Comments on: ExtractMojo

By: scott

scott — Thu, 06 May 2010 17:50:17 +0000

Impressed by the timely responses!!! Surely, I WAS in the wrong mode.
Shoot… I’ll add more to this shortly.

By: VinceF

VinceF — Thu, 06 May 2010 17:26:25 +0000

Hi Scott:

Tried calling you today on another topic, but you were buried with training, and apparently this problem. Sounds like your refractometer is in the nD (native) mode. Native Mode reads out the actual Refractive Index and TEMP of the sample/prism. You may use that mode, if you prefer, but you have to enter those values into either ExtractMoJo v2.0 or MoJoToGo for the iPhone, which uses those values to compute the % TDS.

To read COFFEE TDS Directly on the refractometer, punch the “Mode” Button until you see nothing in the top-right display, which is % TDS. When in the Native Mode, Coffee ranges from about 1.3330 (pure water) to about 1.3356 (1.50% TDS) at approx 20 Deg C. You can use Native mode to read Espresso (1.3601 @ 20 Deg C = 15.0% TDS, w/o buying another instrument, by entering the nD and TEMP into the iPhone or eMoJo v2.0 APPs.

Hope this helps, but feel free to phone me for more detail, left a number with your ADMIN staff. Best,

Vince

By: Paul Stack

Paul Stack — Thu, 06 May 2010 17:22:15 +0000

Scott,
You are in the wrong mode. Your methodology is fine – simply scroll thru the modes until the top line shows battery power, temperature and nothing else. You are in either nD mode (refractive index) or TC nD mode – temperature corrected mode.
hope it helps.

By: scott lucey

scott lucey — Thu, 06 May 2010 17:10:03 +0000

Cripes! No matter what I do I’m getting the same reading. I know for a fact I should be getting different readings and am even intentionally over/under extracting just to try and get a different read.
1.33 1.33 1.33. . . I’m going back to read the manual, as I should but first I want to post a brief synopsis of my understanding and a couple of questions.

1) clean w/ alcohol – do this between every sample
2) calibrate with distilled water – also between every sample – holding cal and read buttons until END shows
3) apply sample of coffee, let a couple of minutes pass so sensor and coffee equilibrate.
4) clean, repeat.

Onward I go to the manual – let me know if I’m F-ing anything up with my 4 steps.
Thanks

By: AndyS

AndyS — Sat, 01 May 2010 00:51:25 +0000

Lately my samples have been in the range of 17-21C (63-70F), depending on the room temperature. But it doesn’t really make much difference; as long as the liquid and the refractometer are close in temperature when the liquid is poured on the prism, they’ll quickly equilibrate and the instrument will be able to get an accurate read.

By: Scott Lucey

Scott Lucey — Sat, 01 May 2010 00:24:13 +0000

Thanks Andy, this helps a lot. What is the average temperature of your samples… I’ve been around 70 F…

By: AndyS

AndyS — Fri, 30 Apr 2010 02:11:44 +0000

Scott: There’s no need to wait a long time for samples to cool. Use one of those flexible plastic eyedropper/pipette thingies to transfer a few ml out of your cup into a room temperature demitasse. Place a cover on it if you wish (to prevent evaporation), swirl a bit, and within a minute or two the sample will be cooled close to room temperature. After you add the cooled sample to the well on your refractometer, wait another minute or two for the prism and the liquid to equalize in temperature. Then take your reading.

The instrument is temperature compensated over a fairly wide range, but the prism and sample liquid must be at the same temp.

By: scott lucey

scott lucey — Thu, 29 Apr 2010 14:50:10 +0000

finally i’m diving into using this! – i’m curious to know how sensitive the temperature of the sample taken is… we’ve been waiting for coffee to get to room temp (matching the temp of water calibration) – so i’m curious to know if you’ve compared day old samples to ones more fresh. this element of waiting for samples to get to room temp is the least enjoyable – i wonder if you prefer to brew various batches with various variables en mass, let’s say 5 or 10 at once. or if you’re strict on a one at a time method.

surely more questions will arise once i keep testing this device out.
tis wonderful though!

By: MoJoToGo Calculates Extraction Yield on Your iPhone | ShotZombies.com

MoJoToGo Calculates Extraction Yield on Your iPhone | ShotZombies.com — Wed, 07 Apr 2010 15:17:22 +0000

[...] you’re not sure why you need to MoJo your brew, James Hoffmann explains why you’re lazy, and his recent Flickr upload suggests that he’ll likely update that sentiment soon. [...]

By: Jim Cleaves

Jim Cleaves — Tue, 20 Oct 2009 17:17:53 +0000

We have been using the ExtractMojo software and both the filter coffee and espresso refractometers for several months in our R&D labs. We have found that the refractometers provide significantly more consistently accurate readings than the TDS meters we used to use.