Hi guys..

I've been pondering this idea of reducing the influence of smoke on the beans.

The smokiness in coffee is something that is not completely avoidable simply by the nature of the roasting process.. Or is it?

I think the factors that come into play for how much the smoke from the roasting process influences your beans are:

(not in any particular priority)

+ roast time
+ heat level
+ batch size
+ airflow
+ agitation

There are other more obvious factors that can result in a more smokey /burnt flavor but those factors of the imperfections in the process that actually burn the beans (eg. uneven heat distribution, poor bean uniformity, excessive moisture)...

I'm sure this has been discussed amongst roasters pro or otherwise...

Smoke is a physical particle released from a bean, so if it somehow could be prevented from imparting into the surface of other beans perhaps there would be a theoretically, and technically, a "cleaner" cup outcome.

In order:

• 1. Airflow;
  2. Airflow; and
  3. Airflow.

Rich

. . . and roast degree. Second crack and beyond, more smoke.

It's not like smoking meat. The beans are undergoing rapid, high temperature chemical reactions while in continuous motion, and the direction of gaseous flow is all outward at considerable pressure. The beans are producing the smoke, not absorbing it.

Alan

anything enveloped in smoke will pick up the flavor of it. yes that's smoking. and it applies to coffee also, even if the coffee is producing the smoke. its still a very sticky particle.

No. Basic physical chemistry. The pressure of gasses going out is higher than the pressure of gasses trying to get in. As an experiment, put a test tube of boiling water over a Bunsen burner in a confined but ventilated space and blow a constant supply of smoke into the space for a few minutes. Remove the test tube while still boiling, allow to cool, then check the water for smoke contamination. You won't get any. The pressure of the steam going out of the test tube is greater than the pressure of the smoke trying to get in.

At the temperatures where coffee starts to emit smoke (generally above 205C) stickiness or otherwise is not an issue, you have a large volume of gases trying to get out of the bean rather than clusters of smoke molecules trying to stick to it.

Alan

weebit_nutty wrote:Smoke is a physical particle released from a bean, so if it somehow could be prevented from imparting into the surface of other beans perhaps there would be a theoretically, and technically, a "cleaner" cup outcome.

boar_d_laze wrote: Airflow; Airflow; and Airflow

That was Sivetz's contention -- that air roasting produces a cleaner cup, and also won't cause cancer, etc, etc.

Nobody was ever able to taste the difference in smokiness or cleanliness between different types of roasts; and they are still arguing about coffee and health. Chances are that Alan is right and that these purported differences are a myth.

something like a bee smoker shooting into the trier hole with aromatic wood smoke

Jim,

My comment of "Airflow, Airflow, Airflow" wasn't a reference to Sivetz nor to fluid bed roasting. I didn't think it ambiguous, but it seems it was. Allow me to clarify.

The reference to airflow was an allusion to the fact that if you remove the smoke from the roasting chamber (of -- I'd parochially assumed -- a drum roaster) the smoke won't stick around to flavor the beans. I hadn't considered the fluid bed paradigm. But since you bring it up, removing the smoke from a fluid bed roaster by airflow would, no doubt, also prevent the beans roasted in one from tasting smoky.

In short, as I'm sure Alan will agree, if you don't remove the smoke from the roasting chamber, the beans will taste of it.

Hope this helps,
Rich

I can read; you seem to have the problems with that

Alan's point was that outgassing prevents smoke from adhering to beans, and mine was that this explains why repeated blind cuppings show no difference in roasting atmospheres (see Illy) The taste going from the smokiest Burns unventilated roasters to the most ventilated Sivetz air ones and all steps in between is the same, providing the bean and environmental temperature profiles are the same (see Schenker). You can even air roast in all CO2 or N2 to prevent oxidation, and it's still the same. The outgassing of the beans protects them from the roast chamber atmosphere.

The OPs idea was good, but it has been tested and disproven.