Inconsistent shots

[billy Barista]

It has been quite a couple of months that its happening. The shot qualities changes everytime, and I mean everytime. I have to literally adjust the grinds and tamping every single time I pull shots as the quality changes everytime. Funny thing is it varies, sometimes under-extracted, sometime over-extracted.

Is it the grinder's problem? espresso machine's problem? or my problem? I just cant get consistent shots without working on it everytime. Please help

[cannonfodder]

I would start by checking the dose. Weigh your basket on a 0.1 gram scale to verify you are getting consistent doses. After that, I would check the tamp, is the tamping pressure the same every time, tamp on a bathroom scale to confirm. After that, I would turn an eye to the grinder. How old are the burrs, what kind of grinder is it, do you grind by dose or dump them in the hopper, do you keep a consistent, or relatively consistent level in the hopper?

[HB]

I have to literally adjust the grinds and tamping every single time I pull shots as the quality changes everytime. Funny thing is it varies, sometimes under-extracted, sometime over-extracted.

A consistent tamp isn't a difficult skill to master. Keep it level, tamp with the same pressure. Practice a few times on a bathroom scale if it helps. Frequent grind adjustments are not necessary, unless we're talking microadjustments of less than a millimeter to tweak it within a gnat's eyelash of perfection. I'm with Dave, something more fundamental is afoot. Problems with dosing and distribution are the two most frequently cited causes of inconsistency.

One other potential issue Dave didn't mention... La Marzoccos pressurize very quickly, which means the margin of error is small. You can add smaller diameter gicleurs to slow the pressurization and thus more tolerance of dose/distribution problems. Your local La Marzocco dealer should be well informed on them (IIRC, the smaller ones are 0.6mm).

[billy Barista]

but generally when you guys pull shots does it varies shot to shot? You guys made a very good point about the grinder. I deep cleaned it today it did make a slight difference. I just wonder whether its the machine's problem as well?

[TimEggers]

Dave and Dan offer great advice. Variation should not be present.

[zin1953]

Tim? "Variation should not be present." Do you mean in the cup? or in one's technique?

[zin1953]

Kevin,

Certainly one needs to make sure the equipment is clean and, as you say, a serious clean of your grinder resulted in a noticeable difference. So, too, will cleaning your machine, I'm sure.

My question to Tim above is for clarification only. Your technique should be as consistent as possible. A lot of the gear I own -- and I suspect many others here -- is only used occasionally . . . eventually. For example:

-- I bought a scale to measure how much coffee I was dosing into my baskets. I found I was significantly updosing on a a machine that doesn't really like updosing. (Ooops!) Now that I know what a 14.0-14.5g dose looks like, I don't need to use my scale with every dose, but I do pull it once every week or two, just to double-check and "keep me honest."

-- Once I bought the thermometer so I could improve my milk steaming and texturing (and achieved that improvement), I don't need to use the thermometer every time to achieve great microfoam.

There will, I am convinced, always be SOME variation in the cup. There are too many variables that can be neither quantified nor controlled. But the more consistent you are in your preparation and technique, the more minor these variations will be and the more consistent your espresso.

Cheers,
Jason

[TimEggers]

Tim? "Variation should not be present." Do you mean in the cup? or in one's technique?

Ideally no variation in either. If technique is consistent then the resulting espresso should be too. Granted we're all human and the human element can add some variation. But again good consistency should be achievable in both cases starting with technique.

There's a difference between making espresso as a coffee batch ages (over the course of week or two) and variation in each back to back shot. Coffees do change gradually with time, but most cases its a predictable steady change and again over the course of several days or a couple of weeks.

Now if I'm in front of my espresso equipment using the same batch of coffee one day and my shots are all over the place I stop and reflect on my technique and what I'm doing. If I know that my technique is consistent (scales and all that) then I begin to look at the machine component. But typically the problems are on the handle side of the portafilter.

[cannonfodder]

Consistency is the key, in both the cup and technique. If you use the same blend, then your dose, tamp, temperature should be consistent. If they are, you drink will be consistent. The wild card is grind. As coffee ages the grind changes, humidity also plays a role and will dictate changes in grind. Sometimes you may need to adjust the grind several times in a day to keep the shot timing consistent, other times it may be once every couple of days. But do not try to change your dose/tamp/etc to compensate, keep all of those variables the same and make tiny grind adjustments to dial in the shot timing. Now to throw in a monkey wrench, different blends will take different doses and temperatures, along with different grind settings, to get the optimum flavor. That is why I recommend using the same coffee when dialing in a machine or learning the art of Barista.

LM's do ramp up pressure pretty quick, as do most rotary pump machines. however, I find the LM's to be pretty darn forgiving at the same time. Many people replace the gicleur (group jet) to slow the infusion rate but I have also pulled, and been served, super drinks from a LM that had no gicleur's installed, no flow restriction other than the flowmeter and puck.

[another_jim]

If this is happening at a cafe, my guess would be that it's time to get new burrs on the grinder. When I was doing the Titan Grinder Project tests, I made very sure to do exactly the same thing every time (weighed doses, matched baskets, sifted grinds, etc etc etc). The big new grinders ran like swiss clocks, the exact same pours over and over. The smaller grinders and the ones with older burrs had a lot more inherent variability.

In home use, burrs never get ultra-old; but in cafe use, they will. If my one year old home burrs were less consistent than the new ones; I'm sure two year old cafe burrs will be all over the map.