another_jim wrote:both more lungo extractions and cooler temperatures tend towards acidity, while both more ristretto extractions and higher temperatures tend towards bitterness.

Can you elaborate? I agree on the temperatures, but I would have said the opposite on ristretto vs lungo.

another_jim wrote:And that brings us to the far more interesting topic of dependent variables, the taste of the shot, and they relate to the independent ones.

• The aromatics and olfactory aspects of the taste are determined by the coffee, and nothing else - whirly blade and WBC shots will smell about the same, if the coffee is the same.
• The tongue taste balance has two variables true of all brewing, the coffee/water ratio or the coffees strength, and the degree of solubles extraction or roughly the balance of sours (underextracted) to bitters (overextracted). You don't need five different extraction variables (dose, grind, temperature, pressure and shot time) to manipulate these.
• Finally, in espresso shots, it is possible to bias of the balance of the sweet comfort food flavors (sugar, honey, caramel, chocolate, etc) versus sours and bitters combined, even at the same solubles extraction and cup strength. This is either because the relative extraction levels can be altered, or because the flavors can be differentially biased by the crema and extracted oils.

This is pretty brilliant, IMHO. In all the pages that I've read on espresso, I'm not aware of anyone who has made a statement like this so succinctly. (And, I might add, with such cojones.)

The part about balancing "comfort" flavors with sours/bitters is the most interesting of the interesting. Aside from buying a new grinder or espresso machine, we need to further develop guidelines about how to go about this. I understand where Chris Tacy is coming from when he says, "There are no rules," but I think that's just a temporary stage. There are rules, we just haven't discovered enough of them yet.

Also, we have to address body in espresso. This is an important sensory quality not simply related to the strength of the espresso.

There's something in espresso that's between body and taste; and it's what's driving us all to this craziness of spending huge sums of money. Here's what I mean.

I can take a fresh roasted batch of Esmeralda, use a simple home grinder (e.g a Solis Maestro or Capresso Infinity) and a French press, and make a cup of coffee better than 95% of the shots I will pull this year. But an espresso shot has structure, you are sipping the liquid through a layer of crema. This translates into a rapid fire sequence of varying flavors and mouth sensations, rather than just the single continuous sensation one gets from most liquids. I'm reviewing a coffee now that when done right has a honey chocolate crema, and blueberry, apricot, flower liquid. There is nothing else on earth that can match the sequence of flavors and sensations like this, and the only place on earth to get it is from a good coffee in a well pulled shot.

The structuring of the espresso shot also explains why some superlative coffees, like the Esmeralda, fail as SOs, while some awful coffees like cheap Brasils or Robustas, which are undrinkable brewed, are pleasant as espresso. The Esmeralda doesn't structure, the cheap Robusta or Brasil does.

Although obvious in hindsight, I've only noticed this taste sequencing recently, as a result of us discussing the limitations in earlier extraction studies, i.e. for me, at least, a good theory that's wrong is better than no theory at all.

The structural aspect of an espresso shot is probably far more complicated to measure or control than the solids extraction or shot concentration. I guess the value of my advice so far is that it deals with controlling the simple aspects of the taste by the simplest means.

another_jim wrote:There's six independent variables in the short run: coffee, dose, grind, temperature profile, pressure profile, and either shot time, volume, or blonding.

Yes, and different variables have different effects. When I approach a new coffee blend, I try to adjust the gross variables first and then fine tune things later:
1. Ensure the coffee is fresh if you bought it roasted. If you roast your own, roast it a few ways, to see which roast brings out the best in the flavor.
2. Start with a standard dose. I use 15 g.
3. Brew and adjust the grind to achieve a proper thickness 25 second extraction or to blonding volumetrically.
4. Fine tune to minimize sour and bitter qualities with different temperatures.
5. If this doesn't work, go back and adjust the dose accordingly.
6. Repeat the process with different degrees of roast (if you roasted your own) and also monitor the flavor progression from day to day to see what the optimum window of opportunity is for this blend.

Adrian

For what it's worth...

I've tuned my approach over time. The old approach (as detailed all over the place) was a good starting point. But some things turned out to be either inefficient or poor at dealing with edge cases.

I try to start with some constants that are as likely as possible to be accurate for the majority of coffees. In this case, I start with an LM ridged double basket and a target volume of between 1.75 and 2.0 oz with a moderate flow rate (somewhere around 25 seconds for that volume though I evaluate by flow not time).

I'll also try and understand the "signature taste" of the coffee.
The "signature taste" requires some knowledge of the roaster's style and the desired flavour profile of the coffee. 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. In many cases (these days) you can use the interwebs to research and find out what the roaster looks for. Otherwise, go by the retail location of the roaster and taste the shots.
This allows me to understand what I'm "shooting for" in the cup.

Once I have this information, I'll start making some guesses on the variables.

My initial goal is to make a quick guess on dose volume.
I do this based upon the coffee (the bean/blend composition.)
If the coffee seems likely to have low pH (has robusta or aged coffees or a lot of naturals) I'll start with a down dose. If it seems likely to have a moderate pH (pulped naturals, a mix of naturals and washed coffees) I'll go with a moderate dose. If the coffee is high pH (mostly high-grown washed arabica) I'll up-dose.
This baseline is then slightly impacted by degree of roast (for a darker roast I'll drop the roast a percentage, for a lighter roast I'll up it).

Once I have a starting point for dose, I'll try to come up with a starting point for brew temp.
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've got temp and dose I dial in the grind and then 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. I'm not looking for a great shot here -- I'm just looking for the right brew temp. The idea is to get the balance of sweet, sour and bitter. If any of these dominate too much, I need to change brew temp.

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. Mouthfeel is one of the critical attributes I'm looking at here - as is sweetness and definition.

This is usually enough. It usually gets me to the point where I have a shot that I feel matches well with the signature profile and optimizes the coffee.
Now... that doesn't mean I like the shot. There are coffees that I just don't like. It means that I feel like I have a cup profile that fits the coffee.

But there are exceptions. There are edge cases where all the above doesn't get me to where I want to be with the coffee.
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. Sometimes I find that some high-grown washed coffees are best pulled very short and slow. The same is true of some Indonesians.
You get the idea.

It's interesting that there's no agreement even on the simple things. Unlike Chris, I up dose low acid, natural processed, low grown coffees, and down dose the high growns. Andy thinks ristrettos balance towards the acidic, lungos towards bitter; I think they balance the other way.

It could be that even these simple things are machine or grinder dependent.

Or personal taste dependent...

Some folks like espresso that tastes like the coffee brewed.
Others like espresso that tastes like the coffee intensified.
Others like espresso that tastes like the coffee smells.
Everyone has their own goal/hope/framework.

another_jim wrote:It's interesting that there's no agreement even on the simple things. Unlike Chris, I up dose low acid, natural processed, low grown coffees, and down dose the high growns. Andy thinks ristrettos balance towards the acidic, lungos towards bitter; I think they balance the other way.

It could be that even these simple things are machine or grinder dependent.

With some thought, we could probably develop a cogent survey of items and use HB members to collect sufficient data. Collecting things like the taste variables mentioned above, the coffees used in relation to those taste perceptions, the machine type and grinder type on which those perceptions are based, and even taste preferences of the subject, (control for years home-brewing, smoking, and other relevant variables) it could be possible to infer whether machine or grinder type (among other variables) play a role.

We would need to identify relevant dimensions to collect; develop survey items to measure each item; put the survey on-line; analyze the data and discuss the results. We have many participants with the expertise to make the development and analysis of something like this work.

Any interest?

Mark

I'd recommend keeping it simple, perhaps use the board's poll utility.

What do you do when the shot is
-- too bitter?
-- too sour?
-- too intense?
-- too flat?
-- not sweet enough?

The possible answers are:
-- dose up or down
-- grind finer or looser, aka flow slower or faster
-- shot volume up or down
-- temperature up or down
-- pressure up or down

Even this comes to five questions with ten possible answers each (not counting combination answers). This may already be too much to get anything useful.

another_jim wrote:It's interesting that there's no agreement even on the simple things. Unlike Chris, I up dose low acid, natural processed, low grown coffees, and down dose the high growns. Andy thinks ristrettos balance towards the acidic, lungos towards bitter; I think they balance the other way.

It could be that even these simple things are machine or grinder dependent.

This is fascinating and confusing. I look to people like Jim, Chris, and Andy for reference-quality espresso science, and I would love to see some debate on these points.

And if machine & grinder differences can inverse certain "laws" of extraction, then I'm going to have to parse advice more carefully.