Quite sour almost undrinkable espresso

Need help with equipment usage or want to share your latest discovery?

#1: Post by dramaticDelta »

machine: rancilio silvia
grinder: rancilio rocky
scale: Brewista Intelligent scale II
bean: Guatemala los volcanos (self roast)

I have had my rancilio silvia for about 6 years, when it was new I was making great coffee on it but over time it's gotten a more and more sour taste.

I recently had it in the "shop" (a local espresso shop called kaffemekka) where they changed the pump on my request and cleaned the kettle and checked through it.
They measured the thermal relays to be in order and working well.
It has very little chalk buildup as I backflush it every week and once in a while (every 4-5 months'ish) treat it with some dechalking remedies. I also only use filtered water and I have an "oscar" in the water tank (recent addition): https://idrinkcoffee.com/products/bilt- ... r-softener

I have tried dosing in many different ways and roasting both light and dark but the coffee always comes out very sour, too sour to drink. If I have a very over extracted cup it's simultaneously sour and bitter. for my aerospress I much prefer a very light roast.

Right now for my morning coffee and my wife's cappuccino i grind 17.1 grams of coffee at finest or second finest setting on the rocky, it pours out over 30 seconds to 50 grams of liquid +-5 grams, there's very little crema. my spent puck comes out firm, but not dry, it holds together as I dump it.

here ares some pictures, keep in mind that the weighs are a bit off as the pictures are taken while experimenting with different doses, baskets and grinds, but the result is more or less the same unpleasant sour coffee with little to no crema https://imgur.com/a/NQuCn3L

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#2: Post by happycat »

dramaticDelta wrote: I have had my rancilio silvia for about 6 years, when it was new I was making great coffee on it but over time it's gotten a more and more sour taste.


I also only use filtered water and I have an "oscar" in the water tank (recent addition): https://idrinkcoffee.com/products/bilt- ... r-softener
Sour can be cold water, but it can also be water with no minerals in it to properly brew the coffee chemically.

Check water temperature. You might also run the steam a but before brewing a shot.

Try using some tap water or bottled water that is not demineralized. I suggest you ask for help in the water forum here on HB.

Link to info on water issues:

https://alt.coffee.narkive.com/jICoVZzO ... sour-shots
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#3: Post by Randy G. »

If you can, go back to the shop, explain the problem, and ask them (while you are there) to make some coffee. Let us know if it tastes better. I have some suspicions, but do not want you to spend money of have perceived prejudice about the cause until you can do that test.
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dramaticDelta (original poster)

#4: Post by dramaticDelta (original poster) »

Yeah I was actually also thinking about doing this, if nothing else to rule out that the bean is of low quality. (or a bunch of other things that can go awry when roasting) I think I'll call them tomorrow and try.

I have tried just buying their "standard" coffee "Super Crema" as they call it, with very similar results (very sour coffee).

With that in mind how does "straight" water from your machines taste like? mine taste slighty metalic but it's very plain otherwise.


#5: Post by Pressino »

If the machine itself is working properly...ie. the boiler heats the water up to good brewing temp (this could be aproblem if the boiler itself got scaled or the heating element is not working properly), then I really would suspect your grinder is not able to grind fine enough. Your Rocky's burrs may be wearing out...and in any case it is not really a great espresso grinder. You can check if this is the problem by simply grinding a dose at the finest setting. If that does not choke your machine, the grinder is at fault. The machine may also have problems, but that will be apparent when you grind finer with another grinder.


#6: Post by apease »

My situation seems similar although with a new machine, so as a newbie to the forum I hope this is the right place to post.

I'm having problems with a sour/bitter espresso with little or no crema on my new Vivaldi Mini II that I received last week. I was using a KitchenAid espresso machine for the past 3 years, but bought the Vivaldi after my second KitchenAid unit broke. I still have the matching KitchenAid ceramic burr grinder. My wife learned how to roast beans fresh a few months ago while we still had the old KitchenAid, using beans from Sweet Maria's. It made a huge difference and I was happy with the espresso I was making. It had good crema and wasn't sour or bitter. I didn't know about extraction time or weighing grind weight or output.

After I ordered the Vivaldi I watched many of James Hoffman's videos. At a 7 out of 8 setting on the grinder, using the old KitchenAid espresso maker I'd just fill up espresso shot glasses and it was working well. Now with the Vivaldi I've tried settings from 6.5-8 on the grinder, times from 20 sec to a full minute and shot ratios of 1:1.5 to 1:3, all with the same bad tasting result. I've tried our home-roasted, fairly dark beans and Clive Coffee's complimentary blond beans that came with the new machine. I wait until the unit warms up and also run a blank shot through the group head and portafilter.

Maybe my grinder doesn't have fine enough settings and the ideal grind is somehow in between the settings? Could espresso be more temperamental than I thought? I'd be grateful for any advice.

dramaticDelta (original poster)

#7: Post by dramaticDelta (original poster) »

Alright, so I found the issue and resolved it :oops:

The issue was the grinder

Resolved by disassembling the grinder and cleaning each part separately, a process made difficult by chinesium screws that are really over tightened from the factory and the fact that the grinder "cup" is what attaches the motor to the body of the grinder.

some pictures, viewer discretion advised.

Unfortunately the rocky grinder is made in a way that it will slowly build up a lot of grime over time, the "grindz" will help clean the blades but not the rest of the assembly

As mentioned, you really have to take the whole thing apart in order to properly clean the parts that get dirty, something I don't imagine a lot of people do. it would have been quite simple to make it in a way that you only unloaded stuff above the motor for cleaning but that is not how it's made.

To my dismay I also discovered that the first cup of coffee of the day will always contain day old grinds :(

funny thing is, I went to the shop to see how my coffee tasted there, we grinded it in their grinder and pulled a shot on their machine, and it was sour! then the owner started talking about how my roaster the "gene cafe" is a terrible roaster that gives inconsistent results and that's the source of my misery. then we poured a shot of their roast, and it had a bit more crema but it was also sour :lol:

the lady that had first greeted me in the shop advised me to run some grindz through the grinder which eventually lead me to my disturbing discovery.

I have pulled a few shots, they are no longer sour!!!! they actually taste significantly better than what the shots they pulled at the shop with their own roast, despite my terrible roast.

I did learn a couple of things about my roasting technique so I will use that to improve my shots even further.

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#8: Post by apease »

very intriguing! I guess I should try to disassemble and clean my KitchenAid grinder and see if that works. Or convince my wife that I should buy a better grinder :-)


#9: Post by apease »

Inspired by the grinder dissection pictures, I've also attempted to give my KitchenAid grinder a thorough cleaning, and while I was at it, calibrated it to favor fine grinds (thanks to YouTube!). There were a lot of stray grinds that I suspect were making the grinds uneven. And they didn't smell good. I guess that home roasting in the past few months produced a more oily bean and that the oils had gone off in our hot California summer. They jury is still out though on whether this was successful since the morning espressos I made today were better, but certainly not up to par.


#10: Post by apease »

Many thanks for the Grindz suggestion. It seems to have helped a great deal with both taste and making the grinds more even, even after what I thought was a thorough cleaning of my grinder. It may take another day or two (at current caffeination tolerances!) to dial in my recipe after changing the calibration of my grinder but this is real progress