DiFluid R2 Extract and TI Scales - Espresso testing

DavecUK

been testing this setup for a while with brewed coffee and I did have some problems (of my own making). Once I stopped overthinking it and doing my “own” thing, the problems disappeared and I started getting results. Which show, I brew my coffee pretty much perfectly, something I had guessed already. I tried a few things and was able to brew imperfectly in both directions…to low/high an extraction % and the taste differences seemed to correspond.

With Espresso, I was a little more sceptical as Rodney from BB mentioned that they had not been able to get results anywhere near what they should be getting. I found this interesting and thought, OK this week I am going to try espresso. I had intended to try it yesterday and couldn’t log into the app, which had logged me out after a phone update. Plus horror of horrors, my email wasn’t recognised for password reset….none of them? The problem…I had never made an account, just used the app as a guest…and once I remembered this, I was “in like Flynn”. More good news, all my previous results were still saved in the app! Note to self, create an account some time.

Entered the app, switched the R2 refractometer and the TI scales on, Bluetooth immediately connected them to the app on. I quickly zeroed the R2 and was ready to go. I switched to espresso and started inputting to the app, I had not RTFM, but had learned my lesson…don’t fight the app.

Bodum espresso glass on scale (touched app to auto enter cup weight
18g of beans on scale (touched app to auto enter weight

There were other fields, but rather than mess with them…like shot ratio etc.., I thought, reasonably, the only data I have that makes sense is the weight of coffee and the weight of cup…everything else is down to the machine and when it auto releases. So bunged the scales and glass on the Evo 2 (my shot auto release pressure is at 7.4 bar). Set the app to the next option (record brew or shot process), touched app button it to tare the scales, pulled lever down and I was away.

The first drop hit the shot glass and the scale started recording and timing the entire process in the app. at around 1g per second, out came my espresso. At 35s the Evo2 auto released and the process ended. The scales of course didn’t stop and I didn’t think to stop them for a while. No problem though as the Evo not only had my shot time, but my preinfusion time as well.

Moved to analyse/show results and up came the familiar 3 by 3 grid. I figured I now needed to put the Espresso in the R2 for refractometry analysis. I want to make the point here, the R2 is absolutely the easiest refractometer I have ever used!

This is probably the only slightly involved bit for me as the sample has to be at room temp and I like my espresso hot. So this is how I do it. I use a printer refill syringe with it’s needle and a small glass dish they use for marmalade at posh hotels. The syringe allows me to take an espresso sample under the surface of the crema (saves me having to mix the crema in first. It also allows me to take a small sample, just enough for the refractometer and squirt it into the glass dish. This immediately brings it to room temp and I suck it back into the syringe (no bubbles) and squirt the blob onto the R2 sight glass. I press the R2 button and it starts taking readings (3 I think), I look dpown at the app and am gratified to see this:

Apparently 20% is meant to be perfect…so I wasn’t far off. I suppose I could tweak the grind, or the release time but to be honest it tasted great. As for tweaking grind or release time, not 100% sure what effect that would have, so I need to test a few more espressos, in case this was a fluke and then over the next weak or so, test what does what and by how much?

Here’s a bit more data it created on my shot….the time I input myself from the Evo…there is no place to add preinfusion time. Something they need to add to the app, as well as (for me), which machine, not just which grinder. For this I used the T64 (with SSP HU) from BB.

Then finally the equipment I personally use. Note the syringe for printer cartridge refilling and the glass dish.

Final thoughts, the software is good and does all the critical things well, but I think could use some tweaks, all cantered around recording grinder and machine better.…so I am going to feed back to them in the hope these can be included in a future update.

Hopefully you found this lengthy post interesting, I did, because I had never used a refractometer for espresso before..

MWJB

DavecUK Apparently 20% is meant to be perfect…so I wasn’t far off. I suppose I could tweak the grind, or the release time but to be honest it tasted great.

Just to note, 20% precisely is not meant to be perfect. it will shift slightly based on origin (some coffees can be over at 20%, others under). Normally, your average will be about 20% (maybe 19-21%, depending on protocol), You’ll still likely get good brews/shots at a slightly wider span.

DavecUK

MWJB Normally, your average will be about 20% (maybe 19-21%, depending on protocol), You’ll still likely get good brews/shots at a slightly wider span.

That I am sure is correct.

LMSC

Was the espresso tested as unfiltered?

DavecUK

LMSC Was the espresso tested as unfiltered?

Yes, you don’t need to filter is as far as the D2 instructions go.

JHCCoffee

Thorough review as usual, @DavecUK ; 🙏.

With my ancient VST, I had to, for each use session:

Clean the refractometer glass with distilled water at the same temperature as the room
Allow the unit and the glass to come to the same temperature as the the room
Verify the above with a thermocouple
Take a sample with a syringe and filter
Dilute the sample with distilled water, to an exact dilution ratio
Ensure that the diluted sample is at room temperature and at the same temperature as the glass, both of which must be in a tight range.
Use a clean syringe or a pipette to dispense drops of the sample onto the glass
Take 20 readings and calculate the average
Input the average into an EY% calculator, along with the other required data
Note the result

Which of the above 10 steps is eliminated by the R2? Needless to say, with my old VST refractometer (which co-incidentally was called an R2), I was not motivated to run TDS tests; just too much faff.

MWJB

JHCCoffee You wouldn’t need to do steps 3, 5, 8 even with a more modern (e.g. purchased in the last 11 or so years) VST like a Lab II, or Lab III, nor with the DiFluid. Not sure that steps 3 & 8 even appear in the Reichert R2 manual. You only needed to do step 5 because you are using a ‘coffee’ refractometer rather than an ‘espresso’ range refractometer.

A simpler, intuative way to calculate EY (especially for espresso) is to divide beverage weight by dose weight, then multiply by TDS:

e.g. 40g bev/18g dose = 2.22

2.22* 9%TDS = 20% EY.

You overlooked step 11, attribute a liking score to your brew, so that you can correlate how much you like it with EY. There’s little point in measuring EY without doing this (other than perhaps a quick, ball-park dial in, prior to fine tuning, if you can’t drink all the cups you make).

DavecUK

JHCCoffee I have resurrected my old camera, have to see how the batteries hold up, as my video device is my phone and of course, that’s running the app. I will then try and video the process. The only issue might be videoing invariably introduces extra work and awkwardness working around a camera…as my cameraman’s name is Mr Tripod, who is bulky and reluctant to move.

I suspect that’s the best way to show the realities of the device and it’s use with espresso/pourover I have always believed in you being in my kitchen, peering over my shoulder without fancy music, jump cuts and edits is the best way to understand the realities of owning and using something.

JHCCoffee

MWJB JHCCoffee You wouldn’t need to do steps 3, 5, 8 even with a more modern (e.g. purchased in the last 11 or so years) VST like a Lab II, or Lab III, nor with the DiFluid

You also have to calibrate it with distilled water (not sure how frequently). @DavecUK do you need to calibrate the R2?

Any sense ( @DavecUK or @MWJB ) how much time the R2 will save me, relative to my current Reichert, from commencement of setup to put away? I don’t do much refractometer testing due to the time it takes relative to time availability.

And .. what is the relative accuracy and consistency of the Reichert vs the R2? Any sense?

Finally @DavecUK I’ve read individual reviews. There are many reliability complaints (faulty units, etc), but many compliments about customer service and support. Any initial impressions about that?

I have not had any issues with my Difluid scale. And I like the firmware upgradability and app linkage of Difluid products, though I don’t really use the app (I rely on my Decent app).

dfk41

DavecUK Dave, if the camera holds up, along with your sanity, could you also show the brewed method? I have a set of these waiting for me to pluck up the courage to open them! I find the task more than a little daunting!

DavecUK

JHCCoffee You also have to calibrate it with distilled water (not sure how frequently). @DavecUK do you need to calibrate the R2?

You can calibrate with RO water, which is what I use. I calibrate each time because it only takes a few seconds, but I suspect it’s only necessary to calibrate once per day, especially if you put the R2 down in the same shaded place every time.

It’s very easy to use and I have had zero issues with reliability. The main issue I had was me fighting the app, because I thought I knew better…I didn’t. BT connectivity has also been exemplary.

MWJB

JHCCoffee All refractometers need zeroing with distilled water before each round of readings, or if you suspect the ambient temperature has changed over the course of testing (takes about a minute each time.

If you are prepped with a pipettes/droppers, a glass to cool the sample, and a syringe & filter (for espresso/areopress/french press/cupping), taking a reading is about 2min max.

We can’t test accuracy, but manufacturer’s figures are +/- 0.1%TDS (typical 0.05%TDS) for the Reichert R2 Coffee, +/-0.03%TDS for the DiFluid R2 & precision +/-0.02%TDS (no precision figs for Reichert). I found the R2 comparable to the VST Lab II coffee when compared for non-syringe filtered, V60 fllter coffee, using VST’s measuring procedure for both, details in a thread here that you actually started:

https://coffeetime.freeflarum.com/d/2078-easier-to-use-refractometer/35

simonc

JHCCoffee I’m having an issue with my microbalance scale at the moment and so far their support have been really supportive, once I found their email and stopped using discord.
Still to get to the solution but they are offering a plot of solutions do full marks so far.