Hi Ryan,

Nate paints an accurate and very helpful picture. His explanation of what the thermometer measures pump-off vs pump-on is especially helpful to understanding the process for someone who's already as sophisticated as you. Just to close the conceptual circle:

Understand that when you flush an HX you're temping the water in the HX AND the group. They are separate entities.

The group will help modulate brew water temp which might be a few degrees too hot or too cold as it comes out of the HX. This is partly a matter of relative thermal efficiencies, and partly because the thermosiphon action of a well tuned (with a gicleur) E-61 controls the change of group temp during idle. However, it ain't perfect. Nearly all E-61 HXs fall on the Mixer continuum, and not in the Agnostic range.

Flush go and wait, and flush and go not only show different readings of an EricS thermometer at the right (dialed-in) temp, they have different intra-shot temp dynamics which some people -- me among them -- believe makes a difference in the cup. One technique is not inherently better than the other. The choice is a matter of taste, and I suggest experimenting extensively with both.

Rich

To me the first video looked ok, the only thing missing of course was coffee in the portafilter. Without the coffee in the portafilter is the equivalent to continuing the flush, hence the temperature was going down. The coffee in the portafilter helps retain the the water from flowing freely thus the temperature does not go down as rapidly.

contraflow88 wrote:To me the first video looked ok, the only thing missing of course was coffee in the portafilter. Without the coffee in the portafilter is the equivalent to continuing the flush, hence the temperature was going down. The coffee in the portafilter helps retain the the water from flowing freely thus the temperature does not go down as rapidly.

Thanks, yeah I realized this after my first post. Cue, egg on my face. Duh, I wasn't thinking at all! Of course there would be much less water flowing when extracting. So when I first made the videos, I wasn't accounting for the rapid flow rate of water without coffee in the portafilter. Now that I have been paying attention to thermometer readings with coffee in the basket, I can see that the temp is not dropping so rapidly.

boar_d_laze wrote:Hi Ryan,

Understand that when you flush an HX you're temping the water in the HX AND the group. They are separate entities.

The group will help modulate brew water temp which might be a few degrees too hot or too cold as it comes out of the HX. This is partly a matter of relative thermal efficiencies, and partly because the thermosiphon action of a well tuned (with a gicleur) E-61 controls the change of group temp during idle. However, it ain't perfect. Nearly all E-61 HXs fall on the Mixer continuum, and not in the Agnostic range.

Flush go and wait, and flush and go not only show different readings of an EricS thermometer at the right (dialed-in) temp, they have different intra-shot temp dynamics which some people -- me among them -- believe makes a difference in the cup. One technique is not inherently better than the other. The choice is a matter of taste, and I suggest experimenting extensively with both.

Rich

Thanks again Rich. I experimented a little more last night and I'm starting to feel more comfortable. Haven't had as much time as I'd like to learn the ropes just yet. But I did some more flush n' go extractions and I hit pretty stable extraction temps in the high 190s and low 200s, according to Erics thermometer.

What I've found out so far:

1) After a long warm up (46 to 60 min) or a long idle, the group needs at least a 15 to 20 second flush to get a flush n' go extraction temp in the high 190s low 200s.

2) With 2 minutes of recovery after this initial shot, a short flush of a few seconds results in a pull around 200.

Anyway, I will keep practicing. Still need to get more precise with flush time, recovery times etc.

How quickly should a machine like this be able to pull a successive shot? What is the usual recovery time?

canuckcoffeeguy wrote:How quickly should a machine like this be able to pull a successive shot? What is the usual recovery time?

I have no experience with that machine, and the speed will depend on the thermosyphon restrictor (if any), the boiler pressure, and other factors. But just so you have a rough idea, it may be in the ballpark of 3 minutes per shot.

My ECM Giotto has a 3mm restrictor (I think),** and boiler at ~1.0 bar. if I'm pulling shots as fast as possible I end up waiting on the machine - I have some time to grind and fuss with distributing and tamping. When going at max speed I'll do a little cleaning flush after removing the PF, and after that flush it's reverse thermosyponing below 196F. By the time I finish grinding and dosing it's on its way back up and when it passes 197 or so I start the next shot. The group thermometer will be indicating 202F or 203F during the pull (and I'm pretty sure the temp at the coffee bed is 2 or 3F below that.*) On my machine with this technique I can finish each shot in slightly less than 3 minutes after finishing the preceding one. (In the real world I never do - milk drinks, serving, chatting, being disorganized takes a toll.)

Eric once posted a trial (with scace graphs) on an Anita that ran about 3 minutes between each shot, and with no flushing: Erics e61 adapter, how to pull consecutive shots?


*I used to get confused and worry that I was pulling guest's coffees way too hot. Eventually got it in my head that I should see higher temps during the pull when I do these flush-n-wait series of shots than what I typically see in my morning flush-n-go.

** Eric corrected me below about that. Probably there is no restrictor in my older model Giotto. But somehow it does have a slow rebound when doing multiple shots.

After a long warm up (46 to 60 min) or a long idle, the group needs at least a 15 to 20 second flush . . .

Then you can always reduce your boiler pressure from a max of "X" bar to "X-0.1" bar. For example, if your maximum boiler pressure is, say, 1.10 bar now, reduce it to 1.00 bar max.

Flush-n-go means exactly that . . . you should have the basket and/or portafilter with basket fully ready to be inserted into the group.

Every single morning, I flush Anita down to 185 ish and start to prep the basket. I pull the shot when the group gets to around 196-197 which is a couple of minutes away.

Set your camera on a tripod and flush your fully warmed up machine to 185 with/without the PF in place. This should be about a 3 minute video. Compare your results to that in the instructions.

For Pat - It would be unusual for your ECM Giotto to have the 3.0 mm restrictor. This was instituted by Rocket (on Rocket machines) based on tests conducted on ECM machines in Australia (take that with a tiny grain of salt).

erics wrote: For Pat - It would be unusual for your ECM Giotto to have the 3.0 mm restrictor. This was instituted by Rocket (on Rocket machines) based on tests conducted on ECM machines in Australia (take that with a tiny grain of salt).

Thanks for that info Eric. I've never disconnected the fitting and checked - was just basing that on what i'd read about Rockets and assumed my ECM was no different. I'm not the original owner, so one may have been added - one of these days I'll look. It does take a long time when I try the flush-n-wait approach.

erics wrote:Then you can always reduce your boiler pressure from a max of "X" bar to "X-0.1" bar. For example, if your maximum boiler pressure is, say, 1.10 bar now, reduce it to 1.00 bar max.

Flush-n-go means exactly that . . . you should have the basket and/or portafilter with basket fully ready to be inserted into the group.

Every single morning, I flush Anita down to 185 ish and start to prep the basket. I pull the shot when the group gets to around 196-197 which is a couple of minutes away.

Set your camera on a tripod and flush your fully warmed up machine to 185 with/without the PF in place. This should be about a 3 minute video. Compare your results to that in the instructions.

Thanks Eric. I'm going to make a video of this test as soon as I can. I likely won't be able to do it until tomorrow or Saturday. Just to confirm I'm flushing from a full 60 minute warm-up, until the thermometer reading goes down to 185. Then I stop flushing immediately. However, this 185 reading shows the temp of the water passing by the thermometer. So once I stop flushing, will the group still show 185, or will it be another temp?

In related news, I'm feeling more comfortable with temp management, after the 5 or 6 shots I pulled last night. I tried the flush n' go initially from an hour warm-up, then followed with additional shots at various set intervals, with varying flush lengths. I guess these follow-up shots are considered flush n' wait extractions.

I still have a long way to go to master the flushing and recover of my particular machine. But I was definitely in the right ball park. Below are my results. Originally hand scribbled so I'm hoping they're accurate.

Oh, and I've included a pic of the first soy latte I've ever attempted. While not pretty, it tasted good. And I managed to make decent microfoam, considering the Magica steams like a beast.

My initial shot:
-60 minute warm up
-group idle temp = 203.5F
-20 second flush: temp rises and then drops to 203.5F...stop flushing
-pull 18g double = pretty stable temp of 196F

Subsequent shot (2 minutes later)
-Group idle temp = 196F (if actual temp at puck is 3 degrees higher, then the real temp is 199, right?)
-5 second flush: temp 195
-pull 18g double = temp reading of 206 (if the actual puck temp is 3 degrees lower, then the real temp is 203, right?)

Subsequent shot(3 minutes later
-group idle = 193F
-flush to 205
-pull 18g double: shot temp starts at 203 and eventually drops to 201

Subsequent shot(5 minutes later)
-group ideal = 196.2F
-15 second flush = 205
-pull 18g double: pretty stable temp of 197

Subsequent shot (2 minutes later)
-group idle = 194F
-5 second flush = ???(forgot to write this down)
-pull 18g double: temp of 206-207 during extraction

Subsequent shot(5 minutes later)
-group idle = 195F
-10 second flush = 208
-pull 18g double: 200 then down to 197 at end of extraction

Subsequent shot(5 minutes later)
-group idle = 193F
-7 second flush = 208
-pull 18g double: 204 to 206 during extraction

I'll post the 185 flush video once I get a chance to do it.
Thanks again everyone for your help and patience!

On my Bezzera Magica, I've used Eric's group adapter with K thermocouple and other two TCs on the thermosyphon pipes, for quite a while, and I have hundreds of session recordings depicting briliant shots or disastrous ones; one session means 4-6 doubles in the morning, sometimes 2 in the afternoon;
maybe you can use one of these session recording to see the particularities of Magica thermal behaviour, which is mainly of a mixer type, with higer enough thermal memory and long recoveries;
and this, due to its design including something of a flow restrictor (4 mm inner diam tube, not a disk) in the TSyph upper pipe at its HX end:


as we know, the group is quite stabile thermally and in Magica case, it takes an excessive long cooling flush - about 30s - to bring the water through the termocouple, to 84C (184F); then another excessive long interval of 4:25 to reach into the group, that 90.2C (194.5F) for starting a shot - with about 4C higher, to 94C (201.5F) during extraction; it could be ok for a single shot session, but when I start, my family - 3-4 people - are ready to complain about any delay

anyway, at least my usual routine is worth being mentioned, as it is derived from observations on sessions datalogs;
here it is a session profile:

(a larger image)
boiling temp at my place is 98.1C (208.5F);
pstat max: 1.2 bar;
autofill probes: 2 mm visible outside (hence, on the lower position);

as general habits, I work on a flush-and-wait at the begining of the session, and seldom, after long pauses, using any cooling flush at all;
also, the shot initiation is on the descending part of the group temp profile, or mostly, after the temp in group reaches a certain plateau, before starting to raise again; however these moments are better controled by watching the temperatures on the (higher) termosiphon pipes;

temp of the first shot:
after 60 min from power on, with 1.2 bar max pstat, the E61 temperature is about 96.5C-97C (cca. 205-206F) and the cooling flush (18 - 21sec) will bring the group temp down at 95-93C (203-200C), depending of the 'flush to' temperature;
usually, the grup temp (E61 thermocouple) is 1-2C higher than the "flush to" temp, immediately after stopping the flush; then, the group temp is decreasing (almost linearly) to 90-90.5C (194-195F) after 150s up to 180s from the end of flush, a right moment for starting the 1-st shot;
also, in this interval, there will be a thermosyphon inverse flow, then the normal flow will be resumed (at cca. 80 secs after end of flush) and the temperatures in the 2 pipes will increase toward a stabile status, considered (by me:) when the upper pipe has over 108C (226F), after that 150-180s interval, and the 1-st shot could be initiated;

temp of the next consecutive shots:
with a normal 1-st shot, the machine enters a rather stabile pattern for the next (4-6) consecutive shots:
no cooling flush between shots, just very short cleaning flushes (1-3s) immediately (well, 10-15s) after each end of shot;
start of next shot is best timed by the thermosyphon entering a stabile status with a slower increase in temperatures; that is, after the temp in the upper pipe is over 107-108C;
but there is a way this moment is reflected in the evolution of group temperature: when this temperature ceases to decrease, entering a flat zone, somewhere between 88-90C (around 192F), for 30-40sec, then starts to increase slowly; it's the beginig (first 10s) of this stabile temperature plateau of the group, when I start the shot;
all these coresponds to a 100-120 secs interval between shots;
with the above described timing respected, the extraction temp for a shot depends mainly of the pstat setting, hence the boiler temp;
usually, with max. pstat at 1.2 bar, I get a good dialed-up shot at 93,5C, with 0.0 - 0.3C variation after the initial HX hump (first 10s approx.);

I have no SCACE device and I understand how limited method is the styrofoam cup, so I do not care much about the temp diff between Erics's adapter point of measure (as I call group temp - main reference for me) and the surface of the puck; this themp diff is far from being constant, sometimes, while brewing, the temp in the group is higher than above the puck etc.
what counts obviously, is the cup result, confronted with all available data recorded and seen (botomless PF);

all the above, are descriptions of the temp profiles in the included charts;
as a more practical approach:
1. full idle - that is for me, temperatures of around 97C (206F) in the group, 99C (210F) on lower TS pipe and 113C (235F) on the upper TS pipe;
2. initial flush 4-5 sec after flashboil for a total of 19-20s, that is to a group temp (Eric's adapter) closer to target extraction temp;
3. up to 3 min pause - preparing first shot;
4. monitor the extraction water temp in group, during 1-st shot, but also the bottomless PF (!);
5. short cleaning flush after the shot;
6. pause 100-120s between shots, to prepare next shot;
7. initiate next shot, then back to 4;

when I make a longer pause:
- if it's around 3 min, just initiate next shot as usual; a 0.5C warmer shot, up to 95C is OK;
- if it's 3 to 7 min, a cooling flush of around 6 sec is necessary, but not going (flush-and-go) immediately after with the shot, only after a 40-50 sec recovery;
- at 10 min pause and after, it's towards a 'full idle', but I keep the flush only for the flashboil duration (cca. 8-10s); obviously, the group temperature has significance, as after 10 min pause, the group temp is about 92C (198F), hence much lower than at full idle;

a few words about 1-st shot (when it is the only shot) as alternatives to the above description:
I get a goot extraction temp control in grup, by initiating the 1-st shot when, after the initial flush, the temp rise in group reaches approx. 1.8C under the target temp, say at 91.7C (197F), with an extraction temp of 93.4C (200F);
usually it happens at 2 min after the flush stop (then the group temp starts to rise rather steep - in less than a min being above 108C):

also, I've got a good 1-st shot, initiating it even sooner, at cca. 80s after end of flush, while thermosyphon is still inversed; in this case, the temp of the group is almost the temp of the extraction:

(a larger image)
But, it worth mentioning that during espresso sessions, I am working in my pace, seldom watching the laptop screen, as the records are used by me for a later analysis;

radudanutco wrote:...maybe you can use one of these session recording to see the particularities of Magica thermal behaviour, which is mainly of a mixer type, with higer enough thermal memory and long recoveries;

Thanks radudanutco! Wow, you've done some extensive testing of the Magica. I can't say I understand everything you've put in your detailed post. But I'm working on deciphering all that information.

I'm the only coffee drinker in my house; so most of the time, I will only make one drink per session. Would you say that a flush n' go routine would work best in this case? In other words, 60 minute warm-up. My group idles at around 204F (1.1 boiler setting). Flush to around 203F. Then immediately pull the shot.

What do you think?

I'll have more time this weekend to make videos and test my machine. I'm going to do a video of flushing to 185F and then see how my Magica rebounds. I'm sure I'll have some more questions for you very soon. Thanks again!

canuckcoffeeguy wrote:...60 minute warm-up. My group idles at around 204F (1.1 boiler setting). Flush to around 203F. Then immediately pull the shot.
What do you think?...

I didn't state it clearly in my previous post, but I was not able to get a honorable extraction with flush-and-go...so I am now considering Magica with its longer recoveries, best suited for flush-and-wait;

your 60 min idle, with group at 204F and flush to 203F are fine for me; then:
- the best HX profile seems to be if you allow for a 3 min interval after end of first flush, then initiate 1-st (and only) shot; you should watch the temp while extracting, it could be 201-202F;
- an alternative would be to initiate earlier, after 2 min, if the group temp is around 197F; the extraction profile is good enough, with slighty lower plateau temperature, cca. 200F;
- also I started first shot even earlier, at about 85 sec after end of flush; the group temp is higher than in the above alternatives, at 198-199F, with extraction at cca. 199F;

a shot initated even earlier, towards flush-and-go, has kind of an bad temp profile, as the group is colder and the water is coming colder from HX for about 20-30 sec after end of flush;
I've tried flush-and-go after a long pause between shots, when it could be acceptable (sorry, temperatures in my charts are Celsius):

however, I get better profiles by alowing for 30-40s pause after an intermediate cooling flush, as I've told in my previous post;

well, the machine is so tolerant you can have a shot almost anywhere into the timeline of a session, i.e., with a short flush, just for exiting flashboil; once I did forget to do the initial flush after a 70 min idle; I realized it hearing the flashboil while extracting first shot... so first shot was at 209F, second at 205F and the rest were quite good, at around 201F;