How do you explore the extraction space?

[DavidMLewis]

This is primarily a question for Chris Tacy, although of course anybody's welcome to answer. In various reviews, you speak of varying the basket size, dose, temperature, drink size, and extraction time. Exploring this space with a new coffee seems like a hugely daunting task, particularly for those of us who home-roast and therefore may have at most half a pound of a given blend, with no assurance that the next roast of the same coffee will be exactly the same. Do you have any rules that help you do it? I'm deliberately leaving this open-ended, although I have some vague, weak ideas. Thanks in advance for the help.

Best,
David

[malachi]

Wow.

It's a big topic - and a bit daunting.

To be honest, it's largely trial and error leading to some vague understandings of general rules. I wish I were better at it or it were more scientific.

I tend to follow a pretty clear process and will happily describe this if it will help.

If I have a new coffee I tend to always start with the LM ridged double basket and a target extraction volume of between 1.75 and 2.0 oz.

First I'll establish a brew temp starting point.
I'll evaluate the coffee for two characteristics. First - roast degree and second - bean composition.
With the former, I tend to make some quick rough decisions. If the roast is light, I tend to start with a baseline temp of 202F. If medium, I will stick with 200F. If dark, I'll drop it down to 197F.
Now... I'll also adjust this based on the bean composition. If, for example, I'm working with high-grown washed arabica I'm going to reduce the brew temp. If I'm working with aged or monsooned coffees I will up the brew temp (both from the baseline above).
So a light roasted coffee with monsooned beans will move up to 203F as a starting point.

Once I have a temp starting point I'll establish a dose starting point.
For this I'll look at two aspects - the bean composition again and then the "signature taste."
If the coffee has a lot of naturals or pulped naturals I'll go with a lighter dose. If the coffee is mostly high-grown arabica I'll up the dose.
So, for example, with the Terroir Daterra Reserve I'd go with a 17.5 gram dose. But with the Stumptown Hairbender I'd go with a 20 gram dose.
The "signature taste" is a harder one and requires some knowledge of the roaster. Is the person roasting this coffee a fan of low acidity espresso? Are they a "chocolate bomb" aficionado? If you know what they like out of their espresso you can do minor adjustments to your dose. So, for example, based on this I would actually drop the Terroir Daterra down to a 17 gram dose but would up the Stumptown Hairbender to a 20.5 gram dose.

Once I've got temp and dose I'll start experimenting.
I always start by re-evaluating temp. So I'll pull a shot and evaluate it for brew temp. Is it alkaloid? Is it thin? Is it sour? Astringent? Based on the taste, I will alter the temp by small degrees to find the sweet spot.

Once I've found what I feel is the brew temp sweet spot, I'll start working on dose.
The way I tend to do this is focus on two things. First - clarity of flavour and second - roundness and balance.
If the cup is "muddied" I'll reduce the dose. If the cup isn't fully developed and sweet and rich I'll up the dose.

With many coffees this will get me to the point where I'll have a cup profile I really like.
But there are exceptions. There are times when I won't be able to get to where I want to be with just these factors.
It's usually only at this point that I start looking at changes to extraction volume and basket size.

For example, I've found that some lighter roasted delicate coffees tend to end up poorly developed no matter what I do - especially when they are pulped naturals. But if I then swap to a triple basket and deliberately down-dose (19 grams) I "open up" the coffee and it becomes more defined and clear. Or with monsooned coffee I find that the only way I can get the desired sweetness without getting a "wet cardboard" aftertaste is by going with a triple basket, normal dose and then pulling a ristretto shot.

A lot of the time I'll find a "sweet spot" that I like but then start wondering about what a coffee would taste like when pulled differently.


To be honest... I'm incredibly lucky. Most of the coffee I experiment with is free to me. If I were roasting my own, especially in small batches, I don't know if my approach would work at all. And if I were paying retail... I don't know if I could force myself to throw away so much money.


Ummm... was that at all helpful or clear?

[another_jim]

I follow a simpler process, since I don't experiment with dosing (I'll have to now), but just with temperature and ristretto/normale.

If I'm tasting something bright, like an SO, I start with a high temp ristretto, since I find this the most "comfort food" shot. Generally these come out sweet and undeveloped. I use the Faema basets for these, since I find the LM baskets don't work well for ristrettos (the flow is too even, the Faemas start slow and black, and get faster and lighter, so are easier to use for ristrettos). I generally move to lower temperatures and longer shots at the same time. If the shots aren't sweet enough but bitter, I'll stay ristretto while dropping temp. If I've decided on longer shots, I go to the LM double basket, since these have a clearer flavor and a more uniform extraction for anything near normal size/dose. I don't much like the triple, since the proper dose overflows my 2 ounce cups, and for my taste, they really suck on ristretto shots. Certainly, if ever experiment with lowered doses, I'd certainly use the LM basket, since the faemas seem to work best when overstuffed (there's a smaller 12 gram double, which I haven't quit figured out yet.)

Much of this is based on my habits, what I'm comfortable with, etc. YMMV. It's best to experiment with a fairly mild washed coffee with a bit of complexity both top and bottom, I'd recommend an east african, or oddballs like the blue lintong. These are more consistent pull to pull -- a harar or yemen never tastes the same, even if the shots are identical. Burn through a pound of the coffee trying various temperatures, doses and grinds. That will do it.

I find I usually know how I want to adjust the next shot when I taste this one; but I'm not entirely sure if I've described all the factors -- I tried in the espresso guide -- but by now it's pretty automatic.

[cannonfodder]

You know, I have been trying to absorb everything I can over the past year of my espresso journey. I have read, tried, gotten Zen with and gone uber-techno-geek with equipment and beans. But these two posts are two of the best I have read.

I really wish I could spend a couple of leisure days with a professional barista just having a leisurely discussion about the tricks of the trade and sampling espressos prepared in different ways. I often wonder if those few of you that live close to Chris, Dan, Jim, Terry, Mark, (and the list goes on) realize how lucky you actually are. To be able to drive over to Chris's house and have shots from the mother of all home machines or a jam session at Counter Culture, maybe one day.

For now, I read, roast and try. And thanks to the support and knowledge of places like HB and CG, my knowledge base is increasing, my shots are 100% better than any commercial cafe in Ohio and my journey continues...

[malachi]

It's a really humbling process.

I've given up trying to guess what the correct combinations are going to be - I've given up thinking I know enough to predict how coffees will react. Instead I just try to pay as much attention as possible and keep on tasting and trying.

There are just so, so many variables.
And when I try to wrap my brain about the inter-related dependencies - the effects and implications of changes to variables on other variables... It gets overwhelming really fast.

So I try to limit variables as much as possible and try to never jump to assumptions.


I think at a certain level, this is why I get frustrated sometimes with the focus on gear.
I just feel that, by paying total attention to the flavours in the cup and the results of changes to variables on that cup you can learn so so much more than by focusing on the gear.


And speaking of which - I think I've become distracted by the cool gear aspect of the GS3. I've spent more time measuring temp than tasting a single coffee under various conditions. Enough - time to get back to what matters... the coffee.

David - thanks for starting this thread.
Jim - thanks for sharing your insight.
and Dave... thanks for re-inspiring me.

[another_jim]

So, with all the baristas and alties dropping by, the tweaking discussions may be worth a thread for themselves. here's what I mean.

I usually have no good idea where to start with a new coffee, but I really fancy myself as being able to taste a shot and come up with how to tweak it next time. Of course, I've never really tested my skills by doing it with a bunch of other people. So I was wondering if all you guys were agreeing on the "next tweak" for a given blend, or whether you ll came up with different ideas. Is it "great minds think alike" or "too many cooks spoil the broth?" With a wonderfully tweakable machine like the GS3, it would be fun to get an idea of the process. and arguments, if any.

[malachi]

Unfortunately, I didn't really structure it that way and instead blew through a bunch of different coffees (rather than focusing on tweaking one towards perfection).

In retrospect - this was a mistake and a good illustration of what I mean when I say I let my inner-geek take over too much.

[Walter]

You know, I have been trying to absorb everything I can over the past year of my espresso journey. I have read, tried, gotten Zen with and gone uber-techno-geek with equipment and beans. But these two posts are two of the best I have read.

I really wish I could spend a couple of leisure days with a professional barista just having a leisurely discussion about the tricks of the trade and sampling espressos prepared in different ways. I often wonder if those few of you that live close to Chris, Dan, Jim, Terry, Mark, (and the list goes on) realize how lucky you actually are. To be able to drive over to Chris's house and have shots from the mother of all home machines or a jam session at Counter Culture, maybe one day.

For now, I read, roast and try. And thanks to the support and knowledge of places like HB and CG, my knowledge base is increasing, my shots are 100% better than any commercial cafe in Ohio and my journey continues...

I can only second that...

Thanks Chris & Jim!

[cannonfodder]

I have noticed that there tends to be two distinct trains of thought in the espresso world.

You have the technical geeks. The nuts and bolts (science) behind the process. Measurements, tests, and technology used to dissect the process, to learn exactly what a change in one of the dozens of variables will result in. Then use modern tech to minimize those variations (thermocouples, PID's, regulators, etc).

The second school of thought is the art of espresso. Don't worry about the nuts and bolts, it is what is on the other side of the portafilter that makes the difference. The Zen aspect, pulling shots by feel and frothing milk by sound and touch. No gauges, no measurements, pure instinct that has been developed by years of practice.

There is nothing wrong with either of these beliefs, nor do I believe that one can exist without the other. In order to maximize what you have in the cup, you need to understand the mechanics behind the process as well as poses a certain amount of intuition. Science meets art, or the GS3 meets the manual lever.

So chin up and push on with the tests and measurements because they are needed. They validate and prove the integrity and abilities of the machine. Then your experience, the art, of espresso is enhanced by the science of espresso. In the end you are rewarded with an ever increasing quality in the cup.

[malachi]

So... how about those of us who feel that it's all important, but that the goal is actually understanding what is going on?


An example... everyone seems to have decided that flat line temp stability is "required" for good espresso. This is not based on a scientific process or on observation (IMHO). It is "unguided science." We have not bothered to taste and evaluate the results of various brew temp profiles in a structured and scientific manner.

The trouble is that you should measure as part of a planned process designed to evaluate - to prove or disprove an observation.

Without tasting - without that evaluation of the end product it's all just a form of intellectual masturbation.


So - where do those of us who value measurement and value the scientific method but understand that in the end it's what's in the cup that matters and that is what should drive scientific exploration fit?

I think the problem is always on the handle side of the portafilter.
But I spend a huge amount of time trying to understand, measure and control variables.

Where do I fit in?

[barry]

An example... everyone seems to have decided that flat line temp stability is "required" for good espresso.

okay, i'll stand up and wave my hand: i do not agree with that "requirement".

So - where do those of us who value measurement and value the scientific method but understand that in the end it's what's in the cup that matters and that is what should drive scientific exploration fit?

to defend against both the dogmas of technification and the myths of tradition.

[malachi]

to defend against both the dogmas of technification and the myths of tradition.

LOVE it!

[cannonfodder]

So... how about those of us who feel that it's all important, but that the goal is actually understanding what is going on?

Where do I fit in?

But that is the trick. Learning the variables (science side) and being able to marry that to the resulting cup (art side). In my mind, achieving symmetry between the two is the holy grail of knowledge.

My observations were not aimed at any one person, just a general observation over the past year based on my observations of post in multiple forums. You and a handful of others have found that balance, as evident in you first post. Knowing that adding a gram here or subtracting a degree there will typically yield Z in the cup. Keeping track of all the deltas involved is mind numbing at times. That is where experience, art and science meet in the cup. Without understanding one, you will never master the other.

And with that I must shut down and head off to bed. I am standing here in my smoke filled garage at 1:30am, covered with chaff and looking at six different beans and a notebook with scribbling that only a another coffee enthusiast would understand. I am getting there, slowly but surely, and one day I will hopefully hit that balance.

[another_jim]

I have noticed that there tends to be two distinct trains of thought in the espresso world..

I certainly don't hold the record on being umber-technical, but I do a lot of quasi-technical experiments. My rule is that the experiment has to end in a taste test. If I try a machine or roasting modification, I usually am less interested in characterizing the change in machine performance precisely (OK, I also don't have the test equipment and construction know-how for that). But I think as long as technical improvements or experiments don't end with a tasting report, they are incomplete.

On the other hand, some people are more comfortable doing the tasting, others the modding; so there's no reason these two parts of the same process shouldn't be done by different people.

Pursuing understanding is a much more difficult and noble goal. My approach, when successful, ends up with recipes that work, "if you want your coffee or shot to taste like this, do that." But working recipes are only the first step to understanding coffee; after that one has to figure out why they work -- a lot tougher.

For instance, a recipe that works fairly reliably (not 100% of course, but I'd guess 80%) is if the shot is sour, go hotter, if bitter go cooler. I think this also works for brewing -- I certainly find lighter roasted, bright centrals more balanced brewed relatively hot than relatively cool. However, to find out the how and why is beyond my powers. Such hows and whys would lead to new techniques and insights -- something that recipes cannot provide.

Still, for now, I'll gladly settle for lots of reliable recipes.

[rcs914]

to defend against both the dogmas of technification and the myths of tradition.

That is great Barry!



You know, I've been seriously interested in coffee and espresso for a little over three years now. The one thing I've learned is that the more I test, the more I experiment, the more I play around with with it all, the less I feel like I really know, since every aspect seems to just create more questions. The idea seems reasonably simple at first. Fresh coffee + Proper grind + Proper water temp (whatever that may be) = decent espresso. It's only after a while that one really comes to appreciate the intricacy of the whole process, and how, as Chris said, there are SO MANY variables.

While I feel that the technical aspect is a tool for understanding, I will readily admit that eventually I get overwhelmed by it all, such as when I am looking at charts and graphs of long term temperature studies. While I think that knowing these things can be helpful, sometimes it just seems so far removed from the point of the whole exercise, which is to enjoy the coffee (yes, I know that isn't a new sentiment ) This isn't to say that I would be adverse to doing the same thing to my own equipment, to further my knowledge about how it works, but I've been limited by how much I'm willing to spend on said test equipment.

I think this is where the appeal of machines like the GS3 come in. They eliminate, or at least help you control in a repeatable fashion, some of the multitude of variables. Machines like this are technical wonders, but you still have to have a reasonable knowledge of what you are doing "on the handle side of the portafilter". Personally I think that the biggest benefit to a machine like that to the home user is to be able to readily get good (if not absolutely mindboggling) espresso on a routine basis, WITHOUT having to worry about exactly what your intra-shot temp profile looks like, or having to flush 6oz of water, and counting off 14 seconds before starting the extraction. You can adjust the temp to your liking, and pretty much get a pretty dang good shot, as long as you take some care with grinding, dosing, tamping, etc. This isn't always so easy when trying to flush a HX to the exact temp you want.

I don't mean to make it sound like these machines enable the user to be lazy, because they don't. Personally I see the benefit as allowing the user to simply get the most out of their coffee, without having quite as many sink shots. Even the "mediocre" shots are likely to be significantly better than the same non-professional user would get out of a Gaggia Coffee, simply due to greater control of certain variables.

Anyway, sorry this rambled a bit. I was writing it over several hours while I was at work.

Chris

[Walter]

As a - once learned - chemist, scientist and technician I tend to think that the process of brewing a cup of gourmet espresso is still far too complex for being well understood. And I am afraid it will remain so for quite a while. That the quality of the ingredients limits the quality in the cup is common sense. And for the processes which lead us from the ingredients - water and beans - to the cup we are IMHO by now only slowly beginning to develop a little scientific understanding of some certain parts. Nothing more, nothing less.

Even when we look only at the extraction-process we have a very complex situation. Thus, to maintain that it all boils down to a linear temperature- and pressure- profile means, to say the least, missing the point. By now the physics IMO is understood only to some degree and the chemistry barely at all.

And because of this complexity human experience - of an excellent barista like Chris, e.g. - outperforms technology by far. The intuitive part of his understanding together with the rational part is what enables him to to adapt within a relatively short time to beans and machines and get the best out of a given "setup". Currently I see no way that an automated process could replace that experience.

Of course some measurements - or at least some processing standards - are necessary in order to gain more understanding and the ability get reproducibly good results. But what I do seem to notice is a rather narrow focus on temperature and pressure. This is not to say that these are not important, but they are not everything.

Somehow I do compare this with photography, a good camera will help a good photographer to get good results. But the same camera in the hands of another one may produce rather poor results. Whereas a good photographer may get even spectacular good results with an average camera. And this comparison - or allegory or metaphor, if you will - also tells me at what to focus and at what not: I will not focus on tools and toys and techniques to examine the quality of my cam, rather I will try to develop the "eye" for a good picture and the necessary techniques to achieve a good result. IMHO and especially for the home-barista it is as simple as that...

----

And as a sidenote: Chris' description above probably has already helped me within two days to get the best cup of an Ethiopian Bonga Forest I'd ever had.

[cannonfodder]

Without challenging the currently accepted 'norm' there will be no continued evolution. As I look back at the history of espresso (or anything else), every milestone was created by one person that asked one simple question, is the there nothing more?

In each case, the technology and cup were thought to be at the zenith, there is no way to improve upon what we currently have. Then someone thinking outside of the box questions the established dogma. Applying a bit of new technology to the old art suddenly yields the next big breakthrough. In a hundred years people may look back and wonder how we ever made due with the GS3 and its low tech PID controllers and rotary pump. We have not even touched on the source, the Arabica tree. Maybe the next big innovation will come from the field and not the lab.

Using technology to enhance the understanding of the art of espresso. Learning to balance the two is the trick IMHO and is what I am targeting. I believe the best baristas have a solid understand of both. As I said, without understanding one, we will never master the other.

[malachi]

I think that the next big innovation will come at the producer level.

At least I certainly hope it will.

[barry]

While I feel that the technical aspect is a tool for understanding, I will readily admit that eventually I get overwhelmed by it all, such as when I am looking at charts and graphs of long term temperature studies.

oh, chris, why would anything like this be overwhelming??

[rcs914]

Hey wait a second, I know that piece!



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Chris