According to the table here http://www.freshcoffeeshop.com/Coffee/e...ia-cremina the difference would be 4.5 °F (0.75 bar ~ 116.1 °C/241 °F)

Here is an image of the prototype temperature probe


Here is an image of how the data appears on screen. This can then be saved as an .xls or .csv file


The idea is to build a highly responsive probe that will fit a wide range of machines, that is non-destructive, other than drilling a hole in the centre of the bottom of the PF basket

Being a direct plug into a USB port it removes the need for a data logger, which to my mind is added expense. It reports in F or C by simply selecting within the software. It also works on a Mac which is relatively unusual

As it stands the probe is too thick to move quickly enough from ambient to operating temp, and there is no refined means of attaching it the the PF handle, other than adhesive tape, which is a bit primitive

The sampling rate is 10 times a second (10Hz)

I am concerned that moving to a fine probe like you guys have used will reduce its durability unless the probe tip could be replaced in some way

The probe also needs to be fine so the performance of the espresso extraction is not compromised

The bend in the probe is to prevent water from running back along the probe to the computer when in use

Im open to suggestions as Im no engineer and this project has been gathering dust for a while now

Reiss.

That's awesome! This would be great to have. If the metal was much shorter, and instead have wires, would it eliminate the problem of securing it to the pf? What about some high temperature-resistant, waterproof wiring for durability? Would this solve the temperature lag also?

Perhaps if you had a larger hole and a short, thin, high temp rubber sleeve that sealed it in the pf for purposes of it slipping out? Only 1/4" or so. The rubber sleeve would have to be slipped through the hole, and then the probe afterwards, this might work very well to keep it in place even with the long tube.

If that doesn't sound good, why don't you go with thinner tubing? Either thinner, or more conductive to heat, or both. Perhaps thin copper tubing? It would be flexible, and thus possibly less resilient, but the flexibility might be a good thing (i certainly wouldn't mind).

Nice post, Reiss. Thanks for alerting/reminding us of the products offered by that thermistor device manufacturer.

John - as you can (and have) imagined, there are multiple ways to accomplish a goal of measuring the temperature of water passing to or through ground espresso beans. To the extent that this temperature influences the taste of the product can be debated ad infinitum.

What is important is to come up with a TURNKEY product that anyone can easily use to improve the consistency of THEIR espresso under a reasonable array of THEIR operating cycles.

erics wrote:Sure, no charge , especially for all the work you did in creating this study - http://www.omega.com/ppt/pptsc.asp?ref=RLC-50&Nav=temf01

The part number for your desired range would be RLC-50-60/90-10 .

I'm also very interested in this one. Who of you have tried it and why don't we all use it? My Richard sticker ended up on the boiler for fun because on the group it can only show how burned my coffee will be.

KurtAugust wrote:I'm also very interested in this one. Who of you have tried it and why don't we all use it? M

I have that strip now for about two weeks and it is perfect range for Cremina. Works great. You pretty much keep the 176°F bar in green or unlit and if your machine is at about 0.7-0.8 bars you are good to go. Super easy.

I also attached Eric's small digital thermometer to group head to test it. It also works great and advantage is that it has digital temperature read-out which means it can be used on other levers where group-head temperature has good relation to brew temperature.

Both are good tools and I think Cremina should be shipped with either one of them

In case you missed it also check out Part 2 of my little study.