Replies to This Discussion

Permalink Reply by Shadow on December 22, 2009 at 9:07am

Depends.... on the bean used for each, the extraction rate for both, etc. Based on what I've read an "average" 8 oz. cup of drip has 80-100 mg. of caffeine. A 2 oz. double shot can have as much as 80 mg . or so. So ounce for ounce the spro definitely trumps it. Most of our customers think they are going to get wired by a simple double shot in their drink.... but I hate to tell them that's usually not the case. Most think "espresso" is like liquid meth. They think because it is so concentrated and has such a pungent taste it must be killer strength..... the name conjures up a magical status somehow.... Later!

• ▶ Reply

Permalink Reply by Jared Rutledge on December 22, 2009 at 9:15am

espresso has more caffeine than drip, it's just that espresso is never served in drip like quantities. so if we say that roughly, 8 oz. of drip coffee has the same caffeine as a 2 oz. double espresso (80mg), we've clarified the issue. i just tell people a shot is equal to four ounces of drip coffee and they're usually satisfied with that.

now if you served 8 oz. of espresso, that's another matter entirely.

• ▶ Reply

Permalink Reply by Brady on December 22, 2009 at 10:48am

The answer is "it depends". Coffee is complicated, you know...

(BTW, The rest of this post are to the best of my knowledge, and I welcome any (well-documented) corrections to errors in this information.)

Ounce for ounce, espresso will usually contain more caffeine than drip, simply due to concentration. However, as Shadow has pointed out, it depends on the process.

Generally, caffeine content in the drink varies depending on two factors: how much was in the roasted bean and how much was extracted into the finished beverage. Caffeine extracts later in the process than other compounds. SO if you are getting a good extraction and pull it ristretto you'll have less caffeine in the finished beverage than if you pulled a normale. A lungo shot has still more caffeine.

I'm sure that grind and temperature affect caffeine extraction as well, since these influence the extraction of other compounds from the bean, though I'm not sure to what extent. I suspect that a hotter extraction will draw more out, as will a finer grind.

The same applies to drip, by the way. Process variations influence caffeine content in the cup. An under-extracted batch should contain less caffeine than an over-extracted batch of equal concentration.

What does this mean? As I understand it, if you pull a nice SO double ristretto shot and use it to make an americano that is roughly equal in strength to a well-made cup of drip from the same bean and roast, the americano will have less caffeine in it than the drip.

To avoid bruising your ego, you could always say "well it depends". As a matter of fact, I'm finding that this is usually the right answer for any coffee question :).

Hope this helps. Looking for helpful external references as we speak.

• ▶ Reply

Permalink Reply by Mike M on December 23, 2009 at 3:34am

Brady mentioned the two factors being the caffeine content of the bean and the extraction method, but which one carries more weight? Would a robusta espresso shot have more caffeine than an arabica blend drip coffee? Just curious.

• ▶ Reply

Permalink Reply by Brady on December 23, 2009 at 5:59am

Mike Morand said:

Brady mentioned the two factors being the caffeine content of the bean and the extraction method, but which one carries more weight? Would a robusta espresso shot have more caffeine than an arabica blend drip coffee? Just curious.

It depends :)

• ▶ Reply

Permalink Reply by Valentin David on December 23, 2009 at 6:50am

Wikipedia cites Mayoclinic.com, so obviously should not contradict it. If you find a contradiction you should tell it on the discussion page of the Wikipedia's entry. But for what I have read, it is not the case.

Testing level of caffeine in coffee is expensive. It involves very precise optical machines and computers. Of course there is the D+Caf test strip. But since I never saw any scientific paper about how it works... and if it does work, I guess this is just a scam (they actually get very strange results which would confirm it is just a scam). Moreover they talked a lot about it on TV... it is a bad sign.

There are a lot of factors that will change the concentration of caffeine. Basically everything will have an effect. But the question is what has more effect? The answer is very expensive to know. And as long as we do not have cheap way to test for caffeine concentration, we will probably not know very well.

There is more caffeine per volume in espresso but less per serving. This is a fact. But further than this, you should accept not knowing what thing during extraction could change the concentration of caffeine.

• ▶ Reply

Permalink Reply by illudereludere on December 24, 2009 at 2:58am

Valentin David said:

But further than this, you should accept not knowing what thing during extraction could change the concentration of caffeine.

No, I don't want to accept this. I don't mean to sound pissy but I am a little insulted. Then again, how were you to know? I have extracted caffeine from a sample of everything and indeed it is a taxing task as mentioned in previous responses. So! In light of this, please do delve (if you know) what thing it is during extraction that could change the concentration of caffeine.

• ▶ Reply

Permalink Reply by illudereludere on December 24, 2009 at 3:04am

Brady said:

Hope this helps. Looking for helpful external references as we speak.

LOL it does. Thanks.

• ▶ Reply

Permalink Reply by Brady on December 24, 2009 at 5:04am

OK, here's a couple of things I've found over on coffeed:

http://www.coffeed.com/viewtopic.php?f=21&t=1496&hilit=caff...
http://www.coffeed.com/viewtopic.php?f=21&t=1624&hilit=caff...

Though these discussion deals more with the effects of different roast levels than barista-controlled factors, they are still good discussions.

An interesting question. I'll be looking for more on this in the future, but not this week. illudereludere, I'd suggest you do some digging on Coffeed and Coffee Geek, get a copy of Illy and read it, and dig around elsewhere if you'd like more info on the subject. After this, you might try asking Alistair to post the question on Coffeed... however you should really do as much of your own research as you can on the subject first. Stay away from the more general sources or medical sites... stick to coffee-oriented sites with good documentation.

Now, it may well be that the impacts of different factors is not well known. I know many of us have just accepted that there will be variation and moved on. Coffee is a natural product, caffeine is a naturally-occurring substance that will vary due to factors beyond our control. Having a ballpark number to toss out if a customer asks is all many of us need. The bottom line is, if a customer is concerned about caffeine, they ought to drink decaf.

That said, if you'd like to perform some testing to nail down the correlations between different process variables and final caffeine content, please feel free.

• ▶ Reply

▶ Reply to Discussion