Measuring TDS for Espresso: To filter or not to filter - Page 3

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someguy12
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#21: Post by someguy12 »

shawndo wrote:Just a data point of questionable value...

I got a set of the red speeds last week. I mainly got them for the less static they are reported to have and did not expect any actual change in flavor. I've pulled more than a few shots on them now and I have to say they are actually noticeably different, flavor-wise, than the standard burrs. Not sure if its worth the $$ difference and I haven't had them long enough to say that they are generally "sweeter" or "greater separation of flavors" or whatever, but blends that I am familiar with (Hairbender and Full Cycle) tasted quite different and better.

I think I would have gotten them originally just 'cause they look cool, but I didn't know they were available at the time. I rationalized a spare set of burrs and got them afterwards. I usually keep an extra set of burrs around "just in case"
Shawn, I'm having the internal debate whether I should get red speeds. Did you notice a significant difference in terms of static (taste aside)? Were you able not to WDT/RDT after you got these good looking burrs? :D

Cheers!

michael
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#22: Post by michael »

Are the red speeds only available with the conical or can you also get them with the flat

When I got my mazzers a few years ago, everyone seemed to want a conical, but now the flats seem popular

Any reason you're not considering the flat 8)

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shawndo
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#23: Post by shawndo »

someguy12 wrote:Shawn, I'm having the internal debate whether I should get red speeds. Did you notice a significant difference in terms of static (taste aside)? Were you able not to WDT/RDT after you got these good looking burrs?

Cheers!
I can't say with certainty yet, but I'm leaning towards "it is less static than regulars, but the RDT is still way better".
like on a point scale, redspeeds maybe lowered the static 2-3 points, but RDT lowers it 10 points.
I think in general, you don't need to use WDT/RDT in either case, but it is better/consistent with it. Also, with RDT, i find I don't really need WDT because everything falls into a perfect little cone that can be tapped flat. (true for standard or redspeeds)

It will be a while before I am confident with that call because I somehow got the RDT into my muscle memory and keep forgetting to NOT use it. The problem now is that I just switched to a non standard roast (monsooned malabar SO) which seems to be above average with static compared to my usual hairbender. With this roast I am getting a lot of static on the regular and red speeds if I don't use RDT, so I'd like to reserve judgement until I get a regular roast back into the rotation.

Honestly though, if you're paying this much for a grinder a certain amount of rationality has already left the building... just get the red speeds!
michael wrote: When I got my mazzers a few years ago, everyone seemed to want a conical, but now the flats seem popular
Any reason you're not considering the flat
I'm old school and still think conical is where it's at :wink:
Darmok and Jalad at Tanagra

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Peppersass (original poster)
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#24: Post by Peppersass (original poster) »

ds wrote:I do not filter my espresso before I drink it so... You can't defeat data with words, only more data...
Shife wrote:To add to this, I'm having trouble wrapping my head around the idea that filtering the coffee would change the disparity in variation between the Robur and Monolith.
You guys need to read up on the science of espresso extraction. I recommend "Espresso Coffee - The Science of Quality", by Illy. It's a classic. You'll find more recent information on extraction and how to measure extraction yield in books by Scott Rao and Matt Perger, both of whom filter their espresso samples when taking readings with a refractometer.

Again, the undissolved solids can have a major impact on the %TDS reading without affecting flavor at all. This throws off the extraction yield calculation.

The whole point of measuring extraction yield is to determine how much of the flavor-producing compounds in the grounds has been dissolved by the hot water (i.e., has been literally extracted from the grounds). There's a direct correlation between this and the sour-bitter balance, which is critical to achieving the best flavor. It's balance we're after, not "more is better".

In contrast, the undissolved particles are basically tiny broken bean particles and dust that make it through the portafilter holes. They have no effect on the sour-bitter balance, which is what the extraction yield is intended to measure. For example, 14% EY is going to taste really sour. 25% EY is likely to taste really bitter.

By adding the undissolved particles to the %TDS measurement, the extraction yield is increased without altering the sour-bitter balance. Put another way, your reading isn't telling you anything about where you are on the flavor curve because you're including a bunch of stuff that has no affect on taste.

Another problem is that we want to use %TDS as a measure of strength. The undissolved solids may affect your perception of body and creaminess, but they don't have anything to do with your perception of strength. It's the concentration of the dissolved compounds (and the sensitivity of your taste buds) that determine your perception of the strength. By adding the undissolved solids to the %TDS reading, you throw off the measurement of strength (i.e., the coffee measures stronger than it really is.) You can prove this by tasting French Press or espresso coffee, then running it through a filter and tasting again. While much of the body may be gone, the strength will be the same.

Now, as to whether filtering will narrow the difference between the Monolith and Robur, I don't know. That's a guess on my part. It's possible that the Monolith produces a lot more very fine particles which make it into the cup as undissolved solids. It's also possible that the Robur's production of very fine particles (undissolved solids) isn't as stable as the Monolith. Again, I don't really know.

It's worth repeating the experiment with filtered samples for two reasons. First, it might shed some light on why the two grinders differ so much in extraction yield. Second, and more important, the results reported earlier are misleading: they show a high extraction yield for the Monolith, but that number has been boosted by undissolved solids. Not only could this be overstating the Monolith's capabilities, the measurements cannot be compared with others who filter their samples before measuring extraction yield. That would include many leading coffee experts, many world-class baristas, many roasters, many cafes and many home users.

I think if you read the above carefully, you'll wonder how Socractic and Atago could have come to the conclusion that it doesn't matter if you don't filter espresso samples.

samuellaw178
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#25: Post by samuellaw178 »

Peppersass wrote:Again, the undissolved solids can have a major impact on the %TDS reading without affecting flavor at all.
Dick, I've mentioned this and it may have been missed - undissolved fines affect <0.5% of TDS in my limited tests (2 separate data point of 0.4% and 0.39% TDS reduction from Robur E) and similarly from one other person that I've asked. Have you done pre-filter or post-filter experiments to come to that conclusion?

Mrboots2u
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#26: Post by Mrboots2u replying to samuellaw178 »

Hi I have found that randomly you get outliers as results that are more than 0.5 tds , so while its ball park , I have found it's not an accurate or reliable way of measuring tds as a result .

ds
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#27: Post by ds »

Peppersass wrote:You guys need to read up on the science of espresso extraction. I recommend "Espresso Coffee - The Science of Quality", by Illy. It's a classic. You'll find more recent information on extraction and how to measure extraction yield in books by Scott Rao and Matt Perger, both of whom filter their espresso samples when taking readings with a refractometer.

Again, the undissolved solids can have a major impact on the %TDS reading without affecting flavor at all. This throws off the extraction yield calculation.
Says who? Surely you can point us to study with data that supports that conclusion? And if you cannot, there is your hypothesis so you can design your own experiment to prove it or disprove it. Again, data not words.
Peppersass wrote: In contrast, the undissolved particles are basically tiny broken bean particles and dust that make it through the portafilter holes. They have no effect on the sour-bitter balance, which is what the extraction yield is intended to measure. For example, 14% EY is going to taste really sour. 25% EY is likely to taste really bitter.
I will point again to study with data from Socratic Coffee, Exploring the Impact of Particles on Espresso Extraction, I will quote bottom line:
SocraticCoffee wrote:Bottom line

Based on our data, given a standard espresso setup, particle size alone did not systematically predict espresso extraction (TDS/extraction yield). A larger range of particle size variability led to increased extraction. Further, particle size did significantly impact overall shot time (i.e., smaller particles led to longer extraction time); however, the placement of smaller particles within an espresso puck did not lead to significant differences in shot time or extraction.
I have emphasized relevant part.
Peppersass wrote: Now, as to whether filtering will narrow the difference between the Monolith and Robur, I don't know. That's a guess on my part. It's possible that the Monolith produces a lot more very fine particles which make it into the cup as undissolved solids. It's also possible that the Robur's production of very fine particles (undissolved solids) isn't as stable as the Monolith. Again, I don't really know.
I think keyword here is that you don't really know, so why even say it? According to Socratic Coffee study I have linked to previously and I quote:
SocraticCoffee wrote:Looking more closely at the effects of particle uniformity and size, contrasts between conditions revealed significantly lower TDS from particles of 177-250 µm compared to 250-300 µm and control (p=0.00), but not compared to the 50/50 mix of the two particle stratifications (p=0.08).
Which blows hole in your argument since they find that smaller particles result in lower TDS. Again quoting findings:
SocraticCoffee wrote: Uniformity of particles did have a significant effect. Smaller particles led to less TDS.
So that would actually indicate that Monolith produced more uniformity of particles thus would explain having higher TDS.

Shife
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#28: Post by Shife »

Peppersass wrote:You guys need to read up on the science of espresso extraction.
No... You need to explain how filtering the solution would change the large disparity in variance coming from the Robur. Hint - Only one grinder showed large variation. Am I expected to believe that filtering the solution, which is not how I would drink it anyway, would suddenly even up the results? Unfiltered, one grinder showed consistent and repeatable numbers. The other did not. What are you intending to show with the filter?

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dominico
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#29: Post by dominico »

This topic is split from the KafaTek Monolith 68mm conical single-doser thread, starting with vberch's post comparing TDS measurements between the Monolith and a Robur.

The original post was left in the thread to preserve continuity.
vberch wrote: Over the last four days I had a privilege to compare my friend's Monolith (Rob, thank you very much!) to my Robur-E side by side using three different coffees.



Parameters:

All the shots were pulled on Faema Lambro with IMS dispersion screen and naked portafilter with VST 15gr basket. Grinders were dialed-in to produce the same flow using the same coffee. Grinder chutes were brushed between each shot and flushed with three coffee beans and cleaned again. Dose, Preinfusion and Tamping Pressure were kept constant. Dispersion screen was cleaned between sessions. 33 shots were measured using an Atago refractometer paired with a VST app and over 40 shots were analyzed by taste. I took pictures of every shot, refractometer reading as well as VST app reading. Coffees used were Ethiopia Shaye Ayra, Ethiopia Sidamo Watadara and Brazil Fazenda Sao Dominos.



Results:





One of the puck stacks from day 3:



Conclusion:

I pulled anything from very tight ristrettos ('0' mark on Monolith and one number from burr rub on Robur) to doubles and Monolith outperformed Robur-E by 3.1% of extraction yield in doubles and 2.1% of extraction yield in ristrettoes as well as by taste. Notice Monolith shot to shot consistency. Not a single shot from Monolith was under 20% EY for doubles while Robur shots ranged from 15.7% to 21.3%. This is a huge spread.

To me, it was liberating to set aside the refractometer and just taste the shots. There was no comparison. Monolith shots were sweeter, rounder and less edgier. Even the shots with the same or very close extraction yield were much tastier from Monolith. The best way for me to describe the difference is to make an analogy with Scotch. Monolith to Robur is like a 12 year old Scotch to an 18 year old Scotch. Both are wonderful and share the same taste profile, but an 18 year old is much more pleasant and complete with less harshness. This is aside from the fact that Monolith was more consistent, was easier to use and was much more quieter.

I love my Robur-E and it is a great grinder and by far the best grinder I've had after owning a Compak K10, E10, Super Jolly, etc. Monolith is the better grinder. It is easier to use at home, it is easier to clean, it is quieter, it consistently produces higher extraction yield shots, makes beautiful fluffy grinds AND pulls tastier shots.

I am done. I am going to sleep for a week.

A few random pictures for your viewing pleasure:











https://bit.ly/3N1bhPR
Il caffè è un piacere, se non è buono che piacere è?

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