temporarily.

Then: I think the pressure should cycle between 0,9 and 1,1 to not get the water too hot while etracting.

pcrussell50

#22: Post by pcrussell50 » Nov 28, 2019, 8:20 am

By now, you already know to look for something else besides canned beans. That is big.

Some things about Lavzza Super Crema
1) you already know it is not fresh
2) it has robusta beans added to enhance crema when the beans aren't fresh. But robusta beans taste bad, so you have that working against you
AND
3) crema itself tastes bad anyway. It comes from fresh beans and good prep, but by itself it's nasty. So if you're getting close on flavor, you might want to spoon off the crema or wait until the shot cools and the crema dissipates.

A word about the MCAL... you might want to try a shot from it before the ground head becomes too hot. Cooler temps might help your situation.

-Peter
LMWDP #553

leoniru

#23: Post by leoniru » Nov 28, 2019, 8:43 am

I've never did any type of 'bleeding-off' of any air or pressure prior to pulling a shot.

I'm waiting on some fresh coffee beans to try, and have been trying to eliminate whatever seems to be affecting the boiled water's taste.
I've now tried a sodium bicarb solution followed by 5 or 6 rinses - each brought up to temp and then pulled through the group head and PF. Though not as strong, there is still a detectable difference between the water going into the machine and what comes out. I am lost for words with respect to trying to describe what I'm smelling and tasting - the only word that comes to mind is 'metallic'. The water is colorless & clear, but even after cooling a sample in the fridge, it remains evident upon smelling/tasting it.

Last night I filled the reservoir with a 50% white vinegar solution and am going to remove and flush today to see if THAT has made a difference, but what I was getting around to with respect to the pressure setting, was that throughout all these fill/boil/flush cycles, the machine seems to have settled nicely into a narrow pressure variation of about 0.1 bar from 1.0 to 1.1 AFTER the first liter or so of water is pulled through the group head.
Also, I noticed, or perhaps wishfully thought, that this off-aroma was not present ( or not as strong) in the steam wand's output, which obviously would lead one to suspect that this issue may be in the group head or water channel between reservoir and group head.

Just drew off most of a second fill of heated water through machine. Odor is very faint but there.
Third tank the same. All crystal clear and colorless though there has occasionally been some dark colored particles.
Will be pulling the showered, piston etc. out next because a look down into boiler looks clean as a whistle.

leoniru

#24: Post by leoniru » Nov 28, 2019, 8:47 am

pcrussell50

Thanx for the suggestions and comments. Will keep these in mind when I get the Redbird order in.

Marcelnl
Supporter ♡

#25: Post by Marcelnl » Nov 28, 2019, 10:26 am

heated water and steam IMO always smell slightly different, I'd take things slowly and one step at a time from here on. No more descaling, bicarb, vinegar etc, just plenty of fresh water to rinse and start with freshly roasted coffee and see what gives.
If the boiler looks clean it's not very likely that the grouphead is dirty enough (or at all) to cause bad taste. Lever groupheads stay quite clean.

rinse some more to get rid of all iatrogenic taste perversions and aim for 14 g Redbird in and 30 or so out and taste after a bit of cooling and stirring in the crema and report back.
LMWDP #483

leoniru

#26: Post by leoniru » Nov 28, 2019, 9:24 pm

Marcelnl
I tend to agree on the water difference WHEN HEATED IN ANY TYPE OF METALLIC VESSEL. Glass seems to be best for minimizing any changes.
I'll report back when my beans arrive.
As I don't consider myself to have an especially discerning palate, I'm hoping that it's not simply that I'm someone who just can't enjoy some decent espresso. Alas, there's only a nearby (and newly opened) Starbucks at which to obtain any form of espresso, but without knowing that they can satisfy serious espresso fans, I am skeptical of the experience I would have there.

leoniru

#27: Post by leoniru » Dec 04, 2019, 5:02 pm

Update time....
Received a fresh-roasted lb. of Redbird 'Northern Italian Roast', and began grinding. Found that I needed my Rocky on a much coarser setting to deliver a pull time of 30 seconds or so with light tamping on a 14 gm. dose. Results were more drinkable than the Lavazza.
I then decided to pull the piston assembly. I cleaned it up and installed new seals mostly because I had a set on hand. Can't be certain, but if the W seal belongs in the bottom piston groove and the V in the upper, well then, it appears that whoever last re-assembled things (and it could have been me!) had them interchanged.
Guess what?......the off-flavor/aroma of just the boiled water was vastly improved (nearly undetectable now) after doing this, but I had to dial in my grind again for a 30 second shot time. The shower head seemed to have quite a bit of hole-plugging grunge, so that might be why, or when I stored the machine last year, it was not clean enough, and so developed off-flavored grunge.
Again, there was an improvement in taste.
I now however have another issue; and that is a slight leak where the pressurestat tube is connected to the threaded lug on the boiler mounting plate. There is just a brass collared nut, which when completely loosened, does not allow the removal of the tube from the boiler. The tube is loose but will not even rotate completely around. A glance inside the boiler (from the fill port) reveals that my 1991 unit apparently reads steam pressure as this tube extends upwards from where it enters the floor of the boiler, to the upper third of the chamber, and it zig zags it's way to clear the heating element. Hence it cannot be simply drawn straight down and out from the bottom boiler plate.
Now I don't know if there was some type of packing on the inside of that collared brass nut, but if not, then what would possibly make a pressure-tight seal around the pressurestat tubing? The other end of the tubing - where it joins the pressurestat - has a proper soldered tapered flare fitting.
A glance around Stefano's website does not show this style of pressurestat (I have on hand one of the currently available style), or pressurestat tubing (only the style that appears to read water pressure as the tube is much shorter and doesn't extend up through the boiler's floor plate and upwards into the top area of the chamber).
I really don't want to change out the boiler floor plate and pressurestat tubing, but I don't know if this slight leak can be corrected otherwise.
Stay tuned.....

baldheadracing
Supporter ♡

#28: Post by baldheadracing » Dec 04, 2019, 7:37 pm

W in bottom; V up top. Use just enough grease (usually silicone) to cover the sealing surfaces. Here's a video (not of the MCaL, nor of EPDM seals) but to give an idea of how little to use on the seals and group, and where (skip ahead to 3:33 or so): http://www.youtube.com/watch?v=MbHiIr3GCMs

There should be no grunge anyhere in the group. People do go overboard with the grease ...

I probably have the same pressurestat in my 1985 model. That pressurestat tube nut/fitting can take quite a bit of torque. My experience has been that the pressurestat tube has to be placed/rotated to exactly where it was before it was unscrewed, or it will leak a very little (and frustrating) bit. I did not use PTFE tape or whatever, but I did use more torque on that nut then I would normally have used on a compression fitting ... just a very little bit of rotation was needed to stop the leak once I aligned the tube/pressurestat to where they were originally. IIRC, I went back a couple times to tighten it enough to get it to seal.
What I'm interested in is my worst espresso being fantastic - James Hoffmann

leoniru

#29: Post by leoniru » Dec 04, 2019, 9:53 pm

baldheadracing;

Thanx for that video link.
I used waaaayyyyyyy too much silicon grease based on that!
I doubt if repositioning will cure my leak as I ended up scoring the outside surface of the tube by twisting it back and forth while pulling on it in an attempt to remove it.
My only hope lies in removing the boiler and then the bottom plate which will then allow me to undo the slight zig-zag bends in that part of the tube within the boiler chamber and hence remove it. Then I should be able to effect some type of leak repair - preferably just placing some packing, or at worst, soldering (silver) the nut/tubing joint.
Can't see spending nearly $100.00 to update the bottom plate and tube.

baldheadracing
Supporter ♡

#30: Post by baldheadracing » Dec 04, 2019, 10:42 pm

You're going to want to remove that excess silicone grease.

For the pressurestat tube, before you dis-assemble the boiler, you could try undoing the nut and then 'filling' the nut and the various voids with silicone sealant and then tightening the assembly. If the leak is slow enough and isn't a straight shot then that may be enough. Allow at least a couple days for the silicone to cure all the way through - I'd give it a week or even longer myself. There are other sealants, but Silicone is relatively easy to remove if things don't work out.

A very slow technique is to use hard water and let the scale slowly patch the leak for you.

... and then there is always Alvin Product's Lab-Metal, although I can't recommend such a permanent 'repair.'
What I'm interested in is my worst espresso being fantastic - James Hoffmann