HOWTO Make a perfect cup of coffee -- the science of ferocious black madness

Salim sez, "Professor Mark Miodownik of Kings College Materials Research Group teaches us how to process raw beans to a perfect cup of coffee using every day using a collection of household & DIY implements." This was amazing -- I've always wondered about the chemistry of espresso and coffee roasting -- I've become a total coffee bore since I got serious about my home apparatus, and this has armed me with many useful factoids for understanding the imperfections in the shots I pull. Also, he uses Monmouth beans, which are all we use at home. They are superb. Dr Mark Miodownik - How to Make The Perfect Cup Of Coffee (Thanks, Salim!)


  1. Stop posting inane coffee stuff. I’m allergic, and hate the smell. So it’s not just that I don’t care about coffee, I actively despise it.

  2. Schwal, stop reading the coffee stuff. It’s irritating to hear that you are displeased by it. I love coffee and really enjoy writing and reading about it, and knowing that I cause you displeasure breaks my heart. My life would be so much simpler and more pleasant if only you would learn to use your spacebar.

    Or to visit another website.


  3. Schwal: I do pity you! Coffee is one of the finer things in life, often the only reason to get up after a big night or on a cold morning (well, that work and making money stuff has it’s own impetus).

    I assume your displeasure has evolved from the allergy – what reactions do you get? Is it just the smell or a result of imbibing?

    Also: just STFU and move on. Scrolling is easier than reading, last time I checked. At the very least, share your experience, don’t go throwing commands around like a douche. I’m now genuinely intrigued (and mortified) as to what being allergic to coffee would be like.

  4. I don’t know. A good coffee experience is much more than the chemistry of roasting and brewing after all, and requires a certain social interaction with other coffee lovers that’s hard to replicate at home. A cup of coffee can’t be perfect perfect without a pretentious jackhole telling me that the way I am about to drink it is Seriously Not Cool.

  5. I don´t think you are allergic to coffee, Schwal. Did your allergologist test you?
    Not liking coffee though, is a different, albeit strange matter.

  6. Schwal, Maybe you were mistakenly thinking that Cory was writing on boing2 just for you?

    Cory, please don’t stop writing about coffee. I am myself a coffee enthusiast, to the point that I blend and roast my own coffee (using a HotTop roaster)!

    Also, you should really consider upgrading your machine ;) KitchenAid is a very nice looking machine, but for the money you can get many that are so much better ;)

    Check out (great forum and good reviews, both from users and the pros) – Great forum: – European coffee forum: :)

    Now I am going downstairs to make a nice cup of Kenya Gethumbwini using the AeroPress (no espressomachine at work)…

  7. Nowhere near “First post!”…, but I soldier on:

    1a) Re.: the Reg Barber tamper: flat or curved bottom? I went for curved because I could see the mechanical reason why it might help pack the coffee down.

    Hmm? Um, you move the tamper’s handle in a circle (like a spinning top’s prescession) so that a smaller area of the tamper is pressing down on the coffee, increasing the PSI on a smaller area.

    1b) Hey all the whiners out in the other older ‘Tamper’ thread:
    How many hand-made tools are there where you can get the absolute very best of its kind (according to professional/competetive baristas – Who don’t need a thermometer to tell when the milk is boiled, unlike the yobs at Starbucks), at under a hundred bucks? Did I mention their hand-made!

    2) I could never understand why someone would want to ruin a perfectly good cup of coffee/espresso or a perfectly good shot of whiskey by combining the two together. However, I’ve only have good things to say about drinking espresso and grappa together.

    3) Monmouth beans: Fair Trade? Shade grown? Are you roasting beans yet? Me? Yup, outside, even in February, after brushing the snow off of the patio deck. Surprisingly, -25degC weather only adds about one or two minutes to the sixteen minute roasting time. However, the beans do cool down much faster, a bonus.

    4) I’ve D/L’ed the Monmouth catalog: I’m curious to see if some of their beans come from the same places as Just Us!’s coffees.

  8. For my money a litle one cup stove top or plunger is, well.. for my money. I’d love to be in a position to indulge this sort of obsession with my coffee.

  9. Thanks Cory. I’ll need to find a patch of time to listen, but this does look awesome.


    OK, I’ll sit down and be quiet now.

  10. JBang: Stove tops are great Although it’s not “real” espresso, it’s can still make an amazing cup of coffee!
    As for plunger, you should consider an AeroPress. It’s cheap and it makes an awesome clean, smooth cup of coffee!

  11. I have tried so many ways of making it, but I’ve settled on the #2 cone filter one-cup-at-a-time method. Half of coffee drinking, as with any drug use, is the ritual. Some of us are just more OCD about it.

  12. I like strong coffee – so I use instant. Folgers, to be precise.

    I agree with several of the posters about this overblown geekiness with regard to having $100 coffee tampers, $1000 grinders, roasting at home, and then the machine itself. This is ridiculous! Why not find a good coffee shop and “share” all this stuff with the other customers?

    Does it really make sense to have all this expensive STUFF to make your coffee? At some point this STUFF becomes as ridiculous as $500 monster cables for your stereo.

    On topic, if you can’t stomach instant, the cone filter method is a good second best.

    However, true purists invest in a greenhouse which includes an artificial sun and imported dirt, as well as a climate system so that you can create the exact conditions necessary for the perfect beans. Then you take your donkey through the greenhouse to pick the beans…

  13. Here’s the secret to a perfect cup of coffee, in four easy steps:

    1. Use some method to create a cup of coffee.
    2. Enjoy that cup of coffee in the presence of someone who uses a different method.
    3. “Oh, you’re still using [your method]? Only [my method] makes real coffee. As opposed to the kiddie stuff, I mean. I wouldn’t touch that other swill at gunpoint. Are you sure you’re not weak in the head? Intellectually, I mean.”
    4. Repeat, using that person’s method in step 1. Bonus points if they arrived at their method “scientifically!” or with the help of a device that requires its own special import license.

    Incidentally, the above method can be adapted to shaving, operating a stereo, and several other things lots of people do every day but worry that they could be doing better.

  14. In the future, Boing Boing will only post about the things you like. I guarantee it.

    (Sometimes I feel like a tour bus operator whose clients occasionally stand up in the middle of a trip, screaming and flapping at the other passengers that they are offended, yet bored by the things they’re seeing out the window. There’s a door. There are other buses!)

  15. Coffee is fine to post about and quite entertaining.

    Just don’t get me started on all that steampunk nonsense lol

  16. I’m detecting skepticism and a good deal of negativity about the complexities of roasting and brewing coffee (#1, #8, #16, #17, #18). It really is a complex process, and one can get a much better bean by investing care and effort into all stages. For the skeptics: Have any of you tried freshly (as in within one day) roasted beans? It sure is easy to ridicule things you know nothing about.

    #16: If you RTFA (or listen, rather) he’s talking about how to do it well on the cheap.

    This was a great find Cory. Thank you! I was glad to hear about Mayard reactions. He rambles a bit, but it was very informative.

    Oops, my coffee is ready. I’ll be nicer in a few minutes.

  17. I need to listen to this, but, I hope it does not only talk about espresso coffee as their is a lot of other ways to brew a good cup of coffee.

    Personally for me I like a French Press as its simple, cheap and quick yet provides a good full body cup of coffee. If I want to go something “exotic” then its off to the stove and Turkish coffee, but that can get messy.

    As for people going all nuts saying its too much for coffee, well, with everything in life sometimes people just want “the best”. Why do you buy that 50k car when that 14k car will server you well? Why are you buying a Mac when you can pick up a PC at half the cost? Its people money, let them spend it as they see fit.

    Personal, coffee to me is my wine as I dont drink. So when I see someone spending $100 on a bottle that will last them a night, I have no problem spending that on a grinder that might last me more then a few months.

  18. Durnit, can’t watch vids at work. Well, I post on /. occasionally, so I know how to post without RTFA, so I’ll give it a shot anyway.

    My search for “the perfect cup” involves more than just flavor. I make my coffee in the morning, so convenience and speed are essential as well. Grinding the beans the night before is nigh-on mandatory if I don’t want to wake my daughter and the rest of the family who get to sleep in (grumble). (Cory, if you don’t mind my asking, if you grind in the AM, how do you avoid waking Poesy if she’s not already up by then?) In the summer, a way to make iced drinks is essential as well, so I’ve been focusing on espresso as an iced Americano is easy to make.

    The Filtron I have is great for making thick cold coffee extract to store in the fridge, but it is cumbersome in our cramped kitchen and the flask of extract does not fit well in our over-crowded fridge. That and the prospect of spilling a full pound of wet coffee grounds isn’t very fun to contemplate. Otherwise it’s usually auto-drip coffee for hot drinks. The French press sees occasional use, but so far I’ve not been able to discern a flavor difference vs. auto-drip (same beans/grind) that is worth the extra time in the morning. I also have an Aerolatte milk frother that does a decent job with microwaved milk when I’m willing to spend a bit of time assembling my coffee. I like to use brown sugar in the milk for tasty foam. Not totally sold on foam in a travel-mug though as it tends to lead to thinking the coffee is cooler than it really is, and getting a burnt tongue once the hot liquid gets past the cooler foam!

    Here is a patent that may link (in the prior art section) to the Illy “pressure pod” espresso machine patent that I’ve been stalking ever since I found out about their new machine. The Illy machine uses a new sort of coffee pod that can hold pressure for a while before a valve (or bursting membrane) opens, spraying the espresso against a plastic surface. The result is purported to be an extremely good cup of espresso, with crema that is thick and lasts 30 minutes or more. I’ve been looking for the patent because the machines are $600-$1,000 US and require the patented Illy pods to function. If I find the patent, I find the desired pressures, which allows me to make a simple pressure-release valve to add to my existing espresso machine for potentially improved flavor at minimal cost.

    I found the Aerobie press somewhere in my searching as well. It’s only $25, but I already own (counts on fingers) four (auto-drip, manual steam-boiler espresso, French press, Filtron) dedicated coffee-making appliances. (The aerolatte also works for hot chocolate, so it doesn’t really count…) Given the current financial times, I can’t justify just buying a new dedicated coffee appliance, especially since my current ones have little or no resale value to offset a new purchase. I can, however, justify some bits and pieces and a threading die to modify my existing espresso machine in a non-destructive way to try and make it both easier to use and have a better-tasting product. That’s a hobby project, and I’m sorely lacking in those!

    If I do figure it out succesfully, I’ll be sure to write it up and either do an Instructable or get it to MAKE Magazine or wherever, as well as send a link Cory’s way.

    Anyone else have pointers to either the Illy machine or pod patent? I need desired grind, water and/or gas pressure, infusion time and water temperature at a minimum. Pressure ramp-up is a plus, as is detail on the surface the pressurized espresso hits to foam up a good crema. Not that I’ll notice the crema once I’ve obliterated it with ice and/or milk, but it is supposed to make the espresso taste better.

  19. I had absolutely no idea about the spacebar. I’ve always been a scroll-wheel guy. I like the spacebar though. Now I can zip through pages like… like I’ve had a lot of coffee.

  20. @ #16 I live about 15 miles from the closest decent coffee shop. I’ve got a high-end burr grinder and a damn fine espresso machine (all hail Mr. Giotto!) because it’s the most practical way to get a great espresso drink given where I live.

  21. schwal@1: In addition to being allergic to coffee, you are also allergic to your own behavior. That’s a real drag.

  22. Best, of course, would be Steampunk style coffee equipment. Some of the higher-end espresso machines do approach this lofty goal, with their use of brass and what-not (and of course their actual functional use of steam). Such a machine should be wirelessly controllable (across the “Ether”) by a Steampunk mod of an iPhone or netbook.

  23. Beyond a proper tamping and good pressure, I don’t care how fancy a machine you have, using good, fresh beans is the only “secret” to good coffee. That’s it. There is no “secret”. Good quality fresh coffee beans make good coffee. End of story. The tech behind it means nothing if you’re using crap coffee.

    Now, if you want a “Maker” style of coffee making, you can get into home roasting, and a good source for green coffee. But really, unless you’re going to apprentice to a real roast master, you’re not going to make much of a difference. So buy good fresh whole bean coffee, and use an espresso machine, a french press, or a chemex drip. Do not trust Illy machines.

    Good coffee, like all good food will take time. If you want instant coffee, or instant food, you just want the effects, not the quality. In that case, by all means, drink meal shakes and no-doz. Leave coffee out of the equation.

  24. When I think back over the years and try to remember the best cups of coffee I ever had, it wasn’t so much about the coffee as it was about the mood/state I was in or the people I was with; I vividly remember having instant coffee with brown sugar (?!) in it on a foggy mountain top in the middle of a 100-mile backpacking trip, and it was delicious, so “good” coffee is pretty relative to me.

  25. I asked Kyle Glanville, US Barista Champion about what makes good espresso. He said tamping is not important. Anything between 20 and 80 pounds is fine.

    Using great coffee, properly roasted and freshly (like just a few seconds ago) is essential, of course.

    What surprised me is that he said precise water temperature is *extremely* important. I have a Rancilio Sylvia espresso machine. It has a lot of good things going for it, but the stock bimetallic thermostat provides lousy temperature control. It can swing as much as 40 degrees. You can narrow that range a lot by temperature surfing (google it). Better yet, get a PID temperature control kit and install it on your machine. I did and it changed everything.

  26. #29 – Yes, but one can easily ruin the best beans by

    – grinding them at the store and leaving them around for hours (or days)

    – keeping them one’s freezer

    – using water that’s too hot

    – or too cold

    – or using dirty gear

    -etc, etc.

    Of course meeting all of the above conditions will get you nowhere if your beans are no good! And don’t get me started on espresso…

    Thanks Cory “tasty scalp” Doctorow for the link. How’s your we’un?


  27. I use instant espresso… go on, flame me…

    but I do take the trouble to hand roast my green beans for preparing my push-down cafetierre coffee with and also use a little Bialetta stovetop moka express pot when I’ve time to spare like at weekends…

  28. As an intermediate coffee addict and total spacebar noob, I have learned a lot from this post and its comments. Better coffee and faster web browsing will make me a better generic humanoid carbon unit. Thanks for the upgrade.

  29. I don’t drink coffee, I think it’s nasty, bitter, acidic stuff, and I much prefer tea. That does NOT mean I don’t find articles like this fascinating, however. It brings together tech, DIY, chemistry, physics, and more. PLEASE continue to post things you find interesting. If I really don’t want to see it, I can skip it. Thanks! PS: From everything I’ve read about coffee-making, I’ve condensed true helpful advice down to “Use fresh ingredients and clean equipment.”

  30. I’ve got a drip machine for the mass quantities, and an ibrik for my turkish coffee fix. One of my favorite additions to Turkish Coffee is just a bit of cardamom.

    I’ve been thinking long and hard about making my own vacuum balance, since a new one will set me back $400 or so.

  31. When they can get BoingBoing to have interactive, personally tailored posts for each reader (based on IP address?) that will be sweet. No more being forced to read about things one despises.
    I like coffee, btw. Keep it comin’.

  32. I believe the tamp is important. My machine has excellent temperature control, and my grinder is pretty consistent. Yet some shots are godly, and others mediocre. Tamp is really the only variable left.

    P.S. I hope that isn’t – gasp – preground coffee I see in the jars on the left in the photo?

  33. @24, I’d recommend a hand-crank Zassenhaus grinder for grinding beans on the quiet (I’d actually recommend it for any grinding, but the lack of a motor makes them especially useful for quiet hours). You’d think (I thought, until I had one) that grinding the beans by hand would be tiresome… Indeed I’m sure it would be if you wanted to grind a month’s worth at a time, but doing a week’s worth takes little time and isn’t too draining on the body… Or, just add it to your ritual, grinding up the beans for that cup just before preparing it. The Zassenhaus grinders are well constructed, and adjustable over a wide variety of grinds… and you can take them camping!

  34. So I had a listen to the MP3 file, I’ve got nits to pick:

    Firstly: It’s not steam that’s going through the coffee grounds! It’s hot water. Dr. Mark Miodownik (engineer?!) contradicts himself in the piece that he recorded: At 25:10, he said that the ideal brewing temperature is between 86degC and 90degC.

    At one atmosphere, that’s liquid water. At 9 atmospheres, it’s even more so liquid water. According to one calculator I found on the ‘Net, the boiling point of water at 9 atmospheres is 170degC.

    Secondly: The pump in just about every espresso maker out there does NOT pump the heated (not steam!) water. It’s just too complicated and expensive to reliably pump steam or hot water under pressure. The water pump pumps cold water into the espresso maker’s boiler – the tank where the water is heated.

    The only place you should get steam is from the steam wand. It has a needle valve so you can control the amount of superheated water let out of the top of the boiler; which immediately vaporizes (because of the pressure drop, cooling the boiler’s water) and enters the wand as steam. (At 170degC, in case you weren’t paying attention earlier.)

    As an aside, when you tire or break your espresso maker, ask me for a recommendation:
    Most of the machines on the market use teeny, tiny little boilers. These, when set to ‘Steam’, only produce enough reserve heat (in the form of superheated water under pressure) to boil Tinker Bell-sized cups of cappucino. Good home espresso machines, like mine, have larger boilers (plus some other good engineering) so they can actually bring a half-litre of just-out-of-the-fridge cold milk to low-pitch-gurgling big-bubbles-boiling milk in one go – so you can make a good café au lait in the morning without stressing yourself out and start to work on that pesky cryptic crossword.

    Thirdly: Does the good doctor keep saying “eXpresso”? It’s eSSSpresso. Does he not have any Italian friends who’d keep correcting him till he got it right?

    Fourthly: the foam you see on the seaside is usually from milt. Y’know: sperm! “Chemicals”, yes, but really it’s from ‘bodily fluids’.
    (Good, that should free up some room on the beaches around here…)

    Next up on the rant:
    Kill-o-meters, not key-law-muters!

  35. Mark Frauenfelder: “…bout what makes good espresso…” — “Using great coffee, properly roasted and freshly (like just a few seconds ago) is essential, of course.”

    No, no, no. Great coffee yes. But you do not want to use freshly roasted coffee for espresso. Leave them in a one-way-valve bag (only lets gas out, nothing in), for three to four days, then transfer to airtight jar (mason is good). Depending on the bean, the roast and your taste leave them in the glass for three to fourteen (!!) days (once in a while let a little air out of the jar).

    I typically let my beans rest for a week before I use them. I have a particular blend that is just stellar at 10+ days.

    A former world barista champion (from Denmark, naturally) has a blend that tops in 17 days!

    Bottom line: For espresso, let the beans de-gas and develop before using them. Also if you DO use them fresh roasted, most blends will produce a completely insane amount of crema. You don’t want that.

    Oddly enough, for drip/plunger/aeropress the resting period doesn’t really matter tastewise (although fresh coffee will bloom like hell).

  36. Nerd alert:

    I think that the foam you get on espresso made from day-or-two-since-roasted beans is more from the excessive CO2 off-gassing from the beans. Crema per-se is the emulsified coffee oils coating the surface of your brew. And if it’s nice and fine, dark and thick, it’s a pretty good sign that you’re getting something right…

    see you at the (9) bar.

  37. By allergic, I mean that I get what is roughly equivalent to a case of food poisoning. without getting too graphic let’s just say there’s stuff coming out both ends. I get this to a lesser degree if I accidentally get a little coffee ice cream too, so it’s more of a drag than you might think, especially due to my love of caffeine.

    In defense of my argument, using Google to search boingboing archives, I come up with an astounding 4,040 mentions, or just over 9 a week. so even if we eliminate 8 of those due to comments or passing references, that’s still one a week, or 442 articles about coffee.

  38. Also, I realize I may have come off a bit badly in my first post, but let me say my mood about coffee may have in part been caused by having said allergic reaction to it last week.

    Also I forgot to include that while I have researched a test for coffee allergies, the only real method is to go to a doctors office with a cup of the stuff, drink, and wait for a reaction.

  39. Ordodk@43: Thanks for the info, and congrats on winnning the Denmark Championhip! I agree with you, I left the word “ground” out by mistake. The coffee should be ground just seconds before you use it, right?

  40. #37 – adding cardamom to Turkish coffee –

    I like to make Turkish coffee too, it’s relatively simple enough. Occasionally I will put 1/4 tsp of ground cloves in with it. I can’t remember what that makes it – Ethiopian or something like that. Anyway, with lots of sugar too.

    It numbs your tongue, and has this incredible aroma.

    I suppose after the first taste, you don’t taste anything, but the aftertaste lingers, and it’s not a bad one.

    Sorry about the tone of my previous post. I like coffee too, I just don’t have the time or energy to devote that much time to it. I don’t drink either, so at some point when my life calms down from kids, school, life, etc. I will probably join the coffee aficionado club. But it will have to be decaf. More than one or two cups and I turn into a different person.

Comments are closed.