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Roasting for Caffeine

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GuyanaCoffeeLover

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Apr 20, 2020
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Also, is there a difference in caffeine content from Arabica beans from different origins? Or is the caffeine content in all Arabica beans the same?
 

Tbone666

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Jul 28, 2019
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Simple answers to simple questions. Yes and Yes it can vary from region to region, though the variance is on a rather negligible scale.

For the highest dose of caffeine; look to robusto beans....they don’t taste as good as arabica but can have up to 3x more caffeine.
 
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Mr.Peaberry

Member
Aug 7, 2013
889
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Is it true the lighter the roast, the more caffeine content the light roasted beans will retain?

This is a popular misconception that I had thought was the truth for a long time. I know that studies have been done that seem to suggest that some caffeine is lost during the roasting process, but nothing that suggests that the amount is great enough to have any physiological impact in the consumer. I think the whole thing stems from the fact that caffeine sublimes (solid to gas without going through a liquid phase) at 178 C and melts at 238 C. Because all the caffeine is bound inside the structure of the bean, it can't escape as a gas, except for MAYBE a very small amount. I would expect that if sublimation accounts for any amount of loss, the difference in caffeine content between lighter and darker roasts might be most pronounced using fluid bed roasters where the airflow moving across the surface of the bean essentially blow away any caffeine that has escaped rather than bind to the oils on the surface of the bean. I am not aware that there have been any studies of this in the fluid bed community. Would be interesting to know.
 

Mr.Peaberry

Member
Aug 7, 2013
889
2
Is it true the lighter the roast, the more caffeine content the light roasted beans will retain?

Back to a response to GuyanaCoffeeLover. I found a very good study that outlines the procedure for collecting caffeine samples from coffee beans and determining the amount of caffeine. The final separation of caffeine involves dichloromethane, which emits a toxic gas, and should not be performed without the proper equipment. This is not an experiment someone should do at home. The important thing is keeping in mind that coffee brewing extractions are not laboratory extractions, and will not produce reliable results if one does not recognize that grind size, especially if it isn't controlled well, is going to only add variability into the results obtained. In this experiment the samples were reduced to powder for the extraction.

https://www.ukessays.com/essays/che...tic-error-subimation-of-caffeine.php#citethis
 

Mr.Peaberry

Member
Aug 7, 2013
889
2
Okay...this thread has been cleaned up and reset for discussion. I know from a brief search online that there are many people who feel, have felt, or potentially will feel, predisposed to believing that dark roast coffee has more caffeine that light roast coffee & many others who believe the opposite. The first attempt to carry on a conversation regarding this went down in flames, but I'd like to know if anyone here knows of any really good studies on this issue.

I have my opinion, because the arguments appeal to me. I am looking for a more conclusive basis for my belief, and in the face of overwhelming evidence, will become an advocate of the truth!

What I do know is that running experiments to extract caffeine from R&G coffee would involve, most effectively, dichloromethane, and that is some toxic stuff. This should be done with plenty of ventilation with a blower fan sucking air away from the extraction equipment as from a fume hood.

Another consideration is acknowledging the need for taking the identical mass of green coffee and putting it through the roasting process, and sampling the resulting caffeine content at various degrees of roast. Complications arise from failure to account for the reduction in bean density because of moisture loss. If you grind up the coffee and THEN measure out a weight for light roast and an identical weight for dark roast, your samples are not same because it took more of the dark roasted beans to equal the weight of the light roasted beans. The best experiment would take green beans of uniform size and density. Doing so will provide the best data and is worth the effort. On the back end, the difference in weight due to moisture loss must be accounted for in the samples weighed out for extraction. Other considerations are probably of less effect on the results, in my opinion. So it is my hope to find that elusive data that settles this once and for all....
 
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