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Dialing in a new espresso machine, a step by step guide

Postby cannonfodder on Thu Jan 11, 2007 11:14 pm

Help, I just got a new espresso machine and my shots are horrible!

If you frequent the forums, you have no doubt seen this reoccurring topic. Dialing in a new machine for an inexperienced Barista can be a bit daunting, especially if you have a new grinder to accompany that shiny new espresso machine.

Many novice users start with too high an expectation and the incorrect assumption that if I purchase a quality espresso machine and grinder I can automatically make good espresso. Just because you own an espresso machine does not mean you can make espresso.

It takes time and a lot of practice to develop the basic Barista skills of grind, dose and tamp. In practice it sounds simple, grind your beans, dose them into the portafilter, mash it flat and make your cup. Unfortunately, this is deceivingly simplistic. It is more akin to an algebraic formula, each variable being dependent on the others. By changing one variable, you change the dynamics of the entire equation.

Too often a new Barista goes about the process in an over exuberant fashion changing the grind, dose, tamp, brew pressure, boiler pressure, coffee blend etc... all at the same time. The key to make one change at a time, observe the results and make another small change based on your observation.

I am the new owner of an Elektra A3 espresso machine. So I decided to document my dialing in of the machine and grind in hopes of helping others with the same process. My kit did not include a new grinder; I am still using my La Cimbali Jr. grinder so I already know how my grinder will respond to a change.
Image

I loaded up the grinder with some two week+ old coffee; this is well beyond its prime but should still have enough serviceable life in it to get started. I set my grinder on 4.5 which I knew was too coarse. These are the frightening results.

Shot one, the grinder set at 4.5, 50 pound tamp, and 20 gram dose in the stock double basket. As you can see, 20 grams was too much, the machine was choked and the extraction barely started. The pucks surface was grinding against the shower screen due to the over dosed basket.


Shot two. I kept the grind and tamp the same and reduced the dose to 18 grams. My scale was jumping between 18 and 19 grams so this was a heavy 18 gram dose. I do have to say that having read Dan's review on the A3, I already knew it did not respond well to overdosing.

Let me also add that this dose did not make heavy contact with the shower screen but was very, very close. To check that, dose and tamp your portafilter then lock it into the group. Then remove the portafilter. If you can see even the lightest impression of a screw head or other parts of the shower screen, you are still overdosed. This dose was just touching on the outer edges of the puck.

You may want to stand back from your computer for this one. You don't want to get sprayed in the eye.


Boy, that one was nasty, but we now know what happens when we change the dose from 20, to 18+ grams. If you look closely at the photo below, you can see several pinholes in the puck, those are the sources of the channeling.
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Shot three. I kept the grind and tamp the same as shots one and two but further reduced the dose to 17 grams. The headspace was just about right on this one. The massive channeling was reduced although the shot was way too fast and I still had donut extractions. The perimeter of the basket starts first but we have a slow spot in the center of the basket.


After these three shots we have learned that the A3 does not like to be overdosed. With the given grind and tamp, the 17 gram dose provided adequate headspace and the best extraction of the three. The next step is to fine up the grind one notch in an attempt to slow the extraction. I start with a dose of 18 grams while keeping the distribution and tamp the same. Why go back to 18 grams? As I stated above, all of these variables are dependent on each other. Since we changed the grind, the dose may have been effected as well. So I am bracketing the extraction again to see what effect it has.

The grinder is now set at 4.25, the dose is 18 grams and the distribution and tamp remain the same. The extraction was better than the original 18 gram dose. The shot starts more even but still favors the front of the basket. It develops nicely but half way through the shot we see signs of channeling, then suddenly the flow runs fast and blond.


For the fifth shot I retain the 4.25 grind setting and down dose to 17 grams, once again keeping the distribution and tamp the same. This time the shot starts more abrupt and flows faster. We still have some channeling, the 18 gram dose worked best with the finer grind.


So after 5 shots what have we learned. The A3 does not like to be over dosed. The 17 and 18 gram dose worked best depending on the grind that was used. We also learned that two week old beans are not going to produce an acceptable shot. So for those of you that spend $2000 for you kit and decide to use cheap grocery store beans to dial in your machine, you are wasting your time. If two week old beans are too stale to produce a good shot, what do you think two month old beans will do. Please, do yourself a favor and invest in two pounds of good beans to learn with. We also discovered that my tamp favors the front of the basket. That has nothing to do with the machine or grinder, but a flaw in the Barista's (my) technique.

More to come.
Dave Stephens
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Postby another_jim on Thu Jan 11, 2007 11:30 pm

Nice intro to working a new machine.

BTW, you might consider sometime trying 14 grams and a grind roughly 15 degrees of a turn on the grinder collar finer; that works better for the Semi, and the group bell is the same on both machines. The donut extraction was a headache on the semi doubles too; and it gets worse the deeper the puck. If you like 18-19 gram shots, consider a triple basket; I have a friend in Evanston who uses that dose/basket on this group.
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Postby cannonfodder on Thu Jan 11, 2007 11:58 pm

Thanks for the heads up on the dose. The donut of death extractions are usually a symptom of too much coffee with too coarse a grind and too hard a tamp. I would not have guessed a 14 gram dose though. That is really cutting it down but the Elektra has a relatively thick dispersion block which reduces headspace.

Under normal conditions, I would have jumped to a finer grind and lower dose but that would defeat the purpose of the thread. Hopefully, this will help provide systematic flow process to assist the first time home user.

I had planned on adding a frothing guide but steaming on the A3 is so easy there is not much to show. Just stick the wand in the milk and flip the lever. No surfing, no standing on one foot while angling the pitcher 15 degrees while chanting 'be one with the milk'. Just stick the wand in the milk and go. Wonderfully simple and the best wet microfoam I have ever made. I really like this machine.

I also must point out that using grams for the dose can be deceiving. Some blends are denser than other so the same weight dose may have different volumes in the basket. The trick is volume not weight. This is where I like ridged baskets. That basket ridge gives me a consistent point of measurement. The tamper piston is also a good indicator. Make note of how deep in the basket your tamper sits. That will let know if you up or down dosed and help you gain dosing consistency.
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Postby another_jim on Fri Jan 12, 2007 1:04 am

cannonfodder wrote:I also must point out that using grams for the dose can be deceiving. Some blends are denser than other so the same weight dose may have different volumes in the basket. The trick is volume not weight. This is where I like ridged baskets. That basket ridge gives me a consistent point of measurement. The tamper piston is also a good indicator. Make note of how deep in the basket your tamper sits. That will let know if you up or down dosed and help you gain dosing consistency.


Hmm, I wonder. Cellulose is cellulose. If the coffee is denser the cause is that it has less vacuoles (air pockets) in its cell structure. Less airspace means a thin layer may resist the flow just as much as a thicker layer of a less dense bean. So it could be dosing by weight provides a more consistent taste and grind than dosing by volume. I'm not sure about any of this, but it's something that needs testing (unless I missed reading about it)
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Postby chelya on Fri Jan 12, 2007 1:13 am

Great videos and descriptions. It is very educational. I am looking forward to part 2.
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Postby edwa on Fri Jan 12, 2007 10:53 am

Great thread! After you finish part 2 my suggestion would be to post this in the How Tos section as a great tool for diagnosing extractions. Kind of a visual glossary.

I could use a little more explanation of the "donut" in shot 3. I have watched it over and over because it goes so fast. Any chance we could get some more detail/definition? You state that you have a slow spot in the center. That's hard for me to see (it is first thing in the morning), at what second count is it most visible?

Very thankful for all the work you obviously put into this.
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Postby cannonfodder on Fri Jan 12, 2007 2:15 pm

In the previous session I learned that an overdosed basket and old beans make for a disastrous mess. We had lots of channeling, uneven flow and donut extractions.

Allow me to clarify the 'donut' phrase. If you watch the first 4 seconds of the extractions you will notice that the outside of the basket starts flowing first. That outer edge extraction then quickly closes in radiating from the outer edge to the center. You will also notice a very small spot in the center of the basket that has no flow. If you watch the streams, you will notice them dancing around the center of the basket but do not converge into a single centered stream until several seconds after the extraction starts. Those dancing streams are caused in part by the lack of flow from the center of the basket.

Once the streams do converge the cone still sways and moves around the bottom of the basket. That movement is caused by an uneven flow of coffee. As one location starts to channel, or dry up, the cone will migrate toward the area of faster flow. Even in the absence of obvious channeling jets, we know the extraction is uneven based on the behavior of the stream and cone. Also watch for the twister effect. That is where the striping of the flow twists as it flows down the cone forming a 'tornado'.

For the next session we have gone to fresh beans. The blend is the same but the beans are three days out of the roaster. They are still a little fresh and still degassing which will cause a large cone to form due to the excess carbon dioxide being emitted from the beans. Another tell tale sign of too fresh a bean is the crema in the cup. A shot that consists of 2oz (coffee and crema) will quickly settle and go flat. Your two ounce shot quickly becomes a 1.25 ounce shot as the 'false' crema falls. Keep in mind that a shot, even from properly rested beans, will settle over time. A two ounce shot will settle down to about 1.75-1.5 ounces if left to sit for a minute.

So taking what we have learned from the first series, we move on. I have switched to a fresh roast, same blend but only three days out of the roaster (I home roast). Knowing that fresh beans take a coarser grind, I reset my grinder to 4.5 and put in my beans. Taking a lesson from the first series, I dose my basket to 18 grams and use the same distribution and tamp as the first set.

Once again let me point out that consistency is your friend. If you are new at espresso, and if you are reading this you probably are, you may want to invest $20 in a kitchen scale that does both grams and ounces. Then you can confirm your dose is consistent at the beginning of the learning process.

Listen closely and you can hear my wife playing with the dog in the background. I forgot to mute the audio.


The donut extraction is still there but what a difference fresh beans make. The flow quickly healed up and looked good until we get to the final 10 seconds. Then it goes down the tubes again. We have channeling and the dreaded dancing twister cone.

We have learned that even with fresh beans we still have extraction problems. The flow rate of the shot was close so changing our grind will not yield any better results. The next step is to modify the dose but that will have to wait for installment 3.
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Postby cannonfodder on Fri Jan 12, 2007 2:30 pm

another_jim wrote:Hmm, I wonder. Cellulose is cellulose. If the coffee is denser the cause is that it has less vacuoles (air pockets) in its cell structure. Less airspace means a thin layer may resist the flow just as much as a thicker layer of a less dense bean. So it could be dosing by weight provides a more consistent taste and grind than dosing by volume. I'm not sure about any of this, but it's something that needs testing (unless I missed reading about it)


I have had two different blends vary by a gram when comparing volumetric dosing to weight. Those heavier blends are usually a lighter roast and contain a lot of high grown hard bean like Yemen or Papua New Guinea peaberry. Testing your theory may yield some interesting results.
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Postby cafeIKE on Fri Jan 12, 2007 9:10 pm

cannonfodder wrote:My scale was jumping between 18 and 19 grams so this was a heavy 18 gram dose.

cannonfodder wrote:I have had two different blends vary by a gram when comparing volumetric dosing to weight...


Does your scale measure fractional grams?

Digital scales have an accuracy tolerance and a count error. A scale that indicates single grams probably has at best 1 gram accuracy and a 1 count error. This gives ±1g plus ±1 count for a total error range of 4 which is far too much for a ~18g total : ~20%.

If one wants to weigh espresso doses, a scale that measure tenths of grams is more appropriate. The error count is still 4, but the magnitude is reduced by 10 for a 0.4g error in ~18g : ~2%

Additionally, accuracy changes with time and temperature, so recalibrate frequently.

That being said, I never weigh doses. Coffee is organic, changing constantly. It's easier to adjust the grinder and / or up / down dose. Not as specific numerically, but just as effective in getting a good shot.

Nice write up on the start-up.
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Postby cannonfodder on Fri Jan 12, 2007 11:42 pm

The scale is a single gram so the error margin is high and not ideal for exact measurements, but for the purpose of this dialing in process, it is adequate. Regardless of whether the scale displays 17 grams but actually contains 19.5 grams of coffee, as long as it consistently reads 17 grams we are OK. The point is not to precisely measure the dose, but to provide a reference point.

Normally I take a more holistic approach with my dosing. I know when it is right because it feels right. Unfortunately, that does not provide much of a reference point for someone that is trying to dial in their first espresso machine. With time and practice, the need for a scale or even a thermometer will disappear. When starting, having a reference point to provide a repeatable variable helps with initial tuning.
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