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## Maths Zeroes in on Perfect Cup of Coffee (bbc.com) 162

One coffee drinker's perfect brew may be another drinker's battery acid. For this reason, and presumably others, mathematicians are zeroing in on the equations behind the taste of drip coffee. From a report on BBC:Composed of over 1,800 chemical components, coffee is one of the most widely consumed drinks in the world. The work by Kevin Moroney at the University of Limerick, William Lee at the University of Portsmouth and others offers a better understanding of the parameters that influence the final product. It had previously been known that grinding beans too finely could result in coffee that is over-extracted and very bitter. On the other hand not grinding them enough can make the end result too watery. "What our work has done is take that [observation] and made it quantitative," said Dr Lee. "So now, rather than just saying: 'I need to make [the grains] a bit bigger,' I can say: 'I want this much coffee coming out of the beans, this is exactly the size [of grain] I should aim for." Dr Lee says he sets his grinder to the largest setting. By doing so, he says: "The grains are a bit larger than you get in the standard grind, which makes the coffee less bitter. Partly because it's adjusting that trade-off between the stuff coming out of the surface and stuff coming out of the interior. When things are larger, you're decreasing the overall surface area of the system. "Also, the water flows more quickly through a coffee bed of large grains, because the water's spending less time in contact with the coffee, helping reduce the amount of extraction too. "If it's bitter, it's because you're increasing the amount of surface area in the grains. Also, when the grains are very small, it's hard for the water to slide between them, so the water is spending a lot more time moving through the grains -- giving it more time for the coffee to go out of solution."
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## Maths Zeroes in on Perfect Cup of Coffee

• #### So just what's "Perfect", then? (Score:1)

Can their "perfect" cup of coffee do this [girlgeniusonline.com]?

I thought not.

Dan Aris

• #### Drip Coffee? (Score:4, Insightful)

on Wednesday November 16, 2016 @01:10PM (#53297715)
Why study taste using the worst preparation method? Drip coffee taste awful.
• #### Re: (Score:3)

You can modify the drip method in various ways such that it's to whatever preference you may like...unless you like percolated coffee, in which case you are a monster. But yeah, I love my french press.
• #### Re: (Score:2)

You can get percolated taste from a drip coffee maker. Just run it through twice or three times (same grounds) until you get your desired level of nasty. Helps to use a non-paper filter.

Yes I knew someone who did this. Called it 'atomic coffee', didn't even realize it was basically percolator coffee.

That coffee maker was never right again.

• #### Re: (Score:2)

That coffee maker was never right again.

You can say that again! My brother-in-law ruined a pretty good coffee maker of mine that way. Thankfully, I was able to stop him before he tried to do the same thing with the espresso machine. My wife revoked his coffee-making privileges after that.

• #### Re: (Score:1)

by Anonymous Coward

We're reaching audiophile levels of absurdity when it comes to coffee preparation methods. I shouldn't have to do chemistry in order to drink coffee.

• #### Re: (Score:3)

We're reaching audiophile levels of absurdity when it comes to coffee preparation methods. I shouldn't have to do chemistry in order to drink coffee.

I don't know that anyone is suggesting that you have to "do chemistry" to drink coffee. If anything, at first glance, the approach from TFA sounds like a much more rational idea than advocated by many coffee aficionados (whom, I agree, can take this stuff to crazy levels).

I don't know the details, but it sounds like a really basic model that should be able to generate a basic table or something -- i.e., grind size X will have effect Y on coffee output, extraction time, perhaps component balance, etc.

Th

• #### Re: (Score:2)

Well, I found the original article here [siam.org]. After skimming the PDF, it looks like they spent a whole bunch of time playing around with complex diffusion equations to model a very basic drip coffee setup. As they note in their conclusion, actually applying this model to actual drip coffee machines (which have various input methods for water), not to mention the varying geometry of drip coffee brewing apparatuses, would require a lot more complexity.

So, I still don't quite get what the big deal is, since thi

• #### Re: (Score:3)

So this is the "spherical cows" of coffee, then?

• #### Re: (Score:2)

But you see, the marketing departments of the wine and audio companies were already full up with marketers who turned fermented grape juice into something special and mere cables into active hifi components. All the new marketing grads had to go somewhere.

What's next? Socks? Forks and spoons? Bath soap? Dish soap?

• #### Re: (Score:2)

Hello new friend-of-mine, you'll probably appreciate the conversation we're having below: https://science.slashdot.org/c... [slashdot.org]
• #### Re: (Score:2)

most likely because drip is the mot common brewing method?
• #### Re:Drip Coffee? (Score:4, Insightful)

on Wednesday November 16, 2016 @04:04PM (#53299633)

I have a French press, an automatic drip, and an espresso machine. I like all of them, and the fancy strikes me for different styles at different times. The automatic drip is my usual choice when I want to drink a whole bunch of coffee over the duration of a morning. Your user ID is lower than mine - surely you are too old for these hipster pissing contests? Just drink what you like.

• #### Re:Drip Coffee? (Score:5, Funny)

on Thursday November 17, 2016 @07:49AM (#53304509)

Your user ID is lower than mine - surely you are too old for these hipster pissing contests? Just drink what you like.

He was having hipster pissing contests before it was cool.

• #### Perfection in an imperfect world (Score:5, Funny)

on Wednesday November 16, 2016 @01:12PM (#53297735)

I mostly work from home and I brew a 6 cup pot of coffee almost every day, I put in two scoops (which are roughly equivalent to 1 heaping tablespoon) and it got me thinking about a month ago what the actual coffee to water ratio was supposed to be.

I found this chart (or one like it) https://blackbearcoffee.com/re... [blackbearcoffee.com]

Tried it out and my god, if that's the actual ratio I'm surprised most people can't see through time. I'll stick with my weak brew... if anything to ensure my particles don't vibrate through the fabric of reality

• #### Re: (Score:2)

That is the exact chart I use. 1.13 oz of coffee and 18oz of water in my drip machine. I also use light roast beans that I grind fresh.

I did try a dark roast that I like in my french press and it was way too oily and bitter for my tastes. So don't forget which beans you are using

• #### Re: (Score:1)

I usually go with about half of what that chart shows, and even that gets me pretty jittery sometimes. I'm no coffee connoisseur though, that's for sure. Usually just trying to warm up and/or wake up.
• #### Re: (Score:2)

I don't know about seeing through time. But if you can see the sun's glow through a pot of coffee, it's just barely colored water and should be poured out. Translucent coffee is for children.

You're not making it strong unless the plunger of the French press won't go all the way down.

• #### Re: (Score:3)

Funny you should say that, I'm the exact same way. Two scoops to 6 cups. I took a 'coffee appreciation' class that I got as a gift and discovered that I've been making my coffee really REALLY weak. I've tried to brew it to the recommended strength, but I find that I don't like it that strong. That's probably why I can drink so much coffee a day (two to three pots) and I'm perfectly fine. If I drank that much of the 'normal' strength I'd probably be jittery and irritable (well more irritable than I norma
• #### 'Drip coffee' != 'perfect' no matter how you do it (Score:5, Insightful)

on Wednesday November 16, 2016 @01:13PM (#53297751) Journal
Drip coffee is crap, plain and simple. You want decent-tasting coffee? Use a press instead. With drip coffee, the oils that make it taste really good end up floating on top and don't get down into the pot, are wasted, and you get inferior-tasting brew. With a press, you get everything the grounds have to offer, resulting in a richer, more complex, better-tasting brew. Yes, it takes longer (8 minutes plus prep time) but if you want to not waste perfectly good (and expensive) coffee, then that's what it takes to get the most out of it.

You're welcome. :-)

• #### Re: (Score:1)

by Anonymous Coward

Drip coffee is WAY better.

• #### Re: (Score:2)

I actually prefer my Keurig
• #### Re: (Score:2)

Tastes like plastic to me.

• #### Re: (Score:3)

You're not supposed to put the cup into your grinder.

• #### Re: (Score:3)

K-cups

In an age where we're trying to promote reusability and recycling and reduce waste, Your K-cups are a throwback, they're a waste of money, and you have little control over how your coffee is made.

• #### Re: (Score:2)

Drip coffee lacks the grit that you get in an espresso. The texture of drip is as boring as tea, it comes out as brown hot water.

• #### Re: (Score:2)

Loose leaf tea gets you more texture/sediment than bagged.
• #### Re: (Score:2)

depends on how you filter the loose leaf tea. I definitely get almost zero sediment with a high quality whole leaf such as white silver needle tea (Bai Hao Yinzhen White Tea). Tea that is cut or broken would leave more sediment in there, and a pot with a traditional filter would allow some smaller pieces through. I typically brew in a pot with a stainless steel wire filter, and I would not normally pour the sediment into a person's cup.

• #### Re: (Score:2)

depends on how you filter the loose leaf tea.

Depends more on the tea. If you're using fannings or broken leaves, then sure, you'll get sediment. If you're using whole-leaf, not as much, though the tendency for breakage depends on processing and drying.

I definitely get almost zero sediment with a high quality whole leaf such as white silver needle tea (Bai Hao Yinzhen White Tea).

Yeah, when you're using a style of tea that's minimally processed and dried directly (white tea) and specifically hand-plucked for large whole leaves (silver needle), then yeah, you won't get sediment. If you have a more heavily processed whole-leaf tea (e.g., most black teas) that go through a lot mo

• #### Re: (Score:2)

But it's usually just brown water with sediment, not a thick sludge like coffee.

• #### Re: (Score:2)

Use a metal filter in the drip maker.

It's still not great, but most of the oils you are missing are trapped by the paper filter more than just 'floating on top'.

There are people who hate the bitter and add paper to press like methods. You can also get wimpy coffee out of a press by cutting the steep time. A 90 second steep and the coffee might as well be decaf.

• #### Re: (Score:2)

I have a drip coffee maker in it's box in the closet that came with a metal filter. Still inferior to the press method IMNSHO.
• #### Re: (Score:3)

You can also get wimpy coffee out of a press by cutting the steep time.

No kidding, that's why I said 8 minutes steep time. Any more than that does you no good, any less than that and you're not getting the most out of the grounds.

There are people who hate the bitter and add paper to press like methods.

Those are people who probably don't really like coffee that much in the first place. They should stick to light roast, or just make tea. Keep in mind the average person doesn't know really good coffee from a hole in the ground, they only notice when it's really, really bad; the average person also drinks a 'coffee-like beverage' that is little more th

• #### Re: (Score:2)

Have you ever actually TASTED that foam floating on top? It tastes like motor oil.
• #### Re: (Score:2)

Have you ever just eaten a mouth full of salt? Taking a flavour in isolation to determine if it is a good component of a final product is just utterly stupid.

• #### Re: (Score:2)

try an Aeropress... great coffee

• #### Re: (Score:2)

Once you go Aeropress, you'll never settle for less
• #### Re: (Score:2)

I was at a clients a couple of years ago and they had an espresso machine. I was so impressed with the ease of use/quality I ordered one. I threw out my drip machine a week or so later as I could not go back. The prices on the machines have come down so while I still view it as a luxury, its not that much of a luxury. I think 500 buys the non-fancy version of the one I got. There are a plethora of models.

• #### What about Cold Coffee? (Score:1)

As an avid home cold brewer (24 hour cold brew steel filter, Tim Hortons Coffee) Why does the perfect cup have to be drip xd
• #### I like my coffee (Score:2)

I like my coffee like I like my women, freshly ground and hard pressed.

• #### Re: (Score:3)

I was waiting for this thread. I like it hot, strong, and bitter, and available on most NYC street corners for under five dollars.

• #### Re: (Score:3)

I like it just a little bitter, loaded with Irish whiskey and covered in whipped cream.

• #### Coffee taste is Subjective. End of story. (Score:5, Insightful)

on Wednesday November 16, 2016 @01:26PM (#53297929)

Arguing how to make the "perfect" cup of coffee is like trying to convince the world what makes up the "perfect" soulmate.

If there's anything to be extracted from Starbucks here, it's that "perfect" coffee is as subjective as the justification behind their insane menu options.

Pointless bullshit surveys are pointless. You probably won't even be able to convince a large enough test group to validate the results anyway, and bringing math into the equation is as useless as bringing math into the bedroom.

• #### Re: (Score:2)

I came to say pretty much the same thing. This is completely subjective. :)
• #### Re: (Score:2)

Pointless bullshit surveys are pointless.

Are you talking about TFA at all? There was no "survey" here. And, as usual, the media headline exaggerates the research and distorts it. The original paper makes no claim about the "perfect" coffee, only modeling some of the extraction rates and coffee concentration (which they claim is related to "quality" but they don't describe that any further or specify which is "better").

You probably won't even be able to convince a large enough test group to validate the results anyway, and bringing math into the equation is as useless as bringing math into the bedroom.

I already linked the original article above and discussed it a bit. Frankly, this "study" sounds like what would happen if you

• #### Re: (Score:2)

Frankly, this "study" sounds like what would happen if you took a couple beginning grad students in chemical engineering and put them in a room where they were so tired and caffeine deprived they started applying their diffusion models and mass transfer to coffee... and then a math grad student walked in and said, "Hey -- let's not use the numerical approximations... I can do some fancier symbolic stuff and get some cooler equations."

Frankly, this sounds like a couple of bean suckers got higher than giraffe pussy one afternoon, and came up with this brain-baked nonsense to waste a few hours.

• #### Re: (Score:2)

Except that most people will have certain things they want and others that they don't want. For example you may have a high tolerance for astringency as long as the coffee is strong; or you may not mind burnt notes as long as it has caramelized sweetness. But if you don't handle the coffee carefully you'll get a mish-mash of flavor notes that's bound to have something you don't like: burnt AND watery for example. Those don't normally go together, but it's certainly possible to produce a cup of coffee that

• #### Great job mathematicians (Score:2)

You've successfully done the exact same thing that food-scientists have been doing for decades! That or the BBC managed to completely miss the point of the original publication.....Just checked. Yeah, BBC didn't get this at ALL. http://epubs.siam.org/doi/abs/... [siam.org]
• #### Petroleum Engineering FTW! (Score:2, Informative)

by Anonymous Coward

Interesting. This is a classic example of Darcy's law (fluid flow in porous media). Coffee is a classic dual-porosity system. First, you have to model the flow through the intra-granular pores in the coffee grounds and the removal of water soluble and hydrophobic compounds (i.e. "oils") from the grain surfaces. Then you also need to model the water imbibition into the grains and the transport of the same compounds to the surface of the grains. What a fun twist on petroleum reservoir simulation. Yeah, I've w

• #### A dash will do you (maybe a pinch) (Score:2)

Whatever method you use to brew coffee, if bitterness is a concern, add a dash of salt (of a pinch in a french press) to smooth out the bitterness, a trick that's been around since ancient Egypt times (because they brewed with brackish water most likely).
• #### Re: (Score:2)

Ancient Egypt? Really? Professor Wikipedia had this to say: "The earliest substantiated evidence of either coffee drinking or knowledge of the coffee tree is from the 15th century, in the Sufi monasteries of Yemen."

• #### Re: (Score:2)

I've seen stories back to the 9th century. There has been some thinking that in Egypt they made a drink that used the coffee tree and a salty water. Supposedly that's where the idea of using salt to knock down the bitterness of the coffee came from. Regardless, it does work.
• #### Math will let us.... (Score:4, Funny)

on Wednesday November 16, 2016 @02:01PM (#53298337)

brew a cup that is almost, but not quite, entirely unlike coffee

• #### percolator is best (Score:2)

Either a percolator or a moka pot is my preference over drip. I would be interested in finding the ideal parameters for that. Temperature (boiling at my altitude is about the only option), time, grind, etc.

• #### Math singular. WTF (Score:2)

is wrong with people who are incapable of using American orthography on an an American site. Oh wait...it's msmash.
• #### Aeropress FTW (Score:2)

15g coffee per cup, 190F water, stir, press. Enjoy. Repeat as desired.

• #### Exterior vs Interior (Score:2)

Why are they making the distinction between the exterior of the grain and interior? The exterior was interior just prior to meeting the grinder... That is silly Math Profs or not.

You are try to find the golden zone

http://cdn.shopify.com/s/files... [shopify.com]

• #### FTFY... (Score:3)

on Wednesday November 16, 2016 @02:18PM (#53298571)

Composed of over 1,800 chemical components, coffee is one of the most widely consumed psychoactive drugs in the world

• #### Re: (Score:2)

Coffee is not a psychoactive drug, but one of those 1800 chemical components is.

If you're going to fix something it may help to actually get it right.

• #### Well duh. (Score:2)

Who doesn't know that you need to have the right grind size for your brewing method? The physics and chemistry of brewing of course is complex, but from a user standpoint for any given variety of coffee you only have two to four parameters to vary: the size of the grounds, the amount of coffee grounds per cup, (sometimes) the temperature of the water, and (sometimes) the brewing time. Since you judge the results subjectively, you just have to experiment a bit and find what you like.

Now here's something you

• #### Fellow humans (Score:2)

Can we all admit that coffee tastes awful?
• #### Equivalence theorem? (Score:4, Funny)

on Wednesday November 16, 2016 @02:58PM (#53299021)

Given: A mathematician is a machine for converting coffee into theorems.

We have now demonstrated: A mathematician is a machine for converting theorems into coffee.

• #### How to brew coffee .. it's the water (Score:2)

The TL;DR of coffee:
Brewing: Use a water with a minimum mineral content of 150-200 ppm (250-300 ppm is my preference).
Espresso: Use R.O. water or distilled water.

As always the bean and roast is part of the interaction as well so your mineral content and roast level are not completely independant.

http://www.thecoffeebrewers.co... [thecoffeebrewers.com]

FYI: Starbucks uses purified water for both espresso and drip in order to control for flavor. So when at Starbucks, avoid the drip and get an Americano

• #### Um, no. (Score:2)

Quality beans that are properly roasted should never result in bitter coffee, regardless of the grain size. If your coffee is bitter it's because it's poor quality or burnt.

• #### All beans and consumers equal? (Score:2)

This seems to consider all beans — and all consumers — are equal. Some people feel bitter less than others...
• #### I got sick. Now I don't like coffee (Score:2)

Coffee used to be one of my 3 major food groups. About 2 months ago I got food poisoning and spent 10 days with diarrhea. After several rounds of tests and delays, I tested positive for blastocystis [mayoclinic.org]. The first antibiotic was a joke. I eventually ended up on Metronidazole [wikipedia.org]; another antibiotic but a real kick-ass. Since I got off that (2 wks ago) the smell and taste of coffee is different and frankly, bad. I think whatever made me sick, or maybe the antibiotic, messed up my gut microbiome and altered my s

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