amount of caffeine

askthecoffeeguy

You'd get more caffeine from a single basket because its a longer pour and caffeine content is accumulative - its like smoking a cigarette, the more you smoke the more nicotine buil up you get same with caffeine! pat

psaigh

Not sure I agree with you there pat. Around 10 or so months ago I shot James Hoffman an email asking a question of a similar nature. Now I should point out that I don't hold James Hoffman as a reliable authority on caffiene just because he's the current World Barista Champion, but I do (IMO) hold him as a reliable authority based on the ammount of time he spends in a lab and researching all facets about coffee. Based on his response, and my own research, I beleive the following: caffeine is soluable in H20 at 76C and highly soluable at any temp over 90C. Pressure has little to do with it's absorbtion rate but steep time does effect it dramatically, which is why espresso has significantly less caffeine than other brewed methods. French press coffee, which has a steep time of around 4 min's usually absorbs around 96-98% of the caffeine from the beans. Espresso (with a contact time of around 30seconds) extracts around 90% of the caffeine. A ristretto (with less contact time) extracts around 80% of the caffeine. Now, aribica beans typically contain around 1% caffeine and robusta beans typically contain around 2% of their green bean weight. So therefor the maximine content extracted from 8 grams of coffee (I'm assuming 8 grams for a single baskets, some may use more or less) is 80mg of caffeine. Now if the above figures are true (and I beleive they are), one 30 ml shot of coffee extracted from 8 grams of coffee in 30seconds will yeild 72mg of caffeine (8grams*.01=80mg of caffeine; 80*.9=72mg of caffeine). Now a double ristretto, made by extracting 30mls from 18grams of coffee in, say, 20 seconds, would contain 144mg of caffeine (18g*.01=180mg of caffeine total; 180*.8=144mg of caffeine after extaction). It's all to do with total caffeine (which is relative to the ammount of coffee used) multiplied by the percentage at which is absorbed (which is relative to the steep time used, and at what temp). Now if they were to have the same ammount of caffeine from double the ammount of coffee used, the absorbtion percentage of a double shot pulled half way would have to be 40% (180mg*.4=72mg of caffeine) or even less if the single was beleived to have more caffeine, which I personally don't beleive is viable.

psaigh

Now I should point out that I've debated this with countless people of whose oppinions I very much respect, and they are still not convinced. And I for one am happy to be proven wrong if someone can provide me with definitive proof, as I'm not 100% convinced either way.

blanyon

What we need is someone who knows how to measure the caffeine in an espresso and then pull some shots with single basket, double, ristretto etc and take this from the relms of forum debate to fact. Any takers I have a mobile van if you have the technology.

psaigh

What we need is someone who knows how to measure the caffeine in an espresso and then pull some shots with single basket, double, ristretto etc and take this from the relms of forum debate to fact.

Precisely!!

askthecoffeeguy

I'm sure that the results are on the board in terms of caffeine content being tried and tested numerous times, and an intrepid web surfer would be sure to find them Still, hats off to anyone who's willing or able to replicate these results through testing them themselves I still reckon though, and I don't have documented evidence to back me up - but common sense would seem to suggest that a 30ml pour from a single extraction is going to contain more caffeine than a 30ml pour from a double extraction Why? Because with the single the contents are under greater pressure, as there is only one outlet point, meaning a longer saturation time - which, to my mind at least means more caffeine When you extract the same amount of coffee from a double the extraction time is a lot less, which means that the water is in contact with the coffee for a lot less time, which to me suggests less caffeine extraction Certainly, the flavour profile of both pours is completely different, with the single extraction espresso exhibiting grater depth, complexity, and a more rounded mouth-feel, with, dare I say it, increased 'fleshiness' on the mid palate (depending upon the beans that you are using) Whereas the 'double ristretto' type extraction from the double basket produces a sweeter and some would say 'creamier' extraction, with 'bright' acidity and less bitterness I could be wrong here, but if that's the case I'd like to see the science to back up an alternative version of these events! Cheers, Pat

blanyon

Here is an abstract of an article published in Queensland, it just muddies the water more I know but I was suprised at the variation of caffeine content in espresso. Haven't been able to find one that tests the same beans with different extraction times etc. Would love to see the paper if it exists. An examination of consumer exposure to caffeine from retail coffee outlets Abstract Objective To analyse the distribution of caffeine doses obtainable from espresso coffee sold by a sample of commercial coffee vendors located on the Gold Coast, Qld, Australia. Design A cross section of

askthecoffeeguy

i've read this work - my understanding is that a cross sample of coffee blends were sampled, some which no doubt had a percentage of robusta content, which would dramatically effect the end result it didn't read like a very thorough study to me - IMHO many regular coffee drinkers would be able to tell you the difference between caffeine content for different blends, based upon their individual experience of those blends its also worth de-constructing some of the commercial blends to see what they actually put in them Segafredo for instance has I understand a significant Robusta content cheers, pat

cra

I'm a newbie, but here's my two cents: The study was thorough in that it examined what was stated in the objective. It tested how much caffiene was present in a shot of espresso from different sources. The fact that a particular cafe or shop used a blend of coffee (robusta or not) is irrelevant; the study simply undertook a comparison of what ever coffee was served. It would be interesting to examine a regular drinker's perception of caffiene content as you suggested Pat. Though I doubt they could reliably identify a difference in caffiene content <=40mg. Cheers

askthecoffeeguy

That's true but I bet those in the industry could probably say with a fair degree of certainty whether a coffee carries Robusta beans or not Also, it would be interesting to do a comparison test at the source - i.e. where the coffee is served. Take a sample espresso and measure caffeine content b/c I'm certain that it would vary greatly from one barista to another p

cra

Agree with you on that one

Henry

Fascinating stuff guys. So can I take it from your responses that one should use the single pour spout when making individual coffees. I have the sunbeam 6910 which I love. It came with the dual spout fitted so I have left it at that as I hear changing spouts can be very tricky. But from what you guys are saying I would get a better coffee experience with the single spout? Given most of my coffee making is just for me would you recommend I change to the single? Thanks Henry.

[deleted]

At my old work, we started to pull a double ristretto instead of a single espresso for every drink we made. I was always a bit worried about that ('weak' orders would just get a very short double riz, standard coffees had a double riz). Henry, the consensus was that a standard fw/cap/etc made with a double riz tasted better, but that was with our particular blend (which is quite smooth and mellow, even by Australian standards). There'd be quite a few places who would do their strongs with a double ristretto, I imagine. For the record, our strongs were double espressos, which I guess is the most common method of making strongs in Sydney, anyway. I do have to say though, with us, there was an extra charge of $0.50 to let the shot run for an extra several seconds 🙂 I have the habit now of making all coffees on a double riz base.

Henry

Interesting Billy, my understanding of a ristretto is that it's a 20ml shot, ie a normal shot minus the crema? So your strong flat whites for example was a 60ml shot whilst your standards were 40ml? Now that's what I call getting technical, how did you get it down to this degree of accuracy? Programmed machine?

[deleted]

hey Henry, on the contrary; a ristretto, if prepared correctly, should be almost completely crema - that's the golden creamy stuff, to be clear. the exact measurement of a riz is up for debate, like the exact volume of an espresso, the optimal time, etc - anything in coffee is up for debate. I think 15-20mL is generally what you'd get if you asked a standard, half-decent barista to pull you a ristretto. all our shots were manual. We used 3-group ECM Venezianos at all our locations, and the onus was upon whoever was making the coffee to prepare it to the standard generally agreed upon by everyone. i suppose if we were to average all the volumes of our strongs and standards, we'd get measurements close to 60-65/35-40. there were too many factors involved in espresso for us to be programming anything. Henry, I think you would get a nicer-tasting coffee from a double ristretto pulled through your double-spout, but that's just me and the way I've been trained most recently. There will be countless arguments to support using a single shot from a single spout, using a single side of the double spout, etc... if it's tasting good to you, that's all that matters.

FreshCoffee2

Re your last paragraph I agree, it depends on the individual's requirement as to whether they want to use a double or single portion to make their single ristretto to their taste. Which means at home, rather than in a cafe except where the owners wish to build a name based upon their "signature" (ie modified from standard) style coffees.