Hi guys,

I just upgraded from a used Nuova Simonelli Oscar (with OPV and restrictors) to a used (<1 y.o.) Rocket Giotto Evo v2, and I'm having trouble. Can you help?
In line with DaveUK's advice, I adjusted the Sirai to just over 1.2 bar peak, other than that no changes. I use the reservoir.

On the Oscar I was able to flush a bit (lots of steam, etc), and go. On the Giotto, whatever flush routine I try, I get awful results.
When I flush the Giotto, it hisses for a while (let's say 133-150ml/4.5-5oz (seems like more water than the Oscar)), then stops. I figured I could just lock the portafilter at this point and go - is that correct?
I also tried flushing until mid-hiss and flushing until well after the hiss then waiting ~20s with no real change in taste between the three.

My process: Grinding with Mazzer Major - 17g in, 34-40ml out in 25-30s (counting from the moment I lift the lever). I'm using beans from Square Mile (Guji Mormora), roasted on the 10th.

It's super frustrating having upgraded and getting worse coffee

I suggest getting an Eric's Thermometer to give you a better idea of your brew temperature. Without it you're really just estimating and it will be difficult to establish a routine that will consistently give you the results you want.

Reduce your maximum boiler pressure to 1.00 bar. This will reduce the flushing requirements.

As Eric S. wrote, lower to 1.0. You can play with 0.8 up to 1.0 to see how things go. I've found 0.8 to not deliver hot enough coffee, but others all recommend the 0.8 to 1.0 range. Let us know how it turns out.

I've had a Rocket Evo v1 for 6 years and am getting consistent results. I have a Sirai pressurestat and it goes between 1.1 and 1.3 bar. So, that's an average of 1.2 bar. I get plenty of steam from that setting and get consistent results pulling shots. I do have Eric's thermostat installed, which is a great help in understanding what the machine is doing. I believe you can get one from Chris Coffee.

I let the machine warm up for an hour to reach full temperature. I typically flush to the point where the flashing stops, which is 5-6 ounces. I then wait about 10 seconds and pull my shot. If your shots are bitter, then flush longer. If your shots are sour, then reduce flushing. Or, adjust the wait times accordingly.

This is pretty much exactly what I was going to post.

On my Cellini, I flush about 6 ounces. I tried my pressurestat down at 1.0 but moved it back up so I could pull more than 2 shots without the temp getting too low. Follow the above advice and you should be set. EricS's thermometer would help a ton as well.

Thanks for all the advice guys!

dsblv wrote:I've had a Rocket Evo v1 for 6 years and am getting consistent results. I have a Sirai pressurestat and it goes between 1.1 and 1.3 bar. So, that's an average of 1.2 bar. I get plenty of steam from that setting and get consistent results pulling shots. I do have Eric's thermostat installed, which is a great help in understanding what the machine is doing. I believe you can get one from Chris Coffee.

I let the machine warm up for an hour to reach full temperature. I typically flush to the point where the flashing stops, which is 5-6 ounces. I then wait about 10 seconds and pull my shot. If your shots are bitter, then flush longer. If your shots are sour, then reduce flushing. Or, adjust the wait times accordingly.

I will try this out!
I often pull a second shot. How much do you tend to flush for this one (assuming the prep takes a couple of minutes)?

Thanks!

The second shot can be tricky. If it's been a few minutes since the first shot, I do a very short flush (an ounce or less) and pull the shot.

Hey there, Rocket Evo V1 here.

As others said, get Eric's thermometer. It's cheap, super easy to install and will take out all guess work. Mine's been going strong for several years now.

Anyway, i've got my pressure stat cycling around 1.1 bar, temps is running around 209 F in my particular situation. From a standing idle, I will flush around 5-6 oz (one competition style cappuccino cup) to get to a brew temp of 199-200 F. Works for the coffees i'm using on a regular basis.

Second shot usually follows around 3-4 minutes later (yes i'm slow in the morning and I always hand deliver my wife's cup to her!). I'll then need to flush maybe 3-4 oz to get same results.