How much caffeine there is in X coffee?

Caffeine Content in beans and blends

(Source: Newsletter--Mountanos Bros. Coffee Co., San Francisco)

Brazil Bourbons  1.20%
Celebes Kalossi  1.22
Colombia Excelso  1.37
Colombia Supremo  1.37
Ethiopian Harrar-Moka  1.13
Guatemala Antigua  1.32
Indian Mysore  1.37
Jamaican Blue Mtn/Wallensford Estate  1.24
Java Estate Kuyumas  1.20
Kenya AA  1.36
Kona Extra Prime  1.32
Mexico Pluma Altura  1.17
Mocha Mattari (Yemen)  1.01
New Guinea  1.30
Panama Organic  1.34
Sumatra Mandheling-Lintong  1.30
Tanzania Peaberry  1.42
Zimbabwe  1.10

Colombia Supremo Dark  1.37%
Espresso Roast  1.32
French Roast  1.22
Vienna Roast  1.27
Mocha-Java  1.17

DECAFS--all @ .02% with Swiss Water Process

These numbers may be correct for the coffee offered by Mountanos Bros. Coffee Co. but they probably are not necesarily correct in a generic way. Caffeine will vary from farm to farm and plant variety to plant variety.

As a general rule robusta has approximately twice as much caffeine as arabica.


speculative meaning of the % unit

I speculate that X % does mean (as Graeme mentioned before) X g pure caffeine/100 g coffee bean.  Percentages do not have units because the same unit on the top and the bottom of the fraction gets cancelled.  However, this % unit could be more specific: X % pure caffeine/coffee bean.
Lil and K cupper both mentioned volume in various units--(fluid) ounces, mL, cup.  The volume of water, I would believe, has less to do with the final amount of caffeine extracted, and more to do with the final concentration of caffeine in the brew.
For example, I can extract 14 g of coffee beans containing 1.37% caffeine with either 9 oz or 18 oz or water.  Both would give me roughly 191.8 mg caffeine:
(14 g coffee bean x 1.37 g caffeine)/100 g coffee bean x 1000 mg/1 g = 191.8 mg
As you can see from above, the amount of water never enters the equation on how to calculate how much caffeine I have in the final brew (assuming most of the caffeine is extracted in the first 9 oz of water).  But water goes into the equation to figure out concentration.  The one with more water will just be twice as dilute:
191.8 mg/9 oz = 21.3 mg/oz, 191.8g/18 oz = 10.7 mg/oz
In summary, it's not the amount of water used to extract from the coffee beans that determines how much caffeine is in the brew, but only how many grams of coffee beans are used in the first place.  Thus, grams is the only unit of measure that would be helpful, not ounces, mL, cup or anything to do with volume.

Please Translate

This would be a hugely informative list if it were translated to mg per fluid ounce.

Mountanos Bros. listting of caffeine content.

The list you furnish from Mountanos Bros. claims 1.01 to 1.42 caffeine in their coffees. The question was asked as to what the units were, and one person responded they were percentages. Elsewhere, you list a brewing recommendation by the SCAA as 10g coffee in 6 oz water, resulting in 5.33 oz brewed coffee. Taking those numbers as typical, if the Mountanos Bros. list indicated % caffeine in the bean, we would have 10g coffee with 1.01% caffeine (101 mg), up to 1.42% caffeine (142 mg) in a 5.33 oz cup of coffee. If the results indicated % caffeine in the finished coffee, figuring 1 oz water as 30 grams (160 g water in a 5.33 oz cup), we would have 1616 to 2272 mg, respectively. From what you post here, and in other sources I've read, 101 to 142 mg sounds in the ballpark for a cup of coffee; 1616 to 2272 mg looks way out of bounds. Wikipedia notes that the LD50 for humans is in the range of 150-200 mg per kg body weight—about 12,000 mg for a 180 pound person; in other words, about 84-6 oz cups by the first reckoning (percent caffeine in the bean), and about 5 cups by the second (percent caffeine in the cup). Seems that % caffeine in the bean is the meaning of the Mountanos Bros. list.

RE: Mountanos Bros. listting of caffeine content.

100-150 mg of caffeine is the right range for properly brewed coffee with coffee containing a fair amount of robusta pushing into the 200 mg range.

How much caffeine in coffee vs. espresso?

You realize of course that those numbers are totally useless without putting what units in what quantities you mean. Is that 1.37 Grams per ounce? mg. per cup, what size of cup? That could be grains per bagful for all we know. Please find the measurements and add to yor page. It would be greatly appreciated.

RE: How much caffeine in coffee vs. espresso?

You make a good point. I don't have the original source so I can't see what info was in the source. This does kind of make this section less useful for
anything outside of a comparison of varietal vs varietal and as I
stated in the article I'm not really sure how accurate it is even for

how much caffeine in coffee vs. espresso?

I see that the numbers have "%" sign after it,, so does that mean mg. per ml.? I've usually seen it expressed as mg. in a cup, ether 8 oz. or 6 oz.(can you believe this used to be the typical size of a coffee cup, lol.

RE:how much caffeine in coffee vs. espresso?

could be but I don't want to speculate.

It's a percentage,

It's a percentage, percentages don't have units. As caffeine is a solid, the figure would be percentage by weight. ie 1.37% = 1.37g of caffeine per 100g of coffee

I don't think that is right.

I don't think that is right. It could be weight percent. It would not correlate to making 100 g of coffee.

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