Peppersass wrote:I don't quite get what you're saying in the second sentence, so let me provide an example...

Bah! Sorry, I was heading to a meeting and apparently got in too much of a hurry to parse my thought out properly. I meant to say, "If his offset is -4°F, then the display (which is offset-adjusted) ought to be reading ~3°F lower than what the machine is delivering at the group, again as measured by the Scace device." So, pretty much what you describe.

Peppersass wrote:But here's a far more important question, Nicholas: how do you get those little degree symbols to display in your posts?

I'm on a Mac, so it's option-0. option-k/shift-option-8 delivers a similar one. On Windows, and for more discussion on the topic, see here.

Edit: also, you said:

Peppersass wrote:So, in the end, you probably have to do what shadowfax and tekomino did, and change the offset so you get the best shot when the displayed temperature is close to what roasters or reviewers with LM machines recommend.

I think you had it right the first time:

Peppersass wrote:The best advice I got was to treat the temperature as relative. Use the roaster's/reviewer's recommendation as a starting point and adjust the temperature for best taste.

I've had a number of times where my temperature preference is right in line with the suggestion/description of a coffee (within reason of course!). However, I've also had some pretty wonky temperature preferences. Using roaster recommendations to guess your offset is probably little more than an exercise in frustration unless you get lucky. Your 'best advice' above is the only way to optimize your shot temperature: learn how temperature changes impact shot character by experimentation, then use that to predict how to adjust your temperature.

shadowfax wrote:This is strange, but on the La Marzocco GS3 (and I assume the FB80/GB5 as well), the boiler set temperature is not offset-adjusted. When you switch to "editing" mode on it, you see the 'raw' temperature set value of the system, i.e. what it try to will match its raw thermocouple reading to. The offset is only applied on the displayed temperature in normal mode (i.e. when you're not editing temperatures). It's actually kind of convoluted and confusing, but there it is.

So when Dick is saying that the Scace reads ~0-1°F less than his set temperature, he means the raw reading, not the offset-adjusted one. The offset just makes the display read much lower than the temperature at the group.

That would make the GS3 one awesome machine! My offset is roughly 3f. That means I'm losing about 3 degrees from the boiler to the Scace. If I understand this correctly, you are losing only one!! And I've installed the Piero group cap which is essentially what you have. I don't have preheated brew water but that shouldn't affect what you are measuring. I'd be happy with what you have!!!!

mitch236 wrote:If I understand this correctly, you are losing only one!!

My offset is ~-3°F. Dick's, apparently, should be ~-1°F... maybe. I'm not totally sure what the best way to 'mononumerically' quantify what brew temperature is: The GS3 has a very distinctly slant-L profile, but the corner of the L is pretty rounded and the slant, as it were, is not exactly 90°. That is to say, brew temperature doesn't quite flat-line in a shot, it continues to rise, just very slowly. Do you average seconds 3-30? 10-30? I don't know that there's a standard that's strictly abided by, which just brings home the major shortcoming of "recommended brew temperatures." The important part is shot-to-shot consistency. It doesn't matter if your offset is -20F, like a lot of E61 double-boilers, as long as your brew temperature profile is consistent from shot-to-shot.

Working with the Scace device I've been able to attain a less than one degree variance in shot profile. Throwing out the first 3 seconds as Greg advises of course. I use roughly a 3 second open flush before brewing.

Hadn't viewed this thread for a while. The temperature offset is a little confusing as it is programmed. In terms of performance or quality the offset is meaningless. If I have a 5 degree offset and you have a 1 degree offset it means nothing more than they are different. The offset is there for 1 reason only. The reason is to have a display that actually displays the temperature of the exiting water from the group.
There are various reasons for this:
1. The place the temp is measured is different from the place the water exits.
2. Error exists in electronics. There is an adjustable resistor on the electronics board for calibration. This is completed in a controlled environment and done at a particular temperature. If you use in another temperature the temperature will most likely not be exactly the same. In general all electronic components (resistors, capacitors, temperature probes, etc.) have some tolerance of error associated with them.
3. Mechanical assembly. Heating element position, boiler rotation, welding differences all have some differences when assembled. This actually introduces some error as well.

Not sure why we never got the programming to apply the offset to both the set temperature and the display temp. Mostly is was a translation issue from English to Italian and in the end I did not win. The best advice to give anyone is that if the display temperature does not match the Scace device then I would adjust the offset until it does. Then if you want to raise the temp by 2 degrees, just set the temp higher by 2 degrees while disregarding the actual set temperature numbers. You probably have already figured this one out.