Psyd wrote:I never intended to imply (and I'm sorry if anyone took it that way) that you shouldn't adjust all the issues that you're aware need changing.

Again, this presumes (as you say) that "you" (that is, whoever is pulling the shots) is aware of WHAT needs changing. And that is a completely different scenario than knowing SOMETHING IS OFF, but not being aware of exactly what that something is.

Two completely different scenarios. Jim, given his level of experience and expertise, is much more likely to be aware of what needs changing, be that one, two, or even three different factors that constitute a shot. OTOH, someone with limited experience may know that something is off, but not know exactly what to change. That may be a scenario in which the individual tries various things -- one at a time -- in an attempt to correct the deficiency and improve the quality of the shot.

A complete newbie may not even recognize that anything is off, but that's another issue.

Cheers,
Jason

Q: Change one variable at a time - good advice?

A: Yes . . . and no. As with nearly all things, it depends upon the specific individual -- upon their experience, their knowledge, and their expertise in diagnosing the problem(s).

I recognize now that people may need some simple search strategy when it's not clear what direction to go. This will happen often for newbies, and occasionally for everyone.

Here one variable at a time recommends itself as a heuristic; but even then, it may be better to modify this with a little barista knowledge. It may be better to think in terms of shot characteristics rather than shot variables.

For instance 1, if you cut shots by blonding, a tighter grind will give you slightly longer shot with less volume, rather than a lot longer and the same volume, or a lot less volume for the same time. This is technically a two variable change, but one that keeps the extraction changes proportional. Blonding is the indicator of the true shot characteristic, while time and volume are two strongly interacting variables

For instance 2, if you decide to change the dose, a true shot characteristic, it will also be best to immediately change the grind (finer with a lower dose, coarser with a higher dose) to keep the flow rates roughly constant. It will also be good to change the shot volume proportionately to the dose to keep the concentration constant. Finally, for the ultra-punctilious, it is also a good idea to raise the the temperature for higher doses, and vice versa, so that the average puck temperature remains constant.

The point here is that a true ceterus paribus variation in one key shot characteristic will require known proportionate adjustments in other variables to keep the other shot characteristics the same.

I would have no objection at all if people advise changing one shot characteristic, rather than one variable, at a time, when searching for the best extraction, since this will get people to the better tasting shots with less flailing.

zin1953 wrote:Again, this presumes (as you say) that "you" (that is, whoever is pulling the shots) is aware of WHAT needs changing. And that is a completely different scenario than knowing SOMETHING IS OFF, but not being aware of exactly what that something is.

You're not here for the huntin' are ya, son?
That's pretty much a paraphrase of what I was saying. Read it again slowly, and it will (hopefully) come to you. I'm completely aware that didacticity is a weak point of mine, and that it was probably my fault, but look again with that in mind and see if you don't get that exact jist from that post.

another_jim wrote:For instance 1, if you cut shots by blonding, a tighter grind will give you slightly longer shot with less volume, rather than a lot longer and the same volume, or a lot less volume for the same time. This is technically a two variable change

That starts to get into a bit of semantics, Jim. If you cut by blonding, technically you're abandoning your shot before it's intended volume to avoid the thinner, waterier espresso components (Bad Stuff [tm]).

The point that I was trying to make (and maybe the third time is a charm) is:
If you're not familiar with the effects of changes to your technique, and you're finding flaws in your end-product, changing everything willy-nilly is ludicrous, if you're starting point is the 'golden rule'*. If things aren't working out, and you DON'T KNOW WHY**, try changing one variable at a time*** to see how that effects your shot. If it makes the shot better, keep changing in that direction till it stops making it better, and then start in on another variable. Follow this convention until your shots become acceptable****, and feel free to go back to some, as they are interdependent.


*The 'Golden Rule' is simply a set of variables that is given to those starting out to illicit a shot-group that will get you in the ballpark fairly quickly. Each and every one of these will have machines, coffees, barista technique, and local meteorological variations that will or will not change any of these. Some people get great results ignoring all of them every time.
YMMV, Subject to change without notice, some symptoms are not effected, not responsible for lost or stolen items. etc.

** If you're an expert, and know what variables are off, and which ones need to be adjusted by how much, this does NOT seem to be in your best interest. Do what experts do, and change everything to what it needs to be at the next shot.

***Unless, of course, your the guy described above, or can't justify the physics of adjusting one variable in an interdependent system of variables. Once you've perfected espresso making, feel free to abandon this approach.

**** Once you've perfected espresso making, there is no such thing as 'acceptable'. Each shot can be improved, and even 'godshots' have their downside, in that they're rarely followed by a second.

Of course, I keed....

Psyd wrote:You're not here for the huntin' are ya, son?

I was agreeing with you . . .

zin1953 wrote:I was agreeing with you . . .

Oh..

<Litella>
Nevermind!
</Litella>

Psyd wrote:That starts to get into a bit of semantics, Jim. If you cut by blonding, technically you're abandoning your shot before it's intended volume.

???????

When I change the grind, I change the flow rate of water through the puck. Quite sadly, my intentions, be they about time or volume or whatever, never seem to affect the espresso directly. That is why I never considered them espresso variables. Since your intentions indeed are espresso variables, I now completely understand why changing just one at a time works so well.

another_jim wrote:???????

Semantically, you're referring to the 'variable' as what is happening in the shot. I was referring to the 'variable' as to what is happening with the technique. Semantically, we're using the same term to describe two different, but very similar things. I meant, 'things that you do to make the coffee' when I suggested changing only one at a time.

Language... sucks, hunh? I wish I was better at it.

So now it would appear that we have two different sets - the inputs (AKA "variables") and the outputs (AKA "characteristics"). Modifying one or more inputs will affect one or more outputs.
Inputs (in no particular order):

• bean type(s)
• bean freshness
• shot dose
• basket type
• tamp pressure
• tamper style (really? maybe...)
• starting water temperature
• grind size
• starting machine pressure

Outputs (ditto):

• final shot volume | flow rate
• total shot time (starting at turning on the pump, ending at turning off the pump)
• shot body
• flow color
• crema color
• crema persistance
• flavor intensity

Next question: how, and in what order of significance, do these correlate?

I've re-read malachi's article on understanding espresso, as well as jim's espresso guide. Again, you guys have really done a GoodThing™ (that's Alt + 0153 for the TM superscript) . At this stage in my journey, I'm finding new facets in these articles, and for this I am very appreciative. Thanks, guys.

Can this information be organized in such a manner that the relationships can be more easily defined? (i.e. Output = thin/sour shots. Diagnosis = underextraction. Contributing inputs, in order of effect, are grind and temperature. Shamelessly stolen from Jim's article.)

As I mull this over, it seems more apparent to me that I've been attempting to influence an output by manipulating a single input at a time, without taking into consideration the idea that the output may be influenced by multiple inputs. I've had limited success in this manner, but struggle on. I'd really like to find a map that will help to guide me on this journey.

-s.

Sherman wrote:ONLY then will I start tasting, and based on those taste tests will I begin adjusting temperature first, then updose/downdose.

I taste practically every shot, even if the extraction was clearly off. That way, over time, I learn to recognize minor taste defects in otherwise perfectly acceptable espressos and have a good idea of what went "less right" (at first I wrote ...what went wrong, but in fact, without practice with more obvious taste defects, it's harder to recognize their smaller siblings masked by a good taste profile).