Astro Hacker News - Direct electrochemical black coffee quality appraisal using cyclic voltammetry

fsckboy |next [-]

>Here we show that cyclic voltammetry can be used without any additional sample preparation to directly measure the strength of a coffee beverage and, separately, how dark the coffee has been roasted; these two properties are implicated in the sensory profile of the beverage.

those two properties do not even touch on the quality of the beans, nor how those flavors are developed and maintained through roasting. measuring the darkness of roast does not tell you how dark the coffee should have been roasted for optimum flavor profile.

I'm not aware that it can be done analytically, it requires trained tastebuds, and in my experience, tastebuds trained on many coffees over time (a sort of 10,000 hours type idea, probably needs neuroplasticity); most roasters have a sort of narrow "tunnel vision" based around their own coffees which they taste relentlessly.

to actually taste delicious coffee it needs to cool down quite a bit, below 130F 55C which is not very hot. I understand the pleasure of a hot cup of coffee, but that pleasure is not flavor pleasure.

anon84873628 |root |parent |next [-]

Yes, but once your target roast and strength is dialed in, this can easily be used for quality control. Keep in mind that the coffee industry is very different than home specialty brews.

Xmd5a |root |parent |next |previous [-]

Isn't this whole approach to coffee similar to audiophily? I'm asking this as an avid coffee drinker (fancy grains, with a fancy machine) and an appreciator of headphones as well : when should one stop the quest for perfection? For headphones, anything beyond 400-500$ is not reasonable, since past this limit you start chasing gains that are barely perceptible or are a question of taste and you'll be able to find equivalent headphones that cost less.

Where do you draw the limit personally ?

Tade0 |root |parent |next [-]

My cousin bought a used professional coffee machine that looked like a piece of industrial equipment - tread plate and all.

Most of the time he would ask you if you want your coffee too sour or too bitter, but this one time he managed to get all the parameters so right, that he brewed something which tasted like thick, coffee soup.

Outright teleported me to 1960s São Paulo to which I've, BTW, never been.

I've been chasing this taste ever since, but my cousin still hasn't been able to repeat the feat.

fabian2k |root |parent |next |previous [-]

I have a 200 EUR handgrinder and an Aeropress. That's about the limit for me, there isn't really anything else to improve there for filter coffee. There's probably a lot more ways to make different coffee, but not that much room for making the same coffee better. I also don't want to mess with the water, so that puts a ceiling on coffee quality anyway.

There's some legitimate room to spend much more money when making Espresso. But a lot of the more expensive options would be more about the workflow than quality. If you need to make many Espressos in quick succession you'll hit the limits of cheaper equipment.

ricardobayes |root |parent |previous [-]

I think it's very comparable: the current dialogue in "coffee" circles revolve around the usage of "steamed water" that supposedly improves the taste. I remember similar discussions around cables in audio circles.

zimpenfish |root |parent |next [-]

> "steamed water" that supposedly improves the taste

If that's about americano, James Hoffmann[0] covered why this might be the case - normally you use the steam wand to provide the water for the americano but that water has been sitting in a tank being heated and cooled and gradually evaporating down to concentrate all the bad stuff. If you use the wand to steam fresh water, you don't get all the crud. Seems simple and logical enough.

[0] https://www.youtube.com/watch?v=0HdzJz_evNw (skip to about 5:00 for the explanation)

benj111 |root |parent |previous [-]

Well steamed water was a rabbit hole.

Although surely you would need to make the steam from steamed steam for optimal results?

TeMPOraL |root |parent [-]

> Although surely you would need to make the steam from steamed steam for optimal results?

Well, it's a complex question. I'd suggest to start from plotting your favorite coffee hardware brands and barista youtubers/tiktokers over the phase diagram of water, and continue from there.

Once you get comfortable with thinking about coffee in Scientific Terms, one avenue to explore is to try and embed the aforementioned phase/opinion water diagram plane into the larger Great Material Continuum hyperspace. To do that, you add a third axis: price (for hardware obviously by MSRP/catalog price; for vloggers, plot specific tips or steps by price of ingredients they use).

Having done that, you should have all the tools needed to make informed decisions in this space - just compare the paths water takes through this enriched 3D phase diagram as it turns into steam and then your beverage using any given method and combination of equipment :).

con-sulting |root |parent |previous [-]

Local brewhaus has a 145° steamed milk policy, just a better flavor experience at lower temps. Many coffee testers/flavor judgment use the various strange ways of drinking coffee in tiny flavorful sips. I couldn't be the coffee tester, but I enjoy the work they do.

zeristor |next |previous [-]

How long before James Hoffman finds out about this.

Waiting for him to appear in the YouTube shorts Brooklyn Coffee shop now I think about it.

SkiFreeWin3 |root |parent |next [-]

It took me a few vids to warm up to his presentation style and the production style, but now anyone else doing coffee vids seems like a total amateur/influencer/YT rusher. Early Hoffman coffee competitions were the proof point for me that he’s not simply an influencer entrant.

His presentation still is still a bit forced and orchestrated to me, but at least I believe he’s smart and has interest in the craft.

zimpenfish |root |parent |next [-]

> Early Hoffman coffee competitions were the proof point for me that he’s not simply an influencer entrant.

That and owning a coffee roasting company?

jitl |root |parent |previous [-]

he’s adorable what’s not to love??

zeristor |root |parent [-]

Is his quiff a side effect of his prodigious coffee intake?

I’m waiting for his eyes to glow blue, and he perfects the ability to fold space and time.

andreareina |root |parent |previous [-]

What does this offer over the refractometer he already has?

chronogram |root |parent [-]

It says that refraction does not cover everything.

> By sampling features in the electrochemical response that are affected by the ensemble chemical composition of the coffee rather than measuring the concentrations of individual molecules, this approach captures quantitative information about both roast color and beverage strength. These two properties drive the sensory profile of the beverage, thereby allowing this analytical technique to exceed the insights provided by refractive index measurements and provide additional quality information that correlate with flavor.

advisedwang |next |previous [-]

I suppose this might be useful for making full-auto coffee machines that can self-adjust parameters like grind size, water:coffee ratio, tamping strength (for espresso style machines) etc. Although there's plenty of things to measure already, they don't really directly check correct brewing. This could help improve a lot.

anon84873628 |next |previous [-]

From the lab of Christopher Henson at University of Oregon. They've done lots of work on coffee.

Doran and Chris also host a podcast called Coffee Literature Review, where they invite a guest from the coffee industry and discuss a scientific paper connected to coffee somehow: https://podcasts.apple.com/us/podcast/coffee-literature-revi...

At the SCA Expo a few years ago, they were doing electrochemistry on brewed coffee to measure caffeine content, and also change the flavor in weird ways. This latest paper seems to build on previous experiments in a similar vein: https://sca.coffee/sca-news/25/issue-18/amped-up-using-elect...

userbinator |next |previous [-]

I suggest "black coffee electrochemical quality appraisal"; as-is, it made me wonder what "electrochemical black coffee" is.

TeMPOraL |root |parent |next [-]

Technically, everything is electrochemical.

euroderf |root |parent |previous [-]

It has electrolytes!

s0rce |next |previous [-]

I sent this to our electrochemist at work, maybe if we have some time we can test the coffee in the breakroom.

xingped |root |parent |next [-]

The title says "quality" but the summary seems to say it only measures the "strength" oand "darkness of roast". Certainly won't measure how good it tastes. Given these are the two properties purportedly measured, I imagine you'd get the same results regardless of tastiness and age of the coffee or beans.

TeMPOraL |root |parent [-]

> Given these are the two properties purportedly measured, I imagine you'd get the same results regardless of tastiness and age of the coffee or beans.

Right, but another way of putting it, it might provide useful signal if you hold "age of the coffee or beans" and other such factors constant :).

anon84873628 |root |parent |previous [-]

Their lab has been playing with this for a while: https://sca.coffee/sca-news/25/issue-18/amped-up-using-elect...

camillomiller |next |previous [-]

* laughs in barely cleaned Italian moka *

RobotToaster |next |previous [-]

Amazing that the article describes what coffee is in detail, but never describes what "cyclic voltammetry" is.

For those who are as ignorant as I https://en.wikipedia.org/wiki/Cyclic_voltammetry

picsao |previous [-]

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