Hi,

I need some help! I got a Izzo Vivi PID HX-machine, but since its a hx i didn't really know the flush-time before I measured it yesterday.

My question is, based on the following diagram, what is the best time (from time = 0s) to stop flushing, and start brewing the espresso?

Tnx!


Simple explanation for the three curves:

Red = The machine has been inactive for < 30 min, PID temperature in the boiler is 124[c].

Brown = The machine has been inactive for > 10 min, PID temperature in the boiler is 124[c].

Blue = The machine has been inactive for > 10 min, PID temperature in the boiler is 126[c].



**All temperatures has been measured from the outgoing water at the brew-head when flushing, with the single portafilter loaded, but without the basket in the portafilter.


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Your're going to need to explain the source of those temperatures. I'm hoping they are not the PID readout.

That's a good point!

I just added a simple explanation.

Tnx!

Here's a picture of the machine also. (I think it goes under a different name some places)

I do believe your best bet would be to consult some of the articles in the "Resources Section" of this site.

/resources.html

Your particular machine is NOT sold over here but from what little I know of the machine, it does run hot. Warming up the machine for ABOUT an hour with the portafilter in place will give you a good starting point. Adjusting the PID temperature to the lowest level that will also provide adequate steaming will assist in reducing the amount of water flushed through the group.

Probable, but i'm not sure what temperature to aim for.

Is it a goal, when considering temperature stability, to flush as little as possible?

-Just curious, why do you sign "Skål"? And are you referring to a toast?

I run a PID HX e61. The boiler idles about 0.65bar / set point is 233°F.
Using Eric's adapter, the group idles about 200°F

My routine :
Machine on 1hr+
Sink first shot
On shots 2+, flush 5 seconds on old puck
Load PF
Flush to ~206°F on Eric's adapter, maybe 3 or 4 seconds
Pull. Shot temp is 200°F

Adjust individual brew temp up or down by longer or shorter flushes.
Adjust global idle temp via PID

sversimo wrote:Probable, but i'm not sure what temperature to aim for.

If you haven't done so already, read How How I Stopped Worrying and Learned to Love HXs. To your question:

sversimo wrote:Is it a goal, when considering temperature stability, to flush as little as possible?

It depends on the espresso machine. Some designs depend on the flush to stabilize the group; I elaborated on this point in this post:

HB wrote:Having written a number of reviews, I've come to recognize differing degrees of how heat exchanger-centric a particular espresso machine is. My shorthand for these distinctions are:

• Dragon - key characteristics are lots of flash boiling, fast recovery, nearly zero thermal memory, and slowly rising brew temperature profile. Simply stated, after the cooling flush, the heat exchanger output is the brew temperature. Examples include the Elektra Semiautomatica, Gaggia Achille, and the Olympia Maximatic.
• Mixer - key characteristics are modest flush, medium to slow recovery, considerable thermal memory, and initial rising then falling brew profile. Unlike the Dragon, the Mixer's brew temperature isn't determined solely by the output of the heat exchanger. Other factors, such as cool water mixing via an heat exchanger injector, backflow from a thermosyphon, and the attenuating effect of a heavy grouphead temper the final brew temperature. Examples include HX E61 espresso machines like the Vibiemme Domobar Super and Quickmill Vetrano.
• Agnostic - key characteristics are small, fixed volume flush or none at all, and long thermal memory. Careful tuning of a Mixer with tweaks in the design can produce an espresso machine that is heat exchanger in name only. Examples include the Cimbali Junior and Nuova Simonelli Aurelia.

As the last entry suggests, these categories are not immutable. With minor modifications or boiler pressure adjustments coupled with barista techniques, an espresso machine that naturally fits in one category can morph into one of the other categories (e.g, Ian's HX Heaven or 1½ Boiler).

The practical benefit of recognizing the characteristics of heat exchangers is the time saved learning the correct brew temperature management scheme (**). For example, I recognized the Maximatic as a Dragon by flushing the group until the water stopped flash boiling, waiting a minute or so, then repeating; it was fully recovered. The Elektra Semiautomatica is also a Dragon with a slightly heavier grouphead, but they share the same flush-n-go technique for targeting the brew temperature.

As suggested in the above post, the look and sound of the flush offer important clues on when to stop the flush. If you post a video of the Izzo's flush with decent sound quality, I'll offer my opinion on when a good stopping point would be.

Hi Everyone,

I'd just like to take a moment and say that I'm quite excited to be a new member at Home-Barista and can't wait to delve into the forums and add to all the wonderful information that has allowed me to hone my espresso techniques in my kitchen, even with my entry level equipment.

As this is my first post I was delighted to stumble across someone with the same questions as I do so perhaps we can tackle them together. I have also recently come into possession of an Izzo Vivi (upgrade from Hamilton Beach/Baratza Maestro) so I am new to the world of HX machines. As these machines aren't too common in North America there isn't the greatest wealth of knowledge from fellow Izzo users, but it is nice to hear those who have them are very happy. Although my last 8 days with the vivi have been filled with ups and downs, I am off to a good start! My version is the MK1, and not the PID'd MKII but the machines are very similar with you take a look at the "guts". I would like however to take the next step with this machine and narrow down the variations in my cooling flush technique. to go along with what Dan had said about posting a video, I was able to shoot one with my iphone and I believe the audio should work well enough to hear the changes in the sound. hopefully you can provide some advice on when to stop the flush as well as some recovery time suggestions.

Virtual_Xi wrote:...hopefully you can provide some advice on when to stop the flush as well as some recovery time suggestions.

The boiling flash ended around the 27 second mark. I don't know this particular model, but assuming it behaves like most E61 HX espresso machines, a flush-n-go would be 4-6 seconds past flash boil plus 10 second rebound.

I have done some measurements of the flushtemp and with:

- 124 degC boiler temp, ~1.4bar
- Idle time of 30 min



Time [seconds] Temperature [Celsius]
-2 76,2
-1 76,2
0 76,2
1 85,0
2 98,0
3 99,4
4 99,5
5 99,8
6 99,9
7 100,0
8 100,0
9 100,0
10 100,0
11 100,1
12 100,0
13 100,1
14 100,1
15 100,0
16 100,0
17 100,1
18 100,0
19 100,0
20 100,0
21 100,0
22 100,0
23 100,0
24 99,9
25 99,9
26 99,9
27 99,9
28 99,8
29 99,8
30 99,8
31 99,7
32 99,6
33 99,4
34 99,1
35 98,7
36 98,4
37 98,3
38 97,9
39 97,8
40 97,5
41 97,1
42 96,9
43 96,4
44 96,2
45 95,5
46 95,3
47 95,1 The machine needs 47sec to achieve 95.1 degC. [Flush temperature without a portafilter loaded]
48 94,7
49 94,5
50 94,2
51 93,5
52 93,5
53 93,1
54 92,3
55 91,9
56 92,2
57 91,9
58 91,6
59 91,1
60 90,5
61 90,2
62 89,7