# Rocket Giotto Evo - Flush volumes



## dougl (Jan 13, 2012)

I'm not sure what I'm doing here. Everything I read says that the rokcet has a restrictor in the thermosyphon, so doesn't need a very big cooling flush and has a long rebound time. What does that mean in practice? The pressurestat is set to 1.2 bar max and the brew pressure is about 9.5 - 10 with a blind basket.

How long do I continue to flush after the water dance stops? And then how long do I wait before pulling the shot? Please don't forget that the Rocket is supposed to behave differently to most E61 machines because of the restrictor and a larger gicleur. Some say it behaves very similarly to a Vibiemme Domobar HX...

Any advice appreciated. The reason I am asking is that I am not getting repeatable shots. The grind is the same, the tamp is the same, the puck looks the same at the end, the taste is all over the place.


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## Glenn (Jun 14, 2008)

Hi Dougl

You shouldn't need much of a flush. How long between shots and how long has the machine been on before the first one?

After the flush, lock in the portafilter and flip the lever to start the water flowing immediately.

How long are you leaving between shots when testing?

Are you steaming milk as well?


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## dougl (Jan 13, 2012)

Too many questions Glenn!

I'll try to answer. The first flush is for the first coffee. The machine has warmed up for about 40 mins, usually an hour. I remove the portafilter, grind, fill, tamp, then flush into a cup to warm it. The flush usually almost fills the cup (probably 200mls). I count for three seconds after bubbling and steam stop coming out of the grouphead. I immediately put the loaded portafilter in and pull the shot. I then steam some milk. Fifteen or twenty minutes later I flush about 60 mls. Same routine. The second shot is normally better. I just have no feel for what the temperature of the grouphead/brew is and am sorely tempted to get one of those thermometers from the US; I feel that this step should be unnecessary though!!


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## Calidore (Jan 22, 2012)

I'm having similar problems with my brand new Cellini V2 (main difference from the earlier versions is that it has an insulated boiler, which could make a difference to recovery times, but I'd guess it's pretty marginal). I've done some cursing, though I've only had it a couple of days and patience is all. To start off with I got shots that tasted bitter/overhot, sometimes to the edge of unpleasantness. This is partly because my previous machine was a Silvia, where the chief problem was keeping it up to temperature. With the Rocket (I guess other HXs too) I'm finding the problem is the reverse. I think my machine when set at 1.2 bar needs a longer cooling flush than most articles I've read would suggest (and I'm going by taste rather than any clear understanding of what's going on inside it). So I've had good results with cooling flush before the first shot of up to 30 seconds. I then pull the shot straight away. I also think that the waiting for the 'water dance' to stop can be a bit misleading. If you look from the side or above, then the water stops looking like it's dancing quite quickly. But if you look up from underneath there are still bubbles on the shower screen for quite a while afterwards, and the water is clearly very close to boiling point even when the main part of the dance is over. I've found that flushing until I get a completely clear flow of water, no bubbles at all, then about 5 seconds more, gets things about where I want them. I'm still tinkering and learning; but what I've been trying to do is to get it to pour the coldest shot I can and then work up from there. I think that's probably the best way to hit the sweet spot. Not quite there yet, though. All part of the fun.

Would be interested to hear how you're getting on.


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## frankil (Jan 20, 2012)

Hi guys, good to know that you are experiencing the same difficulties









I also find that second shot is much better - it looks like after the first one Giotto gets into its proper temperature.

I wanted to eliminate this (as much as I can) so I have ordered EricS adapter recently and now I can not wait for it to arrive so I can play with it









I knew that owning HX will require more patience (and learning) to get consistent results but it is fun and the results are worth it!


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## big dan (Apr 11, 2012)

Old thread i know but just for reference my Giotto has a flush volume of 250ml and my boiler pressure gauge tops out at around 1.2 bar.


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## 7493 (May 29, 2014)

There is another thread about this issue but just for completeness:

My Giotto Evo 2 is set to cut in at 0.9 bar and cut out at 1.1 bar. I do not get any spitting or steam but I was getting sour shots after doing a cooling flush. Spoke to Claudette at BB and she suggested NOT doing a cooling flush at all. Tried this and sour shots cured. If they hadn't been, I would have increased the pressure to raise the temperature a bit. As it is, I have less faff, so I'm quite happy. Steaming with the standard two hole tip is fine! Nice dry steam and not too fast, which suits me.


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## Prusev71 (Mar 19, 2015)

Rob666 said:


> There is another thread about this issue but just for completeness:
> 
> My Giotto Evo 2 is set to cut in at 0.9 bar and cut out at 1.1 bar. I do not get any spitting or steam but I was getting sour shots after doing a cooling flush. Spoke to Claudette at BB and she suggested NOT doing a cooling flush at all. Tried this and sour shots cured. If they hadn't been, I would have increased the pressure to raise the temperature a bit. As it is, I have less faff, so I'm quite happy. Steaming with the standard two hole tip is fine! Nice dry steam and not too fast, which suits me.


Hi Rob666, When you had taken your buying decision, had you considered the option to buy buy the Rocket PID model (in case that you would work with the water tank) in order to make easier adjustments of the boiler temperature? Please, share your knowledge if Cellini (Giotto) PID version requires less cooling flushes - in term of length and frequency? Thank you!


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## 7493 (May 29, 2014)

Hi Prusev, I did consider the Rocket PID however, I really wanted a rotary pump. To be honest, I cannot see that having a PID instead of a (very good) pressurestat would make much if any difference to the need to flush or the flush times on an HX machine. They are both doing the same thing, i.e. controlling boiler temperature by switching the resistance on and off. This temperature / pressure setting will affect flush times though. With either type of control, the boiler temperature is going to be above boiling point and you are relying on the passage of water on the brew path through the boiler and head to achieve the desired brew temp. If the machine is left on for a long time then despite the size of the gicleur and the restrictor in the thermosiphon the brew water coming through initially will be too hot, hence the need for a cooling flush.


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## Prusev71 (Mar 19, 2015)

Rob666 said:


> Hi Prusev, I did consider the Rocket PID however, I really wanted a rotary pump. To be honest, I cannot see that having a PID instead of a (very good) pressurestat would make much if any difference to the need to flush or the flush times on an HX machine. They are both doing the same thing, i.e. controlling boiler temperature by switching the resistance on and off. This temperature / pressure setting will affect flush times though. With either type of control, the boiler temperature is going to be above boiling point and you are relying on the passage of water on the brew path through the boiler and head to achieve the desired brew temp. If the machine is left on for a long time then despite the size of the gicleur and the restrictor in the thermosiphon the brew water coming through initially will be too hot, hence the need for a cooling flush.


Thank you Rob! I asked Rocket guys and they replied that the inbound group head restrict or has 3 mm diameter. Compared with other HX machines which has no such restrictor, this machine is the best one. I discussed with Claudette the matter and she advised me never to use a group head thermometer, because it is no sense. It shows a temperatures with a huge delay and what is really matters is the cup result. She also advise to avoid cooling flushes at all, until the result in the cup requires it.







) What is your current flush routine? And if now you are plumbed in have you found a difference in the cup with the period when you had used the water tank before plumbing in?


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## 7493 (May 29, 2014)

Hi Prusev, still using the tank with Tesco's Ashbeck. I also spoke to Claudette some time ago and received much the same advice. My machine was fine with no flush at all until I de-scaled it and tried increasing the pressure a bit. Even though I've restored it to the original pressure, 0.9 bar on 1.1 bar off, it now needs a flush of maybe 250ml for the first shot if it's been on for much more than 20 minutes. Second and subsequent shots do not need a flush.

Rocket advice now is not to de-scale but to use water which will not scale up the machine. I only descaled mine because I bought it at six months old and didn't know what water it had been running with.

So, just to be clear, if my machine has been on for more than 20 minutes I flush into the cup I'm going to use until the 'water dance' stops. I.e. superheated water and steam emerging from the brew head. If it has only been on for 20 minutes it doesn't need a flush but I run a little bit to make sure. Subsequent consecutive shots I don't flush at all.


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## Prusev71 (Mar 19, 2015)

Thank you Rob,! I am happy to read that everything with your Rocket is OK. In my opinion, there is no other espresso machine vendor design to beat it! Rocket exterior is the BEST ONE! Your pattern routine means that interior of the machine also is like working horse! So, your experience shows that descaling the machine significantly changes the its behavior.

And nevertheless that you had increased the boiler pressure with Sirrai ( how much you had tried - 1.2, 1.3 bar) at the end you had decided to bring back to 1.1 bar.

Using water which does not scale up the machine is something relative, I think. Because, sooner or later, the descaling will be mandatory at certain point of time ...

Do you obtain a sweet spot in your shots with Evo v2 and how often you have had it? I think that this the most important goal. So, if the price for obtaining this result is 250 ml flush I would pay it with joy and happiness.







)

P.S. I know that Tesco is a big retailer, but what does it mean "Ashbek"?


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## 7493 (May 29, 2014)

Hi Prusev, I'm very happy with my Rocket! I tried 1.2 bar + with the Sirai and could not see any advantage so went back to 1.1 bar. We almost always drink cappuccino and hit the sweet spot most of the time. (Depending on the beans of course!) One of the advantages of the Rocket is that it is easy to achieve good and consistent results. The flush is a small price to pay.

Ashbeck is simply a Tesco 'own brand' water. It's cheap and has low calcium therefore doesn't scale


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## Prusev71 (Mar 19, 2015)

Rob666 said:


> Hi Prusev, I'm very happy with my Rocket! I tried 1.2 bar + with the Sirai and could not see any advantage so went back to 1.1 bar. We almost always drink cappuccino and hit the sweet spot most of the time. (Depending on the beans of course!) One of the advantages of the Rocket is that it is easy to achieve good and consistent results. The flush is a small price to pay.
> 
> Ashbeck is simply a Tesco 'own brand' water. It's cheap and has low calcium therefore doesn't scale


Thank you, Rob! Your routine help me a lot toward rotary pump plus water tank combination in the context of the espresso shot quality. BTW, except milk based drink, is it easy for you to make sweet spot espresso shots consistently with Rocket?


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## Thecatlinux (Mar 10, 2014)

Prusev71 said:


> is it easy for you to make sweet spot espresso shots consistently with Rocket?


just to butt in , yes consistently good shots are easily achievable . The first thing I noticed about the rocket was how consistent and repeatable the shots were , once you've found your sweet spot the rocket will knock out the same over and over and all day long .


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