I've been posting over on cg about a non-sputtering e61 I have and somone suggested I try a post here. I just received an ECM Giotto and seem to be getting only to about 190 - 195' brew temps. I've seen the cool down flush on Chris' coffee site, but I don't get that sputtering when cooling the head. When I pour water from the hot water spout through my tc'd pf, it reads 212, so I think it's reading true. I've increased the pstat & deadband to a range of 1.35 - 1.5. Without the pf in place though, I still don't get a sputtering head and wondered if that's normal or not.

Thanks,
Geoff

Geoff,

Welcome to HB. The Sputtering occurs only after the machine has been idle for a little while. The Brew Temperature reading depends on how you measure it. So:

1) Wait for the machine to be idle for 20 minutes, and flush. To accentuate sputtering, leave the Giotto Single Spout PF in the Group as you do your flush. Make sure you DO NOT have the basket in. You should see clear sputtering.

2) How exactly do you measure brew temperature? Do you have Coffee in the P/F when you run the shot, or a sponge, or is it empty? What thermometer do you use, and where do you place the T/C?

As Abe explains this is normal. You can use the presence of sputtering to gauge how long your machine has been idle and how long of a flush is required. The sputtering is more than anything a reflection of the current brew temperature.

wookie wrote:As Abe explains this is normal.

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crudo20 wrote:When I pour water from the hot water spout through my tc'd pf, it reads 212, so I think it's reading true. I've increased the pstat & deadband to a range of 1.35 - 1.5.

Um, maybe I have misinterpreted, but it appears like you're saying that the boiler pressure is running as high as 1.5 but your water spigot exit temp is only 212. On the Giotto this shouldn't be physically possible.

The first thing to do is confirm your thermometer in boiling water to see if it reads 212. Then check a steam table to discover that the boiler temp should be MUCH higher than 212 at 1 bar.

Jim Shulman provided this information at CoffeeGeek before:

Boiler Pressure----Boiler Temp--------HX & Espresso Temp
0.84 bar----------117.5C = 244F------88C-90C = 190F-194F
1.00 bar----------120.0C = 248F------90C-92C = 194F-198F
1.17 bar----------122.5C = 253F------92C-94C = 198F-201F
1.33 bar----------125.0C = 257F------94C-96C = 201F-205F

NOTE: I believe the "HX Temp" refers to steady pour temp after the HX is cleared of any water that had set idle in there for any time...

Unless I'm terribly misinformed (which is always possible ) the Giotto hot water spigot is plumbed direct from the boiler so water should exit at boiler temperature.

If you're machine has been idle more than 2 minutes and your boiler pressure reads over 1.3 bars you should definitely see and hear sputtering w/steam if you draw water with no portafilter in place.

JonR10 wrote:Um, maybe I have misinterpreted, but it appears like you're saying that the boiler pressure is running as high as 1.5 but your water spigot exit temp is only 212. On the Giotto this shouldn't be physically possible.

Remember the water exiting the spigot is no longer under 1.5 bar pressure; the boiling point is thus determined by the local atmospheric pressure. The sputtering is the water flash boiling and that's what the thermometer is measuring - boiling water (the steam is too fleeting and surrounded by boiling water to push the temperature over 212F).

I agree that 1.5 bar is very high for a Giotto. The Giotto Premium I tested was regulated to ~1.1 bar and it had a long flush (about eight ounces, IIRC). Not as vigorous as some machines and not as dramatic as the video I made. The machine was intentionally left idle for over an hour and I used a single pour spout to exaggerate the sputtering.

HB wrote:Remember the water exiting the spigot is no longer under 1.5 bar pressure; the boiling point is thus determined by the local atmospheric pressure.

While this is a good point, remember that Geoff (OP) is above sea level.

HB wrote:The sputtering is the water flash boiling and that's what the thermometer is measuring - boiling water (the steam is too fleeting and surrounded by boiling water to push the temperature over 212F).

Another excellent point, and I should have considered that.

But let's also remember that Geoff is saying that his pressure gauge is reading over 1.3 bar and he sees NO sputtering at all when he goes to run a flush. He has also indicated that he measures 190F - 195F brewing temperature. If the boiler is running at over 1.3 bar then the brewing temperature should be quite a bit higher, and certainly over 200F.

I would suggest that something is amiss....

Jon, I agree that there's an inconsistency to the story and my suspicion is some misinterpretation or mismeasurement. The Giotto running at 1.5 bar would rightly be described as "blazing hot" and the flush to brew temperature would be huge. Of the machines I've tested, the Giotto Premium is second only to the Expobar Lever in required flush amounts.

Thanks for all the replies. I calibrated boiling point on my rig - and it reads 209-210' and our elevation is ~1,400 ft, so it should be right. Pouring hot water from the machine's hot water tap reads around the 210 to 213 range, IIRC. I thought this would rule out error with the probe placement etc, but I do doubt my thermometer skills (long story - think grilled chicken and dry as a bone, dried out brisket, etc etc.. . I've adjusted the pstat and deadband for a boiler range of 1.35 - 1.5 min/max and checked temps after idling for hours.

If it should sputter through the single spout, shouldn't it sputter like crazy without any PF in at all? I thought it should, spraying boiling hot water all over the kitchen, but it just smoothly showers out of the grouphead, no hissing / sputtering at all. The only thing that sputters and steams like an angry dragon is the hot water spout. The machine had recent service (descale, pstat, softener) - but it's not possible to mix up the lines going from the head to the hot water spout, is it?

Abe - I haven't put the TC in the head w/ coffee - but I did try packing it with sponges or foil and with and without the basket. I think I had the highest readings when it was packed with foil and no basket (per one of Jim S' postings on CG). This is with the TC on my Tenma DMM.

Dan - I'm suspicious of most things I do also.

Thanks,
Geoff

crudo20 wrote:...it's not possible to mix up the lines going from the head to the hot water spout, is it?

No. This diagram from How I Stopped Worrying and Learned to Love HXs gives the general layout:



Questions about sputtering aside for a moment, how's the espresso taste?

crudo20 wrote:If it should sputter through the single spout, shouldn't it sputter like crazy without any PF in at all? I thought it should, spraying boiling hot water all over the kitchen, but it just smoothly showers out of the group head, no hissing / sputtering at all.

1) You need to reduce your pressure to 1.1 bars. That is, when it falls under 1.1 bars the heat element kicks in. You are way too hot on the Giotto.

2) With the noise of the pump in the background, it is hard to hear the hissing on the Giotto. "Sputtering" without the P/F translates to bubbles, like boiling water bubbles showering out of the P/F. Those bubbles induce the water dance. In other words, the stream of water is not flat and straight, and you will notice some steam which indicates the water is too hot. After about 5 oz it settles down.

Abe - I haven't put the TC in the head w/ coffee - but I did try packing it with sponges or foil and with and without the basket. I think I had the highest readings when it was packed with foil and no basket (per one of Jim S' postings on CG). This is with the TC on my Tenma DMM.

I don't know enough about your thermometer or T/C. You need a very accurate one and a 36 gage type T or K T/C. With the basket in the P/F, snake the T/C over the basket rim and have it touch the basket bottom around the center. Lock the P/F in (the T/C is between the P/F rim and the grouphead, but don't worry, it won't break if it is 36 gage. Alternatively, you can take the basket out and just snake it in from the bottom of the P/F through the single spout and let it rest at the P/F bottom.)

After 40 minutes idle time, run a flush with your T/C in the P/F to measure flush temperature. It should read as follows:

~210-211 f for 4 oz, and then gradually go down to 201f around 8 oz.
Again, your pressure stat should be @ 1.1 bars.

Now if you want to test Brew temperature, it must be done during a real shot, that is with coffee in the P/F. use the "Snake the T/C over the P/F rim" method I described above.

I generally prefer using a flush chart on the Giotto, and not follow the water dance. I published mine on C/G awhile back here.