What's the Chemistry Behind Your Cup of Coffee?

[jim mcnamara]

http://www.ift.org/~/media/Knowledge%20Center/Publications/Books/Samples/IFTPressBook_Coffee_PreviewChapter.pdf

Is an overview of coffee chemical analysis. I biffed a comment the other day about the caloric value of black coffee. So I did some reading. The article is aimed at at Food Technologists in a large part.

The takeaway from my viewpoint is:
1. Coffee has food value and nutrients like niacin and potassium, some kCal per 8 oz cup (~2-4)
2. Small amounts of carbohydrate
3. A huge number of compounds closely related to drying methods, coffee species - C canephora, C arabica, and roasting processes.

And using/not using paper filters during brewing has a big effect on the presence of some compounds, as you might expect. Espresso vs dark roast "normal" coffee was discussed in this regard. There was a section on acrylamide content - acrylamide exposure is some thing that has to come to light recently in terms of carcinogenic effects of the compound. Longer roasting time decreases arylamides, so medium roast coffee has about 25% of the acrylamides found in light roast.

 

[DaveC426913]

I take mine with ice. Is that unhealthy?

 

[Evo]

I read that using paper filters reduces some of the 'bad' stuff. I'm too tired right now to find it, I owe you

 

[jim mcnamara]

Paper removes (adsorption) some volatile oils which apparently influence taste. The only really "bad guys" I saw in the paper were acrylamides. A lot of the other things listed are either not on my "bad-radar" or I don't know enough to comment about them, assuming some are bad. They are listed as sterols and bioactive terpenes. "Bioactive" is a door that swings both ways, FWIW.

 

[jim mcnamara]

Hot brewed coffee has a limited amount of emulsified oils (diterpenes, tannins and phenolic acids), some plant sterols like beta sitosterol). I would guess that a large influx of ice might force them to precipitate. Don't know for sure.

One thing I do know - green coffee bean dust is allergenic. Guy in grad school with me researched coffee DNA, and worked for hours grinding green coffee beans. He now cannot drink coffee or eat anything derived from it. And he is/was a researcher for Nestle - coffee naturally. Apparently lots of people who work in coffee production have the same problem.

 

[analogue]

speaking of coffee, I just happened to be reading
Scientific American, Volume XXXVI., No. 8, February 24, 1877 (gutenberg download)

"Caffeone, the aromatic principle of coffee, may be isolated by distilling 5 or 6 lbs. roasted coffee with water, agitating the aqueous distillate with ether, and afterwards evaporating the ether. It is a brown oil, heavier than water, in which it is only very slightly soluble. An almost imponderable quantity of this essential oil will suffice to aromatize a gallon of water."

I found only one instance of "caffeone" in a site "wordnik" which defines it as the aromatic principle of coffee (same as above).

If you use a French Press, you will not have to pass the oils through paper thus losing some of them.