HB wrote:What is this thing called? The Greg Scace Device? The Scace Portafilter Thermometry Device? The Thing that Barry Carried Around the Conference Ticking Off Espresso Equipment Manufacturers? Whatever you call it, please welcome guest reviewer Bob Yellin! He will lead the discussion and I will chime in Bob's commentary with my own observations comparing it to my "dinky TC" (Abe's words, who will also join the review). Thanks to Terry Z for supplying "the device" to HB.

Update: Added thermofilter instructions and WBC procedures.

Part 1

This will be a review of Greg Scace's Espresso Machine Thermofilter Temperature Device (known hereafter in this review as "TTD"). This device is a "snap-in" basket for an espresso machine "chopped portafilter" and measures the temperature of water directly out of the brew head. I will post the review in installments over a period of about two weeks, but if there are questions or comments along the way, please feel free to post them.

I used an Extech 421508 digital thermometer to measure and data-log the temperatures. The Extech has a resolution of 0.1 deg F and an accuracy of ±(0.05% reading + 0.6 deg F). The QuickMill Andreja Premium E-61 HX espresso machine was the "test bed".

To begin the process, I photographed the device and measured vigorously boiling water. Water at my altitude (about 500 feet) boils at 211.1 deg F. The TTD measurement showed the boiling water to be 211.2 deg F. I also checked temperatures against a NIST-calibrated standard digital thermometer, down to about 180 deg F (the range of interest) and there was never more than a 0.5 deg F difference between the TTD and the standard. Very impressive!!

In the next installment I will discuss the construction of the device and my initial impression of it "as received".

Photos of the device are available in other places but there are some differences between them and this, the "production" version. So here are some shots of the TTD:

How much is the actual temperature display.... (not included in the price)

just curious... and how IMPORTANT is this upgrade....

Please give opinions... (or is this not the place for this)

It depends. With a $10 thermocouple and $12 basket you can make a "schomer device," drill a hole in the basket, epoxy in the TC, fill it with coffee, and measure while you brew. So the real question is what is gained by Greg's set up.

First and foremost -- repeatability between shots and people measuring. Every Schomer basket is unique, every fill and tamp is too. So using the same basket will let you know if the water is getting into the coffee at the right 1C or so range ballpark, but no more. Using different baskets on different machines will tell you very little -- the position of the TC is critical when it comes to measuring how quick the machine gets up to temp, etc etc.

With interest now in 0.1C accuracies in shots, and in characterizing how fast a shot settles, or what the temperature profile during the shot is, the required accuracy and repeatability are ratcheted up, and the Schomer basket is in beyond its depth. Greg's device is the first attempt to meet that need for more accurate measurement. Greg is a NIST scientist and espresso machine expert, so no better person is even imaginable to design this "next step" in thermometry.

There is a steep price rise when going to measuring gear that is one magnitude more accurate. This is true of voltmeters (not readout accuracy, but real accuracy), gauges, or anything else. To get that extra decimal point in repeatable espresso measures requires a big step up from drilling a hole and epoxying in a TC. Whether that extra effort is worth it in your practice is for you to decide.

HB wrote:What is this thing called? The Greg Scace Device? The Scace Portafilter Thermometry Device? The Thing that Barry Carried Around the SCAA Conference Ticking Off Espresso Equipment Manufacturers?

Pity Greg doesn't work for the German TUV. Then it would be the
Druckkaffeetemperaturmessungseinlage.

Of course, if Greg were German then he wouldn't sell it, he'd just write the spec:
Druckkaffeetemperaturmessungseinlagebestimmung

another_jim wrote:There is a steep price rise when going to measuring gear that is one magnitude more accurate. This is true of voltmeters (not readout accuracy, but real accuracy), gauges, or anything else. To get that extra decimal point in repeatable espresso measures requires a big step up from drilling a hole and epoxying in a TC. Whether that extra effort is worth it in your practice is for you to decide.

I'd also like to add that it turns what used to be a real pain in the yass measurement into a completely trivial exercise. No more packing coffee around fragile thermocouple wire. No more snaking wire up through baskets or over basket lips. Just pop it in and go to war. The amount of real good data you can get in a very short time is pretty mind blowing. With Schomer's method, or other methods of snaking thermocouple wire inside the pf, you couldn't make continuous duty cycle measurements because of the time required to set up each run. Now you can map out machine performance from intermittent duty to complete full-on, line out the door and into the street, panic mode continuous shot pulling. Not that I have any interest in this of course.

-Greg

Oh, yeah. to clutter this up further, another cool thing that is now possible is to use the portafilter as a training tool. It's really easy to get feedback on flushing and rinsing techniques. If you are learning a new machine you can sort it out very quickly. It's also now possible for a shop or a coffeegeek to actually run some sort of quality control program in which the brew temp got measured once a day, which means that a shop can stay on top of changes in machines over time. Makes diagnosis of temperature related problems real simple. Also makes machine replacement easy because you can quickly dial in the brew temp of the replacement.

I hope these points resonate with machine techs and shop owners who I think will really benefit from this.

-Greg

Greg,

Since you already have a flow adjusting valve on it, adding a pressure gauge would have been nice. Perhaps for your next upgrade?

Sorry not to have posted the entire review in one shot but I have house guests and full days with them until late next week so I'll be posting this piece-meal. Most of the raw data is collected. It just has to be written up. It will include charts of data, comparisons with other measurement methods and lots more.

As far as flow rate is concerned, I believe it is fixed, or at least it is recommended that it stay as received. But Greg can correct me on this if necessary. Here is a quote from an email to me from Greg (with his permission, I hope). I noticed that the flowrate gave me between 2.25 and 2.5 oz in 25 seconds.

gscace wrote:I suppose I need to clarify this for everyone, but the reason that the flowrate is a little higher than you think it ought to be is because the coffee cake absorbs water that you don't see in the shot, but which passes through the group. We measured the water uptake of a bunch of shots (well actually Barry did the measurements), and the value is about equal to the amount of coffee in the pf. So the 2.5 ounce number is actually just a shade shy at 25 seconds. The Italian standard is for 30 secs extraction and the WBC standard is as well, so the volume collected that you see will be very close to right at 30 secs. Should be around 76 ml at 30 secs.

I hope to have the next installment tomorrow if I can lose my grandchildren for more than 10 minutes!

BobY