Like others have mentioned, the PID fluctuates while the machine is idle. I can set the PID brew boiler temp at 203 degrees and it will fluctuate in between 203-207. It almost always fluctuates by a few degrees at any temperature PID setting. It rarely shows the actual temperature I have set and almost always overshoots by a few degrees while sometimes fluctuating.

Is this to compensate for the degrees lost when in route to the portafilter? So I set it to 201 in the PID settings, then it shows 203, but when you pour a shot, it will be at 201 by the time it hits the coffee? Or is it fluctuating due to instability?

In other words, I'm trying to figure out how to get the most accurate temperatures possible. I've seen all sorts of conflicting things online.

Lastly, how much do you guys flush before shots?

My procedure:

0. Warm up 45 minutes
1. Run brew head (fully) with portafilter in filling up 1.5 ounce shot glass (4-5 seconds)
2. Remove portafilter, dry, grind coffee and tamp
3. Dump shot glass and run brew head (fully) again filling up 1.5 ounce shot glass (4-5 seconds)
4. Lock portafilter, preinfuse just until beading of espresso shows on the bottom and then run brew head fully and start the shot timer

You should not pay too much attention to the PID displayed temp. If you want to brew at lets say 200*F, then set your PID to 200. The fluctuation that you see is the temp of the water inside the brew boiler near the cold water INLET into the boiler. That is why you see fluctuation. However, the mass of the brass of the grouphead is what stabilizes the temp at 200. Remember that there is an offset / difference of 19*F between the actual water temp and the PID displayed temp.

In order to achieve the correct 200*F in the above example, flush about 1.5 - 2 oz of water to heat up the head. Grind your coffee, tamp, lock in, and start you shot. The temp will be 200*F at the head (even if the display shows differently!).

You know the Duetto has an E61 head that already has a pre infusion, right? You don't really need make your own, but if you want to, that's fine too. But, you start the shot timing from the start of the pre-infusion.

Thanks for the info, thats what I figured, but I wanted to make sure. I couldn't get the consistency I am getting shot to shot if it wasn't stable. When you say the offset is 19 degrees, that is factored into the machine right? Is that offset highly accurate?

So it is best to simply flush only once in the beginning, not a second time 20-30 seconds later after grinding and tamping?

I know it has pre-infusion already - but I thought it was not bad to pre-infuse longer - it can only help right?

Why start the shot from the beginning of pre-infusion if there is no pressure on the puck? I pre-infuse for around 8 seconds, or until I see beading on the bottom of the portafilter, then I start the shot fully and the timer at the same time. If I started the timer at first pre-infusion it would be a very short shot so I would have to coarsen the grind which would then make it blonde very quickly.

Yes, the 19*F offset is already programmed into the PID from the factory. You don't need to do anything about that. In the user manual you'll find a chapter about the PID. You might want to read it. It goes into details.

BTW, I said "cold water inlet" but it is not exactly correct. The inlet pipe to the brew boiler passes through the steam boiler for pre heating and extra stabilization. So really, if the steam boiler is on, the inlet is hot water, if the steam boiler is off, the inlet is cold water... That would explain why you see higher temp at the display.

I wouldn't flush too much to heat up the group head because then you introduce too much new water into the boiler changing its temperature. Just flush before you grind and that's good enough. I would flush mine sometimes again if I get distracted and a few good minutes passed before I start the shot. But if I just grind and pull the shot, there's no need to re-flush.

Yeah, I know it has pre-infusion already - but I thought it was not bad to pre-infuse longer - it can only help right?

Depends what you mean by "help"? The longer the better is not always true. If you preinfuse longer, then you adjust everything according to how you pull your shot. Grind, timing, etc. I don't think it's better or worse, it's just what taste you are looking for and how you adjust the other factors to work with everything else you do.

Why start the shot from the beginning of pre-infusion if there is no pressure on the puck?

You start timing from the time the puck starts getting wet. It's what everyone else is doing and if you want to be on the same page with everybody else... LOL

Look at a professional machine that has variable pressure like the LM Strada or the Slayer. There is no On/Off switch. It goes from 0 to 9 and you can go slowly or fast on the way up and on the way down. So where would they start timing? There's no specific point that the pressure is "ON". So you start counting from the moment that the puck gets wet.

It doesn't mean that you stop the shot too soon or too late. It is just something that you factor in into your total timing. Nobody says that a shot must be 25 seconds. It can also be 35 or 40. It all depends on the final result in the cup and your taste. If you're pulling a restretto or lungo, the ground size, weight, etc. timing will change.

LaDan wrote:Yes, the 19*F offset is already programmed into the PID from the factory. You don't need to do anything about that. In the user manual you'll find a chapter about the PID. You might want to read it. It goes into details.

BTW, I said "cold water inlet" but it is not exactly correct. The inlet pipe to the brew boiler passes through the steam boiler for pre heating and extra stabilization. So really, if the steam boiler is on, the inlet is hot water, if the steam boiler is off, the inlet is cold water... That would explain why you see higher temp at the display.

I wouldn't flush too much to heat up the group head because then you introduce too much new water into the boiler changing its temperature. Just flush before you grind and that's good enough. I would flush mine sometimes again if I get distracted and a few good minutes passed before I start the shot. But if I just grind and pull the shot, there's no need to re-flush.

That clears it up, thanks!

LaDan wrote: You start timing from the time the puck starts getting wet. It's what everyone else is doing and if you want to be on the same page with everybody else... LOL

I'll give it a shot

LaDan wrote:
It doesn't mean that you stop the shot too soon or too late. It is just something that you factor in into your total timing. Nobody says that a shot must be 25 seconds. It can also be 35 or 40.

They don't? It seems to be a pretty consistent thought that a shot is 23-33 seconds..anytime I've ever gone outside that range the shot is disgusting, too bitter or sour. What roaster offers recommended brewing parameters less than 20 seconds or over 40?

LaDan wrote: It all depends on the final result in the cup and your taste. If you're pulling a restretto or lungo, the ground size, weight, etc. timing will change.

No doubt. One thing I have noticed: When I get the grind dialed in, regardless of the coffee, they all share a similar characteristic. The shots taste "light". A sort of lightness to them all, maybe even a muting of flavors.

Does doing a long pre-infusion have a common flavor profile? Either way, I'll start without pre-infusion manually and just let the machine do its thing. Do you manually pre-infuse at all or simply lock it in, run the pump and start your timer?

What roaster offers recommended brewing parameters less than 20 seconds or over 40?

I didn't say less than 20 or over 40?? I said that it can also go up to 35-40 seconds. But for example Blue Bottle roaster for their Hayes Valley Espresso pull 40 seconds at their roasting and espresso bar in Brooklyn. They recommend 35 seconds on their web site http://store.bluebottlecoffee.net/Detail.bok?no=10 , but they pull 40 seconds at their coffee shop. I asked the barista there myself, since I noticed that the time seemed to be long, and he confirmed that they do 40 seconds. I was only saying this in reference to when you start your timing. If you start counting only after 8 seconds of pre infusion, and you pull 25 seconds, you really had a 33 seconds shot. And if you pulled 30 seconds, you really had 38. If it tastes good, it all that matters. There's no reason to cut it 8 seconds earlier just to be in the "acceptable range", is what I'm trying to say.

Does doing a long pre-infusion have a common flavor profile? Either way, I'll start without pre-infusion manually and just let the machine do its thing. Do you manually pre-infuse at all or simply lock it in, run the pump and start your timer?

I don't know. I just start the shot. I tried a few times to pre infused manually and I came to the conclusion that I still have a lot to learn before I experiment with that. Maybe other, more experienced HB members can chime in on that.

But what l noticed is that after I dialed in my grinder and shots, and I could consistently produce the same flavors on the next and next cups, and I was happy with it, if I then tried to pre-infuse it ruined the flavor (no surprise there), but it was in an inconsistent way and I just gave up on trying to explore it further.

LaDan wrote:I didn't say less than 20 or over 40?

I understand. There are exceptions, but for the most part its within the range.

LaDan wrote:I don't know. I just start the shot. I tried a few times to pre infused manually and I came to the conclusion that I still have a lot to learn before I experiment with that. Maybe other, more experienced HB members can chime in on that.

But what l noticed is that after I dialed in my grinder and shots, and I could consistently produce the same flavors on the next and next cups, and I was happy with it, if I then tried to pre-infuse it ruined the flavor (no surprise there), but it was in an inconsistent way and I just gave up on trying to explore it further.

Interesting. I have had literally the exact opposite experience. Started manually pre-infusing, got virtually 100% consistency from shot to shot, then tried starting the shot without manual pre-infusion and didn't like the results. Regardless, I'll try it your way for the next week and see what happens.

You should really always EVER adjust by flavour. Why change your prep if it tastes great??

Going outside of stated parameters or 'espresso dogma' may lead you into an unbeaten path of treacherous terrain and sour sinkers, but it doesn't always. Different machines, climates, water hardness, grinders, pid offsets, etc. will make it so YOU have to be the judge of what your parameters should be for exceptional espresso preparation. Similar to the expression - Keep It Simple Stupid - in espresso we tend to ask - How did it taste? Worry only about your preparation if you don't like the flavour or your shot or you're unsatisfied with your consistency to prepare great shots. Master your machine and what you like in an espresso. Jim Schulman has posted a great guide or two on how to adjust your grind/dose/temperature to change shot character. I'd look into that for more insight than to start toying with different lengths of preinfusion.

Really do what makes you enjoy the hobby, but I say to use stated parameters as a guide and adjust accordingly.

For sure, I realize that, thanks for the thoughts. I am simply curious what other procedures people are using, so I can try them as alternatives to my own and experiment, so I'm with you .
I'm going to try no manual pre-infusion for the next week and see what I think.

I've easily been able to pour shots that have no bad flavors (sourness or bitterness), but honestly, going through 3 different coffees in the last 3 weeks, I notice once I dial them in, they share more characteristics than distinguishable ones. I don't know any other way to explain it except this strong "lightness" to every shot. I can certainly taste a difference between the coffees, but its this strong "lightness" that is the main thing I'm left with.

Metropolis Redline: VERY bright and I can mostly taste that merlot, wine flavor
Espresso Vivace Dolce: Biggest flavor I can taste is Cinnamon
Paradise Roasters Nuevo: Mostly woody

All brewed based on roasters recommended parameters.

Again, the clarity isn't that strong. While it lacks bad flavors like sourness and bitterness, the one distinct flavor is "lightness". Maybe I'm confusing this "lightness" with "muted"? I don't know.