Help needed!

[Stickleback]

I am going quite mad with my coffee setup at present, and just cannot get a consistent cup no matter what I try.
I have: a La Cimbali Junior D (20 years old?); the group handle is original and I use a double basket; a Rancillio MD50 (grinders replaced last year); and I roast my own using a KKTO (about 600gm a week) . I've had this set up for about 5 years.

In a nutshell, my ristretto tastes like rubbish and the difference between a half decent pour (which is still a bit dodgy) and something that either runs through the machine like water, or clogs up the machine is incredibly fine - almost arbitrary. What would seem like a normal minimal adjustment to grind, dosing, or packing technique can change a pour from clogging to running through.

What I have done so far :
I did a barista training course when I first got the machines;
I clean the Junior thoroughly every few weeks;
I have an inline water filter and it was professionally descaled last year - not that it was bad;
I've had it professionally serviced twice in 5 years;
The burrs in the grinder were replaced last year;
I've tried several packing methods, including the Weiss, and tapping regularly while dosing.

Confessions : my tamper does not fit the basket perfectly snugly, although it is pretty close - maybe 1 to 2mm off snug;
I don't use the hopper on the grinder as it's too tall for the space in the kitchen, and I only grind what I need at the time. Given the grinder does not spit out all the coffee grinds, I tip it forward and sweep out the shute each time (after its stopped of course);
Until recently I've only drunk milk based coffees, but now I prefer ristretto - it's possible my technique has always been faulty, but I don't think so...


Anyways, I am fairly sure the roasting is sound, and the aroma (and taste) of the beans is good, so I am fairly sure the problem lies with machines and technique. Any tips, tricks, advice and places to look would be greatly appreciated.

Cheers

[Stickleback]

Oh, and I also weigh my beans to try and standardise the amounts, but I haven't weighed them after grinding into the basket...

[Journeyman]

OK, you might have several symptoms, which may not be related. Some things that might help diagnosis...

When you get a 'pour' instead of a choked basket, how is the pour? (not the taste) Does it come out looking good? Is it thin & black all the way? Do you get the lovely light brown crema look at any stage in the pour? Does it blonde early?

When you say 'ristretto tastes like rubbish' what do you mean? Bitter? Sour? Thin taste?

If you run a shot with no basket, what is the water like? Does it sputter or drip instead of pour steadily?

I don't know the machine so this might not be relevant, but is it a step-change on the grinder or worm drive with no discrete steps? The abrupt change for very little alteration suggests there's something in the burr set up that isn't right. I can go from clogged to almost a gusher on my SB EM0480 in 2 steps (or 1 sometimes if I forget to change my tamp pressure) but the 480 has 24 steps in 90º of turn, so they are large changes. To get that in a Rancilio, from what I have read on here, suggests something is magnifying the change. Can you pull the burr assembly apart and look for anything not right? Or maybe something in the drive that might be causing a 'step'?

[Pete39]

You say you've had this setup for 5 years. Have you always had this problem?

As you say, you haven't weighed the dose in the pf. Check this first - ie, are you getting consistent doses from shot to shot?

[timdimdom]

also, considering you only recently went black with your coffee, have you been able to get a consistently good ristretto in the past?
any change in beans since?
have you tried measuring the temp of water coming out of the junior?

[Stickleback]

Hi Journeyman

The ristretto is generally bitter and thin, and the pour usually similar. It can look quote nice as well, and the taste sites improve, but at no stage is it a decent pour, other than by pure luck.

[Stickleback]

The water comes out well without a basket too.
Loads of steps with the grinder. I upgraded from a 480 and noticed a big difference at the time.

[Stickleback]

Hi Pete

I never really drank ristretto regularly early on, so I can't honestly say that my pour was anyways spot on, but I don't remember it ever being so inconsistent. Certainly I have only begun to swear at my machines over the last year or so....

[artman]

Is your brew pressure ok? Is it rotary pump? If your pressure is high it will really affect your consistency. Also don't forget a decent cooling flush, these machines run quite hot.

Cheers

[Pete39]

Don't worry about "spot on", because as you say, you've just started drinking straight shots - you just want consistency first. I would really concentrate on dose first. If you have a constant dose and the shot weight keeps changing from shot to shot, then you start searching for other problems. Really good grinders are really easy to use because they give a consistent grind and dose. I found with the sunbeam and breville I used, the dose varied quite a bit (by about a gram or more). The breville was a bit better. Once I sorted ways to get a pretty consistent dose, things got much easier (and convinced me that tamping pressure makes almost no difference at all).

[Stickleback]

Thanks Artman
Yep, always do cooling flushes. As to the brew pressure, my gauge shows 1.1 bar at rest and goes down to about 1 during a shot. I'm not even sure if that's high or low!

Weighing the coffee both pre and post grind is now giving some consistency. It's still not a great taste as yet, but it is better and much more consistent again. It feels like I'm walking a tightrope though - one tiny bit one way or the other and -_- Is that normal? Obviously drinking milk based drinks can hide a multitude of sins....

[Stickleback]

Oh, It's an older vibe pump too - a bit noisy, but that has remained the same over the years.

[flynnaus]

There are lots of things to try. I don't think it's your tamper. Are you making a single shot as a doppio ristretto or are you pouring two shots from a double basket?

Haveyou considered it might be your coffee? Milk can mask a few 'defects'. What do you usually drink and how do you roast it? How long do you let it rest before drinking?
Try a bean that is known for producing good creamy pours with lots of body. The KJM blend is a good candidate.
You might also need a benchmark. I would consider buying a bag of premium coffee and trying that out. Alternatively, do you know someone who doesn't mind black coffee and could give your coffee a try and an opinion?

[Journeyman]

I think tamping, for a given method, is a fine tuner for a shot. But tamping method can make a big difference.

Something to try... I found it made a hell of a difference to my consistency in shots. Progressive tamping is a way to remove the tamping differences from the issue. By tamping lightly every couple of mm's, you get a more consistent pressure profile through the puck. Heavy and single tamp tends to give a high pressure surface and almost no pressure at the bottom of the basket.

So try checking your grind by hand and then progressive tamp it using about a 3kg tamp at least 3 times through the grind process. I find 3kg is MUCH easier to guesstimate than more than 15kg and is much easier on the wrist as well.

By check manually I mean, grind some and then take a pinch and squeeze it between thumb and finger. Remove finger and look. If you can see your fingerprint, it is too fine. If the mini-'puck' breaks apart instantly into a wad of crumbs, it's too coarse. You want a compressed mini-'puck' with maybe a couple of cracks in it, but most of it should hold together.

Next, 'smear' the puck - rub your finger across it as if to brush it off your thumb. You should get most of the grinds gone but still have some fines in the print ridges.

Once you have that, grind enough into the basket to make sure the tamper will compress it. (baskets with a taper might need several mm's before you can get an unbroken surface) Tamp lightly and polish. Repeat until you have the dose where you want it. A good starting point is to grind the weight the basket is rated at if you know it. Otherwise a double of 15g - 16g should do fine. Try doing a nutating tamp for the last one - roll your wrist to make the tamper compress all the way round the edge. Gently!

None of the tamps should be more than 3kg. The final product should be well down from the rim of the basket - both my SB's and my VST's perform best with the grind about 4mm - 5mm down. At that level the 5c test doesn't even register.

Now pour your shot. I've also found on my EM6910 machine that starting the shot till the 1st drip then stopping it and starting it again often gives me a richer shot. YMMV so try it with or without the faked pre-infusion method.

Let us know what kind of shot you get...

[Journeyman]

Also, milk hides sins but not pours. If your pours looked OK before but now look wrong, that's not milk.