# Gaggia Evolution - Oily, Bitter Coffee With A Covering Of White Residue!



## EViS (Aug 25, 2010)

I have a Gaggia Evolution, which I believe is the Gaggia Baby?

*Never Descaled Before...*

In the four years that I have owned her, I have never descaled her until the other day and purchased a new outlet valve from gaggiamanualservice.com as mine was so seized up with scale the inner screw split in half whilst trying to seperate the two parts!

*Descaled With Lemon Juice...*

I descaled with lemon juice mixed with water over a couple of hours. I then flushed the machine around 10 times with clean water prior to re-inserting the new valve.

*Flow Rate...*

Water flows in a shower form and the machine outputs 125ml in 20 seconds. Is this good? Prior to this, it got so bad that it took a couple of minutes to get 125ml with a very slow drip!

*Quality Of Water & Coffee...*

Once the machine warms up for around 10 minutes, the water comes out rather murky, but clears in around 5 seconds.

When making a cup of coffee, the coffee has a milky residue around the side of the mug which clears after a couple of minutes. It also has an oily appearance on the surface and tastes somewhat bitter. see attached picture

How do I go about solving this? (I do like coffee, but somewhat inexperienced when it comes to making a professional brew)


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## Glenn (Jun 14, 2008)

My advice would be to flush lots more water though, and to use a descaler (not lemon juice) that is specifically for the Gaggia machines (eg this one

The water should come out clean in the first place.

If this is murky you may need to get the boiler flushed.

If you add cold milk to the brew in your picture, do you get lumpy white bits (where the milk has curdled)?


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## Osh (Jun 15, 2010)

If the boiler of your machine is aluminium, you should consider using descaler made from tartaric acid. This way, you can leave it for longer periods in the boiler without having to worry about corrosion.

You can buy it on ebay quite cheaply, or from home brewing shops.

When you say murky, I think you mean it is full of small bubbles which quickly dissipate. This is normal, as you can sometimes see happening from your hot water tap.

Another point to mention is, to descale properly you will need to remove the shower holding plate. See this link on how to do that. There will be a lot scale on top of that piece which greatly affects the water dispersion and flow.


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## EViS (Aug 25, 2010)

Glenn said:


> My advice would be to flush lots more water though, and to use a descaler (not lemon juice) that is specifically for the Gaggia machines (eg this one
> 
> The water should come out clean in the first place.
> 
> ...


Hi Glenn,

a) In what way is that descaler any different to say a homebase (own brand) one? (genuine question, not trying to be difficult, I have some homebase own-brand descaler in the cupboard but was weary about using it on the machine)

b) I'd need to check the milk part now that the machine has been 'cleaned', although I haven't in the past, no.


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## EViS (Aug 25, 2010)

Osh said:


> If the boiler of your machine is aluminium, you should consider using descaler made from tartaric acid. This way, you can leave it for longer periods in the boiler without having to worry about corrosion.
> 
> You can buy it on ebay quite cheaply, or from home brewing shops.
> 
> ...


Hi Osh,

3) Is the descaler that Glenn linked to one you would also recommend (i.e. from tartaric acid)?

4) Yes there are a thousands of bubbles, however not sure I've ever seen a hot-water tap emitting water like this before...?

5) I removed the shower holding plate and then the outlet valve (small spanner as opposed to allen-key) prior to descaling.


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## EViS (Aug 25, 2010)

One other question (sorry fellas!),

6) Would you recommend a backflush on this machine? If so, how do you do one? I have searched the forum and there is a lot of controversy about this procedure however nowhere can I find a guide on how to do this?


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## Glenn (Jun 14, 2008)

Your machine cannot be backflushed due to the lack of a solenoid.

What ingredients were listed in the Homebase own brand descaler?


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## EViS (Aug 25, 2010)

Is the solenoid the 3-way valve? If my Gaggia Evolution is in fact the Gaggia Baby, then I am under the impression that it does have a solenoid (3-way valve)?

The Homebase own brand descaler that I have is in fact a "Sainsbury's All Purpose Descaler" and nowhere does it have the ingredients listed...


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## Glenn (Jun 14, 2008)

Gaggia Baby machines do have solenoids

Gaggia Evolution machines do not

Your machine will be one or the other and the advice will differ depending which model you have

What is the model number shown on the mack or base of the machine?


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## Osh (Jun 15, 2010)

EViS said:


> Hi Osh,
> 
> 3) Is the descaler that Glenn linked to one you would also recommend (i.e. from tartaric acid)?
> 
> ...


3) I would recommend it, but I don't think it is tartaric acid. You can see on Happy Donkey that they say not to leave it too long in aluminium boilers. Gaggia make their own tartaric acid based descaler, as sold here. However, you can see for yourself the price. Much more economical to buy your own. Most over the shelf descalers are citric acid.

4) It depends on your hot water system at home. I have an unvented system, where this is quite common. It is gases being released from the water.

5) I am not sure what your machine needs to remove the plate, or if it indeed has a shower holding plate. I would need to see a parts diagram.

As far as I am aware, the Evolution is a different machine to the Baby.


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## EViS (Aug 25, 2010)

Glenn said:


> Gaggia Baby machines do have solenoids
> 
> Gaggia Evolution machines do not
> 
> ...


 Right, so not the same machine then. The underneath states as follows:



> Mod: Espresso Evolution
> 
> No: 010409 [...]
> 
> 05/2004


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## EViS (Aug 25, 2010)

Glenn said:


> If you add cold milk to the brew in your picture, do you get lumpy white bits (where the milk has curdled)?


Milk mixes in fine, no curdling. What would curdling mean? That there is still some descaler (lemon juice) inside the machine?


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## Glenn (Jun 14, 2008)

Correct. Curdling indicates chemicals and acids still present


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## EViS (Aug 25, 2010)

Quick update, no idea what has happened but all of a sudden the coffee no longer tastes bitter or looks oily







! However, the 'shower' is no longer working as it should which clearly indicates more scale has come through. Will need to de-scale again followed by keeping this as a routine. How often should descaling be done for a machine that is used a *handful of times per week*?


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## Osh (Jun 15, 2010)

Depends on how hard the water is in your area.

For hard water areas, I would say monthly should definitely be sufficient.


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## EViS (Aug 25, 2010)

Thanks Osh







.


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