Scace Device vs Styro Cup method

Tips and Tricks you have discovered with your S1, VII, Mini-VII, Dream, or Dream T that lets you do any aspect of coffee making, steaming, maintenance, etc better.
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JohnB

Scace Device vs Styro Cup method

Post by JohnB »

After verifying the accuracy of my K type thermocouple, the Scace & the Fluke in K & T mode I did a number of back to back tests today comparing both testing methods. Using a cut down styro cup in the p/f & a k type thermocouple I was able to come within a couple tenths of a degree Celcius of the same readings taken with the Scace w/T type.

In each case the P/F w/Scace or the P/F w/styro was installed & left for 30-60 minutes. Then a series of 4 flushes were pulled & measured. I did several different temp tests using CC's method of removing the p/f for 30 seconds between flushes & several where I just dumped the water left in the Scace/cup. Sometimes the K/styro readout was a couple tenths higher, sometimes a few tenths lower but certainly close enough to tell you if your offset is correct or needs adjusting. The key is to do the ice water/ corrected boiling distilled water calibration so you know that your meter/thermocouple is correct or so you can offset the difference when you take readings.

The cup used had a small drain hole in the bottom & the thermocouple was inserted from the side so that the end was not touching the inside of the cup. It was cut down so that the bottom of the cup protruded far enough to insert the t/c & the top was flush with the p/f.
RapidCoffee

Re: Scace Device vs Styro Cup method

Post by RapidCoffee »

Wow, that is remarkable accuracy for such a relatively inexpensive method of measuring brew temp. I concur on the importance of calibration, it was the first thing we did with every thermometer when I worked in a biochem lab. May I assume you adjusted the hole in the bottom of the styro cup to get a flow rate similar to a double espresso pour (~2ml/sec)?
JohnB

Re: Scace Device vs Styro Cup method

Post by JohnB »

RapidCoffee wrote:Wow, that is remarkable accuracy for such a relatively inexpensive method of measuring brew temp. I concur on the importance of calibration, it was the first thing we did with every thermometer when I worked in a biochem lab. May I assume you adjusted the hole in the bottom of the styro cup to get a flow rate similar to a double espresso pour (~2ml/sec)?
Unfortunately that really isn't possible with a styrofoam cup bottom getting nailed with 9bars of pressure. Make the hole as small as you want & the 2 oz of water will still blow through in 9-10 seconds plus there will be leakage where the thermocouple goes in. With the Scace the same amount of water takes 16 seconds so neither method accurately mimics a 25 second pour. This is most definitely not a very scientific comparison but it is the way most non uber geeks would be doing the styro test & the results are amazingly close to each other. I just did a retest after leaving the scace in the machine long enough to fully warm up & did one flush before testing. The next flush brought me up to 92.1C with the machine set to 92C. I immediately swapped in the styro cup/k set up & did a 3rd flush which recorded 92.3c.

I imagine its the time/water difference between the 2 test methods that makes it work. If the water was flowing through the styro cup at the same rate as the scace I'm betting the cup method would read much hotter. The faster flow compensates for the lack of mass in the cup vs the scace??

Let me just add that I don't consider the styro cup test a suitable replacement for a Scace Device if you are setting your offset. I would only recommend it as a method to determine if you "need" to buy/rent/borrow a Scace to accurately set up your machine.
Last edited by JohnB on Sat Feb 28, 2009 12:34 pm, edited 1 time in total.
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chas
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Re: Scace Device vs Styro Cup method

Post by chas »

John, it sounded like perhaps you did some tests both with taking out the PF between tests ala the CC method and with just leaving the PF in between tests. When I did that, I noticed that the temp was more repeatable and stable on the test I did with taking the PF out between tests which mimics actual operation. Did you see that as well?
Chas
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JohnB

Re: Scace Device vs Styro Cup method

Post by JohnB »

chas wrote:John, it sounded like perhaps you did some tests both with taking out the PF between tests ala the CC method and with just leaving the PF in between tests. When I did that, I noticed that the temp was more repeatable and stable on the test I did with taking the PF out between tests which mimics actual operation. Did you see that as well?
I did try the CC method where the p/f sits on the tray for 30 seconds & I did some tests where I remove the p/f briefly, replace it, remove it briefly again 30 seconds later & then back on. This more accurately mimics my practice of pulling a flush, removing the basket/drying/dosing & reinstalling in the p/f which stays mounted during the dosing. Alternatively I will also dose into a warm basket from the cup warmer leaving the p/f w/basket mounted until I swap baskets. Since I'm setting up my machine I concentrated on how I use it as opposed to the p/f off method so I'd have to revisit both methods to give you an accurate answer. I also wasn't really concerned with doing 4- 5 flushes in sequence although I did do a few that way. 95% of the time I'm walking up to an idle machine, pulling a flush & then making one shot so I want the second pull to be up to temp.

I'll take more notes & compare the different methods more accurately next week. This weekend I am back to drinking shots before my Pt's Sidamo goes by. :lol:
Weska

Re: Scace Device vs Styro Cup method

Post by Weska »

JohnB, thank you for your work on this. It's good to know that there is a rough-and-ready substitute for Scace readings.
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chas
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Re: Scace Device vs Styro Cup method

Post by chas »

On a related note, how the hell do you pronounce Scace anyway?
Chas
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JohnB

Re: Scace Device vs Styro Cup method

Post by JohnB »

One other thing I should mention about the styro cup readings is that you "would probably/might" get different results on a Mini because of the vibe pump. My tests were done at 9 bar on the S1 & from what I've read the vibe pump builds pressure slower & might be set higher so the water/thermocouple contact period would most likely be different. Of course if the Scace test ran longer also it might balance out or possibly the higher(?) pressure of the vibe might compensate for the difference. No idea so Mini owners are on their own as far as comparing the two test methods goes.
Richard

Re: Scace Device vs Styro Cup method

Post by Richard »

chas wrote:On a related note, how the hell do you pronounce Scace anyway?
I heard someone who knows Greg Scace pronounce it SKAY-see, but that's only anecdotal. Ask him?
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Re: Scace Device vs Styro Cup method

Post by michael »

how do you calibrate the scace/fluke 8)
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sakurama
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Re: Scace Device vs Styro Cup method

Post by sakurama »

Put the Scace (not the Fluke!) into a bath of water and ice - lots of ice. Alternatively you can put the Scace into a pot of water at a rolling boil. Just the business end - not the handle. The readings should be 0° and 100°C. They were when I sent it off to you so there's not really any reason they should have changed. If you changed the thermocouple type they might be off but I wrote the type on the plug and made sure it was set to T before I sent it off.

Did it work out for you?
_ _ _ _ _ _ _ _ _ _ _ _ _ _
www.gregorhalenda.com
JohnB

Re: Scace Device vs Styro Cup method

Post by JohnB »

sakurama wrote:Put the Scace (not the Fluke!) into a bath of water and ice - lots of ice. Alternatively you can put the Scace into a pot of water at a rolling boil. Just the business end - not the handle. The readings should be 0° and 100°C. They were when I sent it off to you so there's not really any reason they should have changed. If you changed the thermocouple type they might be off but I wrote the type on the plug and made sure it was set to T before I sent it off.

Did it work out for you?
That should be boiling distilled water & you need to correct the boiling temp for your elevation(topo sites) & atmospheric pressure(that day/WeatherChannel.com) or your numbers are worthless. Greg specifies suspending the scace in the steam over the boiling water using a tall slim container so the steam is funneled into the scace. I'd definitely suggest doing both tests although the boiling water would be a must considering the temp range you will be measuring.
Endo

Re: Scace Device vs Styro Cup method

Post by Endo »

You can use this website to correct:

http://www.csgnetwork.com/h2oboilcalc.html
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