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Flavor going out with the exhaust?
oldgrumpus
Top  #1 Print Post
Posted on 12/08/2023 9:00 PM
Just curious about this. Since heating the beans releases the volatile compounds quickly, I'm wondering if much of the coffee flavors are getting sent out with the exhaust on a gas fired or fluid bed roaster. Does anyone know? The exhaust stream sure smells good!
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
Build thread https://homeroast...post_38189
 
renatoa
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Posted on 12/09/2023 3:07 PM
Why only on those, and not for any other type of roaster ?
Some airflow is mandatory for a well designed machine...
 
oldgrumpus
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Posted on 12/09/2023 11:08 PM
I didn't mean to exclude any other type of roaster, and yes, I agree that there needs to be some airflow, but the question remains...

How much of the flavor goes out the exhaust?
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
Build thread https://homeroast...post_38189
 
renatoa
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Posted on 12/10/2023 3:28 AM
Is hard to quantify/measure such amount of ... flavorware smile

Not even sure after what to sense... like the "smells good" part... none of my neighbors (block of flats) are aware that I am roasting coffee at home, because the smells in my home during and after roast simply aren't of roasted coffee... rather backing bread.
Probably oily roasts. with lot of smoke, are smelling "as fresh roasted coffee", but not my case... the flavors develops in the bag, after cooling.

Sure, in a pro roastery, even a small one (5kg), if all exhaust fittings are well done, my nose can sense the coffee smell, but rather coming from the pile of tin barrels where already roasted coffee stay for days at rest ... and their valve let escape small amounts of divine smell.
But still, the overall smell of the roastery itself is less than what I perceive released by grinding a single dose of roasted coffee.

Others noses perception may vary smile
 
Piotrkurak
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Posted on 12/13/2023 9:34 AM

Quote

oldgrumpus wrote:

I didn't mean to exclude any other type of roaster, and yes, I agree that there needs to be some airflow, but the question remains...

How much of the flavor goes out the exhaust?


Less than the amount of water vapor by roasting. If you collected all the vapor and had really accurate ways to measure the amounts of "contamination" of the water sample you probably wouldn't see much perhaps a percent of a percent.

454 grams times an arbitrary 12% is 55 grams water or just under 2 Us ounces. Somewhere in that sample is a diffusion of aromatics, probably an oil base. Perhaps just a drop because you won't see it. That's the lost aromas. It is however at a lower threshold than you can taste, but high enough to smell.

How much roasting do you do before you clean the "flavor" off the exhaust stack? How did it taste?
Edited by Piotrkurak on 12/13/2023 9:49 AM
 
oldgrumpus
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Posted on 12/16/2023 10:57 PM
Good points Piotrkurak. I think you are correct about the quantity or percent going out the exhaust, but it is speculative. I realize that speculation is all we can do.

Regarding the percent, I'd like to add that although small, it could potentially be a very potent amount of flavor vs. volume. For example, peppermint oil, even in the smallest quantity is enough to stimulate taste buds in a maximal way.
 
Piotrkurak
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Posted on 12/17/2023 10:09 AM
Hence my suggestion for scraping it off the exhaust stack with maybe a solvent like alcohol. Be advised that it is very bitter and in my opinion burnt. Ask me how I know......
 
oldgrumpus
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Posted on 12/20/2023 5:00 PM

Quote

Piotrkurak wrote:
Ask me how I know......


OK! Tell us! I think we probably know. :-)

But one must admit that just after coffee is roasted, it smells really good, and after a while, it looses something. I do know much or most of that is due to chemical reactions, but that isn't my point. My point is that so little of that "smell" is created by a very minute amount of volatile material.
 
Piotrkurak
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Posted on 12/21/2023 9:39 AM
Well I used ethyl alcohol to clean. Nice clear brown coloration in the solvent pot after rinsing the cleaning pad, does a good job removing residuals, not toxic, evaporates with no cleaner residue. Applied tongue to cleaning pad before rinsing. After terrible shock from alcohol, got worse shock from residue with lingering aftertaste. YMMV but it was yuck.
Ever taste a burnt bean? Like that. Suspect the oils in the stack are low temperature volatiles exceeding their oxidation temperature.

However feel free to dispute my findings. Afaik, some people like Starbucks plain black.
 
oldgrumpus
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Posted on 12/21/2023 6:17 PM
I love your sense of humor! I wouldn’t challenge your findings because I probably would come to the same conclusion. But tasting what’s in the stack would be much like scraping carbon from a bbq grill. No reason to think it would taste good.
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
Build thread https://homeroast...post_38189
 
Piotrkurak
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Posted on 12/22/2023 10:01 AM

Quote

oldgrumpus wrote:
. But tasting what’s in the stack would be much like scraping carbon from a bbq grill. No reason to think it would taste good.


["Aye, there's the rub"] you have captured the essence of the problem. Just because it has a pleasant odor, does not mean it is tasty. Room freshener oil has a similar conumdrum. Cinnamon orange room freshener, no matter how appealing to the nose, tastes disgusting. Even supposedly organic derived

In another forum I have a comment: Been doing stupid stuff since 1963 so that you don't have to.
 
oldgrumpus
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Posted on 12/22/2023 1:27 PM
Ahhh. OK. Now I see. Great point. The one about the flavors, I mean.

Regarding the stupid stuff, I've got a long list of them, so you're not alone. :-)
 
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