Hi all,

Quick question about Pid for Vetrano 2b. The default pid setting for temperature offset is 27 degrees( which is what CCS set it at)

I have read posts and have seen people change the offset.

My question is this: Why would someone want to change the default PID temperature offset? Shouldn't the default be correct?

Let's say the offset is 27 degrees from boiler to puck...why would someone want to change offset temp other than to confuse themselves lol.

I am not an expert, but this parameter seems to be one that should be left alone, no?

I welcome insight from fellow home baristas!

Every machine could be slightly different as are the rooms we use them in. People who change the settings often have other ways of measuring temperatures (Scace device) to get more accurate temperatures and settings for their machine and environment.

You could also use a simple Digital Thermometer with a thermocouple to roughly read the brew water temperature and adjust the offset.

spearfish25 wrote:Every machine could be slightly different as are the rooms we use them in. People who change the settings often have other ways of measuring temperatures (Scace device) to get more accurate temperatures and settings for their machine and environment.

This. At the end of the day the number doesn't matter as you're either going to increase or decrease it based on taste.

Additionally, it also depends on how you use the machine. I believe chris stated that they don't do a warm up flush. This means that if you do multiple shots in one session any subsequent shots will be too hot (at least over the set temp).

I own a QM67, which is also a double boiler machine from Quick Mill. When I first received mine, I had to change the offset a bit.
I based this on poor coffee taste across every coffee I was using, as well as what looked like very high readings from an Eric's thermometer in the brew head.

It's important to understand why there is an offset in the first place.

The PID is getting its temperature reading from a sensor in the brew boiler. There are pieces of tubing, usually copper or stainless, that run from the boiler to the E61 brew head.

A soon as the water leaves the boiler,
its temperature starts to drop, since the plumbing and the brew head are not insulated,
and have no independent source of heat.

Thus, to get the desired water temperature as the water hits the coffee, whatever that temperature may be,
the brew boiler is run at a somewhat hotter temperature.
This allows for the drop in water temperature as the water makes its way from the boiler to the coffee.
The amount of temperature loss from the boiler to the coffee can vary from one machine to another,
so that is one reason the offset is adjustable.

There is another factor at work here too.

Our machines have E61 style brew heads.
One feature of that design is that the brew water is always circulating slowly thru the body of the brew head.
This serves to keep the brew head hot, although at a somewhat lower temperature than the boiler.
That means that as you change the offset, you also change the temperature that the brew head sits at.
Best advice is to make small changes in offset, usually no more than 1 or 2 degrees at a time, and observer the results.
It's also good if you have a reliable way to measure the water temperature closer to the coffee.

I'm quite pleased with Eric's thermometer. It's not essential, but it helped me get things dialed in with a little less work. A Scace is great for measure temperature, but costs a lot more.

When you make a change to the offset, make sure to wait long enough for everything to stabilize, which could take up to an hour.
Also be aware the temperature of the room where the machine is located can become a factor,
if there are very large temperature swings thought the day. A couple of degrees is unlikely to matter.
You may feel an influence if your situation is a cold room early in the morning,
which then gets lots of sun at lunch time, and goes up by 15 or 20 degrees (F).

When you make a change to the offset, make sure to wait long enough for everything to stabilize, which could take up to an hour.

One hour is certainly at the extreme . . . just off the top of my head, I would say 15-20 minutes for any 1.0 degree set point change. I do not disagree with the one hour but it is long depending on the changes made.

Room temperature variances play a role also.

Wow, thank you guys so much

The coffee seems to taste good, I do drink it with steamed milk. Now, does it matter if you change the offset or the set temp? Just curious if it makes a difference.

Also, for Eric's thermometer, how many degrees off is that from the brew temp, for example. If the thermometer says 205, would the brew temp be 200, I think I read a while back that even though the probe is close to the brew head, its still going to cool down another several degrees in the inch or so from the probe.

Has anyone ever used an infrared thermometer to measure water temp at the screen? I'm not super technical, but want to make sure I am getting the best out of this beast of an espresso machine lol

thermocouple in the portafilter basket with proper resistance (aka a SCACE or some DIY version) is really the only way to know for sure. infrared doesn't work with water, as its reflective, based on my experiences (at least to any worthwhile accuracy).

Also, for Eric's thermometer, how many degrees off is that from the brew temp, . . .

It is about 3-5 degrees above the temperature presented to the coffee during the middle 2/3's of the brew cycle.

Did you not download the install manual?

I'm tempted to buy one eric lol. Yes, I saw several files from your link, but skimmed through it since I was working. Really cool thermometer, love the idea!