What's the key criteria for stopping espresso extraction?

Beginner and pro baristas share tips and tricks.

#1: Post by jovial »

I'm confused as to which factor is the most important factor in stopping the espresso extraction,
or in other words which is a proper indication of perfect coffee brewing.

I've read that a good espresso extraction (for one filter cup) relates to the following properties:

1. it is an ounce of espresso (in quantity)
2. it takes 12 to 15 seconds to extract (in time)
3. and has (perferably three-colored) crema on top, that loosens in texture at the end of extraction (in quality)

I have to admit, my espresso shots don't meet _all_ the above criteria at the end....
for example, i have noticed that I can get more crema if I extract more than one ounce.

so, if i'm not getting the perfect shots yet, which one of the above factors should I prioritize and try to maintain while practicing and trying to get the other factors right?


#2: Post by Zendel »

Your extraction time should be in the neighborhood of 25-30 seconds. I think the key to stopping the extraction is the color of the flow.

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#3: Post by HB »

Jim explains this well in Working the Shot of The Home Barista's Guide to Espresso (emphasis added):
another_jim wrote:The first aspect of working the shot is to make sure the extraction is correct by ending the shot at the same color every time. The exact color depends on blend and machine, but it is always a light tan described by experienced baristas as blonde. If the stream is still well filled with crema, it is not yet blonde. If the stream entering the cup discolors the crema into a light tan color, it's gotten lighter than blonde. Typically the right point is around the time when the stream starts changing from foam to liquid.
He goes on to explain Al's Rule and the Rule of Thirds. It's a must-read guide in my opinion. Another great way to gather opinions on the "right time" is with a video, e.g., Videos of espresso extractions. I don't make all that many videos, especially since the house is rarely quiet enough for them. Below is one I made for the Buyer's Guide to the Gaggia Achille:

Also on youtube
«missing video»

Not the best shot I've ever pulled, but a good one. The transition point from foam to liquid was around the 60 second mark of the video.
Dan Kehn

jovial (original poster)

#4: Post by jovial (original poster) »

Zendel wrote:Your extraction time should be in the neighborhood of 25-30 seconds. I think the key to stopping the extraction is the color of the flow.
Zendel and HB, thank you for your replies.
I have seen many espresso extraction videos, but sadly not many with a pressurized portafilter (which is what i'm stuck with).

have a look at this video please....
«missing video»

the espresso extraction time in this video is 12 seconds from the moment that the machine is turned on to the end of extraction.....
it is in the region of 8 seconds if you start counting from the time that the espresso starts appearing.
(agreed, the guy doesn't tamp at all (which deserves a question on its own, considering his expertize), and some of that crema is fake... but look at the espresso... it looks good)
would you call this guys espresso shot under-extracted ??

I've experimented with various grinds (too fine to even get stuck in my portafilter holes) and tamping pressure (have tamped so much, was almost thinking my portafilter is bent at the bottom yesterday!)
and i've never been able to stretch the extraction time into this 25 to 30 seconds region.

it's as if my machine is just programmed to give me a fixed water flow rate.... and the more i try to lower the flow rate, the louder it gets, and the worse the espresso turns out to be.

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#5: Post by another_jim »

A pressurized portafilter removes almost all the control over extraction parameters. Tamping and grind variations alone will not help -- since most of the pressure drop is happening at the restrictor orifice. This means the fines won't migrate and a regular puck won't form. In general, these machines produce a flow color at the start of the shot that is lighter than where I end my shot on a regular machine. This doesn't necessarily mean the coffee is wimpy, it means the optics of pressurized PF flow is different from that of unpressurized PFs. My guess is that the bubbles in the flow are much larger, since restrictor crema always looks sudsy.

The trick to a good extraction is creating a good puck and maintaining it during the shot, nothing more, nothing less. Since you don't get any help from the machine, you'll need to do this for yourself before you start the shot. While I'm not at all sure how to go about doing this, I do have some suggestions on things to try, based on tall-tale like stories of Paul Bassett's prowess with these machines and the physics of percolation:

1. Overfill the basket so that the PF is hard to insert into the group -- this will keep the puck solid rather than turning it into a slurry

2. Tappity tap the heck out of the basket or PF after you've filled it with grounds, but before you tamp. The idea is that the vibration will get the fines to the bottom of the puck, where they belong -- this is usually done by the first five seconds of flow, but it probably doesn't happen in a pressurized basket.

3. Grind fine enough so the above two techniques have the machine dancing on the edge of self-destruction when pulling the shots. According to the Bassett stories, this is quite essential. In any case, the sooner this machine self-destructs, the sooner you can get a proper one.
Jim Schulman

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#6: Post by HB »

jovial wrote:...and some of that crema is fake... but look at the espresso... it looks good) would you call this guys espresso shot under-extracted ??
Jim gave you some excellent advice. To be certain we're on the same page though, that shot doesn't look the least bit appealing to me. Pale blond and uniform "crema" produced in less than 15 seconds. All the espressos I've tasted extracted at that rate were weak, low in body, and sour (or bitter/sour due to combined temperature/extraction issues).

Contrast the espresso you see in the video with this one from Illy's The Complexity of Coffee:

  • Hazelnut coloring with reddish reflections
Or this one from John Weiss' WDT:
  • Image
    Gorgeous striping and excellent coloration
Now that looks good.
Dan Kehn

jovial (original poster)

#7: Post by jovial (original poster) »

Jim, I think you're quite right.

Opinions on the subject of pressurized portafilters vary alot.

On the positive side, we have opinions like this:
"Pressurized Portafilter. This type of portafilter creates the pressure for you. That's right, it is not dependent on your tamping and grinding correctly. They have a device that will only allow the water to pass when the appropriate pressure has been developed. These systems were created to make it easier to obtain good coffee. Espresso is known for its intense flavor, but many users came to think that it was nothing but bitter. If they knew to make some simple adjustments they would have saved their palate. To bypass this experience the pressurized portafilters were developed. Some use a valve and others use a special filter basket. The result is the same for both, proper pressure development and excellent espresso." (source http://www.wholelattelove.com/articles/ ... ilters.cfm)

On the negative side, we have opinions, some as harsh as this:
"When the espresso goes through that valve, any true crema is destroyed." (source http://www.espressomacchina.ca/before/bigcaveat.html)

And, my opinion is increasingly shifting towards the negative side now.......

There's no need for self-destruction... as soon as I get another negative feedback on this pressurized portafilter business,
i'll make the following picture a true reality.


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jovial (original poster)

#8: Post by jovial (original poster) »

oh, looks like HB posted a message while I was writing mine.

Thanks HB, I think i'm gonna de-pressurize my portafilter or get my hands on an Elektra filter basket.
This pressurized portafilter business, I think is now out of question.

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#9: Post by jesawdy »

another_jim wrote:In any case, the sooner this machine self-destructs, the sooner you can get a proper one.
Ha! Funny....

But seriously, on another note, if you have that same machine you can do yourself some help by acquiring a replacement portafilter for it. You can get a non-pressurized version. If you are in the US, try Saeco USA direct (http://www.saeco-usa.com/), or calling one of their authorized repair centers or maybe even espressoparts.com. The non-pressurized version is a bit of an eyesore compared to the more attractive looking one it comes with. I have seen used ones on coffeegeek.com (and others looking for them). (A friend has gotten good service from Coffee Boss in CORNELIUS, NC Tel: 704-987-3310 for a superauto part).

A 25-30 second extraction is quite doable with the replacement portafilter. Fresh beans of course, and the grinder (always the grinder) needs to be up to the task. The one in the video CAN do it, but you'll have maybe one or two usable espresso settings, and the gods will need to be one your side. I think the basket is 52 or 53mm, so a tamper would be helpful (or something approximating one at least).

Let us know more about your setup, machine, grinder, beans, and see about acquiring a new portafilter.
Jeff Sawdy

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#10: Post by DC »

Contrast the espresso you see in the video with this one from Illy's The Complexity of Coffee:
Or this one from John Weiss' WDT:
Wow... I've never been served/been able to make espresso that has that deep a red-brown colour to the flow or with crema even close to being the colour of that one from the illy pic. Looks like hot chocolate! :(