For Alex Duetto owners, what offset do you find is most accurate? Mine came factory set at 18F but I was finding that setting the temp at 200 - 201f based on the recommended brew temp for the specific coffees I was using seemed to result in slightly ashy, bitter shots. Lowering to 197f - 198f immediately alleviated this, and the coffees immediately came to life, with the flavors that exactly matched the described flavor profile from the roaster. So, I'm suspecting that my offset may be set too high. I'm running both boilers and do a short 1 oz flush immediately before my shot, and a 45 min warm-up. Thanks for the input.

-kurt

Kurt - I don't know what 18f means (typo?) but mine came factory set at 93c = 199f.

Now before we start a massive discussion on temperature and whatnot , I found that the higher the dosing required a little higher temperature to go with it. I tend to go with a larger dose in a triple basket so I'll be anywhere from 18g to 20g a shot depending on the bean and my tastes. Therefore have I found that I needed to raise my temp by 1c so I'm now at 94c=201f.

From my understanding and what I interpreted from The Professionals Barista Handbook, lower doses require lower temps to bring out similar flavors in higher doses and higher temps.

So I think it really depends on what you dose and the bean and of course the most important item- your own taste! Your taste is what really should set the guideline for how you like to drink your coffee. . .

Javacat wrote:For Alex Duetto owners, what offset do you find is most accurate? Mine came factory set at 18F but I was finding that setting the temp at 200 - 201f based on the recommended brew temp for the specific coffees I was using seemed to result in slightly ashy, bitter shots. Lowering to 197f - 198f immediately alleviated this, and the coffees immediately came to life, with the flavors that exactly matched the described flavor profile from the roaster. So, I'm suspecting that my offset may be set too high. I'm running both boilers and do a short 1 oz flush immediately before my shot, and a 45 min warm-up. Thanks for the input.

-kurt

Mine came configured this way (+18 F) as well. I find brew temperature changes quite a bit based on ambient temperatures - as much as 3 or 4 degrees. I recall seeing a graph of these figures at some point but couldn't find it just now. Maybe someone else can provide the link? I find the 18 F offset seems to produce the PID temperature setting most accurately with a 60-70 F ambient temperature.

Mine is set up in my basement which is around 60-ish this time of year. The specific coffee that seemed to be the farthest off was Bella from Klatch. 5-days off roast. I dose in a LM double about 17g. On their website it recommends 201F. I get nothing but a bitter, flat shot at that temp, but 198F was a completely different story (did'n't have time to play around with it anymore). I do realize that recommended temps vary from machine to machine, and from one coffee to the next, etc. I just started to think that maybe when the machine was calibrated it wasn't allowed to warm-up sufficiently and that is why the offset seemed off. I've pulled many other coffees and honestly haven't had any that i've pulled over 199F that tasted good. I've found that they usually are best from 196-198F which is why I think that the offset is wrong. I've always believed that this was too cool. I don't have a scace so I'm just going by the comparisons of the roasters temp rec to my pallet so nothing scientific here, fyi.

IMO, brew offset on an e61 style thermosyphon is pure hubris unless the ambient conditions are invariant.
With the crazy weather in LA lately, the boiler temp has been adjusted up and down like a yo-yo.

Use Eric's thermometer adapter to adjust the boiler so the group idles ~196°F / 91°C [ or whatever floats your boat ]

EDIT :
The recommendation above is for 'typical' H-B style use of a shot or two every few hours, not back to back testing or production runs.

Same here... got with 18F offset, and for a while i kept PID at ~200...

It's only thanks to the training we get on this website to listen to our taste buds for adjustment, that i settled on 196 - 198 for most... sometimes even 194 with no sour notes.

Mine is 18deg, and I have tested the water temp with a thermocouple on and in coffee in the basket, and the temp is dead on..Early on there were some temp studies of this machine by Jim Gallt (pidkits) and I got the same results using coffee and a probe snaked in the basket...I actually run mine a couple degrees (203) hot with the roast I have been using for the last year. Every so often I play with the temps with new roasts because that "best temp" per roast does vary.
Cheers

I'm not sure why my coffee was tasting scorched before, but the last several days I've been pulling my shots at between 200-201 and the shots have been phenominal. The blend I had the most trouble pulling at higher temps was the Klatch Belle and even the lighter roasted Black cat. Still haven't pinpointed the issue but everything seems to be ok. I am playing around with a bit of a longer initial cooling flush after the 1 hour idle to try to stabilize everything. From what I've read though, not much of any flushing is required. I've been using about a 1-1/2oz flush and then pulling my shot around a minutes afterwards, and the machine seems quite happy with this.

Javacat wrote:I am playing around with a bit of a longer initial cooling flush after the 1 hour idle to try to stabilize everything. From what I've read though, not much of any flushing is required. I've been using about a 1-1/2oz flush and then pulling my shot around a minutes afterwards, and the machine seems quite happy with this.

If you look at a group thermometer, you see that a small flush has no effect on group temperature. It will drop back to whatever it was before flushing.

My Duetto has group idle temperature 4.5 - 5.0 C below the set temperature, when properly warmed up. It's easy to see when it is warmed up and sometimes I've tried to speed things up by flushing it. My observation has been that you have to flush a lot to make the group warm faster. Flushing does have an impact on boiler temperature, and flushing enough to make group warmer will hit boiler really hard. Hence, I think flushing has mostly a negative impact on temperature stability. Of course running a tiny bit of water to get loose grounds off the group head is a good idea.

As a side note, I still don't pull shots straight away when the machine has been idle. Instead I do a single shot first to remove stale coffee oils from the group. That has a noticeable impact on shot quality in my opinion. It is also a good way to use your sacrificial grounds from purging the grinder.