blog from the ceo & superbarista of phoenix coffee, home of the best baristas in cleveland, ohio

Monday, November 05, 2007

Dosing Debate, Public Forum

Just picture scorecards speckled with espresso drips and how you would feel after test sipping 20 shots of espresso. And we decided to swallow, not spit. So yeah, the buzz was intense. Especially at 8:30 at night...

Last week we conducted a carefully controlled espresso dosing experiment at the Phoenix Roastery. We investigated which dosing method (dosing refers to the way the barista fills the portafilter basket) gives the best results. We are in the process of switching to all La San Marco two group machines at our stores, and the new portafilters have differently shaped baskets from our previous machines, which is how this question arose in the first place.

The "new" dosing method proposed by Dennis Skitzki, our espresso wizard, is that we fill the dosing chamber with ground espresso and adjust the dosing mechanism in each grinder to dispense precisely 8.5 grams of coffee per segment of the dosing star. The dosing star is the star-shaped divider inside the dosing chamber that parses measured amounts of coffee down the hole (from where it falls into the waiting portafilter) as it rotates with each pull of the dosing lever on the side of the grinder.

The status quo dosing method (previously espoused by the same espresso wizard) is to overfill the portafilter basket and level the basket off using a finger or the lid of the dosing chamber, much as one would measure flour in a bakery. The portafilter is essentially being used as the measuring cup.

Potential problems with the latter method are consistency of leveling and how many times the barista drags the coffee partially across the portafilter before leveling completely. Not to mention that with the La San Marco machines, this method results in more coffee in the basket, which is not necessarily a problem, but it will result in a slightly different grind size.

At our investigation last week, first we had different baristas dose ten shots worth of espresso and we weighed the dosed amounts on a gram scale. This is a very simple exercise, but very interesting. The two most consistent dosing methods were me (SWJ) using the dosing star technique, (.18 standard deviation) followed by Kim, the manager at the Superior Cafe, using the level dose method and the lid of the dosing chamber to level with (.25 standard deviation).

The second round of the investigation consisted of barista Stephen Shaum pulling 20 shots, randomly alternating between dosing methods, and therefore grind size and coffee amounts, and having a panel of judges rate each shot. Ten of the shots were prepared using the level dose method, and the other ten were prepared using the dosing star method. The judges couldn't tell which dosing method was used for which shot, so it was a blind taste test from that point of view. Flavor wise, the level dose shots got an average score of 7.183 with a standard deviation of 1.1 and the dosing star shots got an average score of 7.003 with a standard deviation of .88.

We didn't feel that the difference in the flavor ratings were statistically significant. But we did observe that since we threw out any shot that was not in the 20-30 second range, it was considerably more difficult to produce an acceptable shot on the level-dose machine. Also, there was about a pound of wasted coffee around that machine by the end of the night, versus about a quarter pound of wasted coffee around the grinder that dispensed coffee using its dosing star.

Overall, I would say at this point that I am sold on the dosing star method, due to less coffee waste and comparable taste and comparable consistency results.

But Wiggles (barista at the Coventry store) still says that the dosing star has no soul. That method gives the barista less control over the pulling of the shot. Which is why this issue has become so hotly contested! Isn't soul the most important thing in a shot of espresso anyway? I still think that's why espresso is amazing; it gives you a flavor window into the barista's soul instantaneously. If they're on their game, the espresso is good, the soul is good, life is good. If they're off their game, their spirit is crushed, well, the espresso is also.


Anonymous Anonymous said...

Hi, I am learning how to become a great barista for a cafe I work in can you maybe give me some advice and maybe some pointers on how to do it really good?

My email is


11:07 AM, November 08, 2007  
Anonymous scott said...

i believe i agree with wiggles.
that is only because at one early point in my barista career i had to use a super automatic, which at the same time made me lethargic and hungry in terms of being a barista.
therefore, now, i try to distance myself from that sort of automated espresso (and in that the 'destruction' of the art of espresso). i know perhaps this is a minute battle in the war, and from a business owner's mindframe: less waste = money going further = more money = better business, but surely the power of the art has as much a place as the power of the dollar.

best wishes, and thanks for an awesome and though-provoking blog.

10:07 PM, November 13, 2007  
Anonymous scdummy said...

My "la san marco espresso grinder" continues to drop grinded coffee after each pull. Any thoughts?

4:33 PM, January 13, 2008  
Blogger Sarah Wilson-Jones said...

I can't picture how that would happen, sorry. Maybe take your dosing star apart (difficult) and reassemble. Make sure you have a back up grinder available for use so if you can't get it back together easily, you can call for help. You'll learn a lot in the process, though.

5:30 AM, January 20, 2008  
Blogger Jason Haeger said...

This is the first time I've seen this article, and I have to say.. it left me in shock most of the time.

"Dosing star method".. so, you're pre-grinding coffee? Not good. Not good at all. If you can't detect a difference between pre-ground and fresh-ground espresso, it's probably time to find a different roaster to supply your shop.

Espresso is constantly variable. With the manual dosing method, the barista who is in-touch with their particular coffee and environment should be able to make on-the-fly adjustments from shot to shot to keep a consistently high level of quality.

If you are just dosing exactly the same amount, and you're keeping pre-ground coffee in your doser, you've just removed a huge axiom of control from the individual who could benefit the coffee most at this link of the proverbial chain.

Nope.. I don't like it. I've seen the "star dosing method" before. and I showed that same person the manual method. They were surprised at the crema. Surprised! Maybe I'm reading this wrong, but despite the increased waste, I think it's better to toss out more coffee and keep a higher quality product on the menu rather than cheap-skate the coffee waste and end up with an "OK" product.

Pinching pennies is not the recipe for success.

3:32 PM, January 22, 2009  
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