As a consumer of coffee from several different sources (made at home, from a coffee shop, out of a fancy designer can at a convenience store), I have often wondered about their relative caffeine content; "Does three of these equal two of those?"

To that end I'd like to ask if there are any ways that coffee consumers can measure caffeine content of what they are drinking.

I'm not asking if there are tables out there or ways to look some of them up or estimate the caffeine content of these coffees, I'd like to know if there's any way that a particularly nerdy consumer can measure it themselves, even if it requires a bit of an investment.

I asked this in Chemistry SE many years ago to no avail:

Answers here in Cooking SE don't quite make it:

update: Chemistry SE's What is the standard industrial method for measuring caffeine content in food and drinks? has now been nicely answered; just buy a briefcase-sized HPLC system with a C18 reversed phase column and a UV detector :-)

  • @tripleee thanks! My spell checker didn't flag that even though "caffein" seems to have lost its battle with "caffeine" almost a century ago :-) books.google.com/ngrams/…
    – uhoh
    Nov 14, 2022 at 21:14
  • 1
    You're most welcome; I was slightly hesitant to propose that change - some people have very specific and sometimes loud opinions about their preferred spellings.
    – tripleee
    Nov 15, 2022 at 5:00
  • Unfortunately you can't drink your coffee and measure its caffeine. Extracting the solutes in a pot of coffee is feasible, and one could weigh them. This sort of thing has been discussed recently. Did you want to focus on the expense and time required to do it?
    – hardmath
    Nov 27, 2022 at 15:34
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    This recent Question, How can I figure out how much caffeine is in my cup?, drew a range of responses, many focusing on general estimation rather than measurement, but I'd done a bit of research on quantitative approaches. So maybe I can come up with a post that gives a high-school chemistry take on it.
    – hardmath
    Nov 27, 2022 at 23:24
  • 1
    – luser droog
    Dec 3, 2022 at 5:31

3 Answers 3


It really depends on your budget. You say you are fine with a bit of an investment - how does 2500$ sound?

For that price you can get a Lighttells CA-700 which lets you analyze the caffeine content in your coffee.

It may sound expensive but compared to the other caffeine testing equipment out there it's relatively cheap.

Depending on how far down the coffee rabbit hole you are, you may have heard of James Hoffmann - he recently made a video about exactly what you are trying to achieve.

I'm afraid this is currently the cheapest method to get reliable, repeatable and somewhat precise results in measuring caffeine content.


You can get caffeine testing strips🦯 that you can dip into coffee☕, and they'll give you an idea💡 of how much caffeine is in the brew.

Here's one brand, D+Caf, but there are some others. They look like this:

Caffeine Test Strips

The strips have a couple of lines📏 on them, marked D and C. Decaffeinated beverages will only rise to the D line, caffeinated beverages will rise above it.

You do have the problem of that you're going to have to bust out some science to calibrate this thing yourself—out of the box📦 it will not actually measure the amount of caffeine in a drink, but if you dip it in something that you know has 50mg or 100mg, you can mark repeating lines📏 of that span, to make it a more specific indicator🌡.

  • Thanks! This 2014 comment at the Cooking SE question I link to Test strips are not available anymore. Starbucks probably made sure of that. might still be true; is there any evidence that one can actually purchase "caffeine test trips" in 2022?
    – uhoh
    Dec 9, 2022 at 22:33
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    @uhoh, it appears not. I did a search for tests. I couldn't find anything currently available. This 4 yr old Reddit thread talks about all efforts being shut down: reddit.com/r/conspiracy/comments/ax28ro/…. I verified the links. A few products still show up in online catalogs but are listed as unavailable. Caffeine Cop still has a website, but the order-taking is shut off and they abandoned their trademark 11 yrs ago.
    – fixer1234
    Dec 10, 2022 at 1:17
  • Have you tried those yourself? How repeatable are the results? Jan 25 at 23:18

My experiment began last month. There were several stalled efforts because I couldn't bring myself to sacrifice my freshly brewed espresso to science. Eventually I settled on using Starbucks to prepare the coffee, which does seem to offer perhaps an edge in reproducibility.

My aspiration was to use a minimal amount of equipment. In terms of cost:

  1. 300ml borosilicate beaker ($5.95+tax)

  2. Digital Scale 300 gram Max - 0.01 gram precision ($10.95+tax)

Step 1: Solid-Liquid Extraction

This is the easy step, fancy nomenclature for brewing coffee as usual. The beaker fits easily under my espresso machine:

brewing espresso into beaker

I weighed the beaker empty, then weighed it again after adding ~60ml (two shots) of espresso. (Picture shows my home-brewed double shot just for illustration. A "store bought" Starbucks doppio was used in actual fact.)

Step 2: Dehydration of Extract

This is the tedious step, removing the water from the brewed espresso. I did this as gradually as possible with incremental heating in my 1200w microwave, a few seconds at a time on high followed by blowing over the beaker to remove the water vapor.

As the volume of liquid reduces it is necessary to limit the heating time to mitigate splashes from the boiling of confined solution. The picture shows that even with a couple of dozen repetitions of just a few seconds, splashing within the beaker occurred. Indeed a few drops escaped the beaker and landed on the microwave rotating platter, so a better method of dehydration (freeze drying) would be an attractive alternative. Once the espresso residue was fully dried, I weighed the beaker + dried brown residue.

beaker + dried residue

Step 3: Sublimation of Caffeine

Once the removal of water appears complete, we take the final step of removing the caffeine that remains. The key physical chemistry property of caffeine is that its boiling point (352 °F at atmospheric pressure) is lower than its melting point (441 °F or higher).

I preheated my oven (on bake) to 355 °F and put the beaker with the dried residue of espresso on an aluminum pie pan in the oven (center rack). After a matter of seconds a light gray vapor formed in the beaker. I opened the oven door to allow this vapor to blow away. After repeating this twice the light gray vapor stopped forming, and I removed the beaker to cool for a final weighing.


Step Weight (grams)
empty beaker 112.49
espresso 161.90
dried residue 115.06
sublimated residue 114.87

Conclusion and Notes

The total caffeine present is measured by the difference of the last two weighings, as the weight of caffeine driven out by sublimation. This figure is 0.19 grams or 190 milligrams plus or minus the scale's precision of 0.01 grams (10 milligrams). This agrees roughly with the figure of about 150mg cited by CaffeineInformer for caffeine in a Starbucks doppio espresso.

We mention some sources of experimental error besides the 0.01g precision of the affordable Pocket Scale™ pictured below:

digital scale

One source of error, which would tend to reduce both the final residue and the sublimated caffeine, is splatter from the drying process noted earlier. Another is possible moisture retained after Step 2, which would tend to exaggerate the weight of caffeine by confounding it with water weight. Also the weight of caffeine we want is small in relation to the weight of the beaker, which presents a subtractive cancellation issue.

In an effort to minimize the effect of these errors, I chose a "single vessel" procedure, so that the relatively small size of the experimental sample is not unduly prejudiced by transfers. I plan to repeat the experiment and will update if any discrepancies are observed. In particular after thorough washing the weight of the beaker empty came back to 112.49g.

  • Interesting! Hmm... this might be reliable by itself if the dried residue is a mixture of free caffeine and inert, nonvolatile solids (e.g. granite, neutronium, etc.) but I think you need to plot mass vs temperature first and confirm a plateau specific to caffeine and nothing else. en.wikipedia.org/wiki/Thermogravimetric_analysis and hitachi-hightech.com/file/global/pdf/products/science/appli/ana/… and researchgate.net/publication/…
    – uhoh
    Jan 25 at 5:20
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    Validation of the procedure is relevant. My thoughts are not so much about a mass vs. temperature plot, although I did gauge the removal of water by reaching a plateau well below the sublimation temperature of caffeine, as to condense the vapor from step 3 and check its purity (caffeine). I suspect that the cost of additional equipment could be kept below $100, but I didn't want to mix those details in with my basic process write-up.
    – hardmath
    Jan 27 at 20:04
  • That sounds fun!
    – uhoh
    Jan 27 at 21:13
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    There might be other substances that are driven off at the oven temperature. Also, you have poor control over the temperature when you microwave. Using a water bath at a lower temperature and a drying agent to remove the last of the water might work.
    – Buck Thorn
    Jan 28 at 15:18

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