There has been some talk of using brewing roasts for espresso, some going so far to say brewed results can be matched in the machine.

For brewing, I roast to just before the end of first crack. Sweetness is intense, aroma vibrant, acidity balanced, body syrupy, with little to no roast flavors. I can easily say my brewed coffee is the best I've had.

For espresso, I roast to just before the beginning of second crack. As espresso, the espresso roasts are, well.... like espresso. Viscous tongue coating body, balancing between acid and bittersweet, tending toward a bittersweet finish. It's what most people would call good espresso.

As espresso, the brewing roasts require a very fine grind and are a different animal altogether in the cup. Heavy, almost dead weight body sitting squarely on the center of the tongue. Acidity in balance with sweetness (no pucker face), aroma intense with the origin flavors loud and clear. The experience is fantastic.... but the body is not the emulsification that in my perception defines espresso.

Obviously I show preferences to the clarity of a brewed roast as espresso. However I'm hung up on the body. Is it possible to get a viscous tongue coating emulsification of coffee oils from a very dense city roasted bean? Is it simply necessary to embrittle the bean with the density/cell structure change that comes from darker roasts in order to make espresso (as defined by being an emulsification) from it?

Asking the question a different way -
What component of coffee is responsible for the body?
How does roast and species/varietal/origin change the body in the cup and why?
A good question.

Thank you, Allon. I appreciate you directing the post towards extracting the core question.

The mouth-feel of espresso seems highly correlated to the degree of emulsification, perhaps even more so than the body of the brewed cup, So I think it's the "why" of espresso emulsification that I'm after.

I may be mistaking my terms.....
http://en.wikipedia.org/wiki/Emulsion
http://en.wikipedia.org/wiki/Suspension_(chemistry)

Whatever form it is and is called, I am talking about that fleeting aspect of espresso mouth-feel. Perhaps the very thing that I'm talking about has notably been called "rubbish" and criticized for its negative flavor qualities.

You didn't specify what you use as beans for espresso. My roasting is similar to yours, not all the way through 1st crack for SO vac pot, and darker for espresso. For espresso, I use 50-60% brasil for mouthfeel or body, taken to the end of 1st crack and 40% central american taken to just at the start of 2nd. You need the brasil for the mouthfeel. Obviously I'm not a big fan of SO espresso, the Don Pachi being an exception.

Marvin

My espresso is 80% Brazil Mogiana pulp natural Yellow Bourbon, 20% Sidama natural, pre-blended, roasted 9min 1st crack at 392F, 13min finish at 445F with a stray crackle or two. I imagine this spells out what the intent is: espresso of universal appeal (yawn).

Espresso extraction emulsifies the oils, and entirely changes the way the liquid coats the tongue. Also the added concentration can affect some flavors more than others.

You can stay close to the flavors of the brewed coffee if you keep the espresso extraction temperatures and shot times at the low end, or do pressure profiling. The NW style ristretto is very far indeed from brewed coffee, and more its own gene of drink. In other words, there are enough options in espresso making technique to accommodate a variety of different relations between brews and shots. The current trend to doing SOs puts a premium on those espresso making techniques that best reproduce the flavors of the brewed coffee; but this would not be true for most blends.

Getting clear, delicious, and in balance flavors from my light roasted single origins isn't the problem; getting the classic espresso mouth-feel is.

The body I'm getting is dense, dark, even runny; there is no crema nor changes in volume over time. The grind is far finer in order to get 20sec minimum. Like I said in the first post, the flavors are preferred to the boring espresso blend/roast.

What's going on? What's the difference? I don't want a response like "you need to roast them darker" or "you gotta have the Brazils"...I want the why of the matter.

FYI: K-10, GB5, VST, 18g in, 30g out, 93C, ~25sec.

Given that coffee roasted to maximize flavor clarity does not produce a beverage resembling espresso (given standard dose, temperature, pressure, time, yield), what can be done besides accepting that crema laden espresso only comes from overly roasted coffee?

In other words, what is missing from a Nordic roast that a Vienna roast has in spades?
Carbonized cellulose?
Caramelized sugars?
Cellular shape/size?

Is it possible to get great body without degrading flavor?