# Underextracted coffee, thin crema (Silvia/Mythos)



## caffeinedealer (Aug 19, 2018)

Hi everyone,

Long time listener, first time caller. I would need your help with the issue of struggling to get a decent crema on my espresso and it tastes under-extracted with different coffees of different roasting dates (fresh or 4 weeks). The technical details:

*Rancilio Silvia V3 (2009)*

Pressure at 10 bar, measured on group head

Water temp 95-99 degrees measured on group immediately after heating element switches off (no PID, as the values show)

IMS shower screen, old bulky screw

VST 18g ridgeless basket

IMS 12-18g ridge basket

*NS Mythos Plus* (older model with the red mains switch)

Brand new Eureka steel burrs (old burrs were a mismatched pair of badly worn TiN)

Cleaned up, replaced stripped screws, installed new generation de-clumper (V-shape teeth)

Seems to be grinding in good quality, no clumps

*Brewing details:* depending on coffee profile 16/18g dose, 38/42g yield. Tried grind settings to achieve 20-35 second extractions, the result was the same regardless.

*Human factors:* 5 years in specialty coffee shops as a barista, level tamping, no problems with channeling and extracting correctly. Tried distributing in different ways and I'm using Pergtamp (the Pullman one).

Trying to figure out what could be wrong with the whole thing. Did anyone have similar issues, or could someone think of anything that might be off? Any help appreciated. I'm hoping it's something trivial, preferably human error from my side, because I would stop spending on spare parts for the moment purely based on the fact that I don't see the reward yet


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## DavecUK (Aug 6, 2013)

Assuming you know what you are doing with regard coffee freshness, grind and tamp....sounds like you do. The pressure is OK and you say the temperature is OK...then there can be no explanation. I would have said perhaps the temperature is low, but you say that was checked?

Do you have a Video of a shot?


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## caffeinedealer (Aug 19, 2018)

Temperature was indeed checked with a probe and it looks okay. The only detail I forgot to add that I had a Mahlkoenig K30 with me for a few days, and it did a good job, I've changed the burrs in the Mythos after that, but I didn't see that much of a change. I'll try to make a video later onwards.


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## El carajillo (Mar 16, 2013)

Although you have checked the pressure static with a blind basket, does the pump deliver sufficient flow when brewing ? possibly tired pump ?

What temperature is the coffee in the cup ? Try timing the volume / mass of water freely discharged by the pump against pump flow tables .

Try thermometer in styrofoam cup to check water temperature discharge ?

Have you removed the screen and cleaned behind / back-flushed ? Have you been using dark roast / oily beans ?


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## Mrboots2u (May 10, 2013)

What does it taste off, under extracted tells me nothing ....

What are the notes, provided by the roaster.

Where are you storing the coffee.

What is the coffee ? Origin etc Not all origins and or roasts are crema monsters.


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## MildredM (Feb 13, 2017)

We definitely need to know what beans you're using.


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## caffeinedealer (Aug 19, 2018)

El carajillo said:


> Although you have checked the pressure static with a blind basket, does the pump deliver sufficient flow when brewing ? possibly tired pump ?
> 
> What temperature is the coffee in the cup ? Try timing the volume / mass of water freely discharged by the pump against pump flow tables .
> 
> ...


Thanks for the ideas, didn't think of the pump delivery. Measured 515 ml/min versus the 300 cc/min I found for the Ulka EX5.

Coffee temperature was 72 degrees in the cup. Water temp as stated above varies between 95-99 degrees from the heat element switching off.

No dark/oily coffee been used, running with medium roast. Backflushed after every shot, Cafiza treatment every Saturday with the shower screen/plate off.


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## caffeinedealer (Aug 19, 2018)

Mrboots2u said:


> What does it taste off, under extracted tells me nothing ....
> 
> What are the notes, provided by the roaster.
> 
> ...


Acidic, no body, light brown crema without any dark spots or "tiger stripes", etc. I'm fully aware that Arabica has less. Coffees tried were local roasters and commercial brands as well, cross referenced with a commercial machine and range of Mazzer grinders. I'm storing the coffee in an airtight container, and it was exactly the same freshly opened.


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## Mrboots2u (May 10, 2013)

caffeinedealer said:


> Acidic, no body, light brown crema without any dark spots or "tiger stripes", etc. I'm fully aware that Arabica has less. Coffees tried were local roasters and commercial brands as well, cross referenced with a commercial machine and range of Mazzer grinders. I'm storing the coffee in an airtight container, and it was exactly the same freshly opened.


What is the origin ? Does your roaster provude you with a roast date?

What do you mean crossed referenced?


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## lake_m (Feb 4, 2017)

What is your water like? I.e. pH and hardness. Are you using a filter or bottled?


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## L&R (Mar 8, 2018)

Probably a detail but my best results with Silvia specifically are connected with lower pressure than stock 10-11bar.

9bar static works best for me.


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## Mrboots2u (May 10, 2013)

How long has the machine been on?

If you are interested enough in coffer to invest in a Mythos then you need to pod the silva or change machine. The silva is a pig to get a take temp on.


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## DavecUK (Aug 6, 2013)

Bootie you lost me there, do you mean mod the Sylvia and stable temp?


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## Mrboots2u (May 10, 2013)

DavecUK said:


> Bootie you lost me there, do you mean mod the Sylvia and stable temp?


Yeah sorry, pro grinder and machine with a 10 degree temp swing are not a great combo. So pid the silva or think about a change of machine.


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## caffeinedealer (Aug 19, 2018)

Thanks everyone for the ideas, in the end it was the pump acting up after 9 years of service. Replaced with a new one with Aerotec's guide, good as new. And quieter!

On the topic of pairing a Mythos with the Silvia: of course I have a HX machine on the christmas list, but Santa needs to save up first. I replaced a Sage Smart Grinder Pro with the Mythos Plus (old, ugly, loud, not the Climapro we're talking about), a colleague of mine was selling it for £300 so it seemed like a no brainer. Needed some work, but it was a step forward. I won't PID the Silvia for 3-4 months, but I wanted to drink as good coffee as possible. We'll need a bigger kitchen though due to the 3kg hopper.

So again, thanks for the help folks, appreciate it!


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## johnealey (May 19, 2014)

You can cut the hopper down or even do away with (stick the hopper down and put something like a tube with weight in the opening to the throat)

Or you could make yourself cry and buy a short hopper for a third (ish) of what you paid for the grinder from Bella Barista (adding in the clump crusher as well, best approx £10 you will spend on a mythos)

As to the silvia PID will help but if you saving for another machine may just need to master temp surfing









All the above can be found by searching the forum

John


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## buderim (Feb 7, 2019)

I think I may have the same problem , I have a Sunbeam EM7000 and a Breville smart grinder . I have recently been using a Quality Espresso Q10 which was a great improvement over the smart grinder I had planned on keeping the Q10 but I got offered a price that I couldnt refuse so I ended up selling it.

Last week I came across a NS Mythos plus at a very good price from a cafe that had closed down it was supposed to have had a service and new burrs a few months ago.

But I am having problems pulling a decent shot , I was thinking the burrs where never changed and are worn out , but maybe it is a problem with the Coffee machine . But as the Q10 made great shots and the Mythos doesn't so I am a bit confused..


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## Mrboots2u (May 10, 2013)

buderim said:


> I think I may have the same problem , I have a Sunbeam EM7000 and a Breville smart grinder . I have recently been using a Quality Espresso Q10 which was a great improvement over the smart grinder I had planned on keeping the Q10 but I got offered a price that I couldnt refuse so I ended up selling it.
> 
> Last week I came across a NS Mythos plus at a very good price from a cafe that had closed down it was supposed to have had a service and new burrs a few months ago.
> 
> But I am having problems pulling a decent shot , I was thinking the burrs where never changed and are worn out , but maybe it is a problem with the Coffee machine . But as the Q10 made great shots and the Mythos doesn't so I am a bit confused..


What do the burrs look like, feel like, whats the shot count on the grinder.

Whats the problem with the shot? Bitter? Acidic?


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## buderim (Feb 7, 2019)

Mrboots2u said:


> What do the burrs look like, feel like, whats the shot count on the grinder.
> 
> Whats the problem with the shot? Bitter? Acidic?


I didnt taste the shots , it looked like as if I had used stale pre-ground supermarket coffee just a watery mess . The burrs felt quite sharp they are the steel ones and have Eureka stamped on the side . The coffee was flying everywhere rather than in the portafilter .

I have been reading another thread and I am thinking there may have been a blockage which was stopping the coffee exiting the burrs properly , I have ordered a clump buster and I will give the grinding chamber a good clean and try again , I also have a 2nd Em7000 so I will try using that as well .


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## buderim (Feb 7, 2019)

I thought I would update my progress . I bought the plastic clump crusher and cleaned the burrs and the grinding chamber and the shots are now how they should be . So I think there may have been a clog in the grinding chamber that was stopping the coffee exiting and it was getting ground to finely .


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