บทถอดความฉบับเต็มของ Techstuff Classic: How Coffee Machines Work

recommendation for maybe not eating a whole lot of coffee cherries. Coffee cherries, by the way, are how coffee grows because it doesn't just grow in a little pre roasted bean on a bush. That's ridiculous. It's not a it's not in a pod. Now, it's not like like beans like green beans. It's not like that right right there. Their seeds really, and so they grow in what's called coffee cherries or coffee berries sometimes, which looks a little bit like a like a cherry or a grape. Like it's sort of olive size. Yeah, rap out that size, maybe a little for the smaller olives. Not not like those ginormous olives. Nonster olives. You defy the laws of man. Uh, these are these They do look kind of like grapes, kind of like like like a grape, and the cherry really got friendly and had little babies and the skin is kind of tough, but then once you pierce the skin, it's all like juicy and birsty. The skin is also very bitter, so I don't recommend chewing on the skins so much. Um. And the fruit is very sweet, it's very sticky. It's gonna subtle flavor to it. I think of it kind of like rose water and watermelon. Yeah, I think I want to eat that. Actually, that's got to be careful though, because those coffee beans, the seeds are really super hard and if you're just crunching, you could crack a tooth. Yeah, we recommend. I do know that in some places they save, They save the fruit once they've used the rest of the of the bean for coffee purposes, dry it out and use it for tea. Oh interesting, so you can brew a tea using that. Now, once you strip that fruit away, you still have some layers on top of the bean itself, right, so skins kind of. Yeah. So you have to actually go through a process to get to the point where you can get to the beans. So you harvest the coffee. So you pick these cherries. Those are either dried in the sun over the course of a week to ten days something like that, or they're placed in a pulping machine to remove the fruit and then uh, those beans are dried by the sun. Usually you can do it in other ways, but the sun is right there. Yeah, the ones I've seen that they put them in like these big uh sieves almost, and then they rake them occasionally to make sure that they're all drying evenly. Yeah, sort of like a like if you've ever been gold panning, sort of like a very large gold panning thing, right, and hey, this stuff it's it's like just as valuable as gold in my eyes, so other black gold. Yeah, after you dry it, that's when you can get those other elder layers of the being removed in a process that's called hulling, as in removing the holes around the beans. They are graded and sorted by size and density, and then the this coffee, which is referred to as green coffee, the beans have a kind of greenish tinged them, then is shipped to roasters. So you often don't have a coffee plantation and roaster on the same premises you would. You would some of the coffee plantations sell their own coffee, but it's a kind of interesting thing because they'll send the green coffee off to roasters. Roasters will send the roasted coffee back to the plantation, and then the plantation can sell it well. The roasting is a very specific process and different people have very specific ideas about exactly how much a coffee bean should be roasted, and depending on the type of coffee plant and there are like six thousand species within the coffee a genius, so you've got a lot of options in there. Yeah, it's it gets very particular. So how does how does the roasting process go? All? Right? So you get like a a roaster that can rotate, so it's got a tumbling kind of kind of like a clothes dryer. It tumbles because you want all the beans to uh, to roast evenly. You don't want to end up with like a bottom layer that is roasted to one degree and the stuff above it is to a different one than you have. You don't have consistent coffee, right right. Yeah. My first thought that I was like, it's like a rotisserie. And then I was like, but that would be terrible for beans, because you know, you can't like spit them like you can't chicken. And then he said and then he said, like a clothes dryer, and then I just thought of like a clothes dryer foot full of chickens. And then I was like, this is a terrible I'm just oh, I just need to share this with someone to get this idea out of my head. It's like the ring sounds like a rejected Gary Larson far side cartoon, Like, you know, this is too horrifying even for me. Close dryer full of chickens, well at any rate. So the roosters, they are put to a temperature of around five degrees fahrenheit, which is about eight celsius to get the beans to the right temperature and Once the beans are hot enough, they undergo a process called pyrolysis. They expand kind of like popcorn. They actually pop out and get much larger than they normally are. And the longer you roast the coffee bean, the more intense the flavors become, the more intensive aroma becomes, those oils become really concentrated. You do. However, if you're the longer you roast them, you also lose more and more of the caffeine that's inside them. So so darker beans are actually less caffeinated by the lighter flavored greener beans. Yeah, so if you have a light roast coffee, you typically have more caffeine in it than a dark roast. Keep in mind that it also depends upon the species of the coffee planet, right, Some have more caffeine than others, and depending upon the process that they're using, sometimes coffee makers will actually add caffeine back into the mix afterward, because you want to make sure that you have that kick. But yeah, some people prefer the the robust flavors of a dark coffee. They do have stronger flavors. Some people prefer the lighter flavors and the caffeine kick from the lighter coffee. Uh, and in general, lighter coffees have more caffeine. And we've been doing this or a while as human beings have been harvesting coffee for quite some times. Yes, not just Jonathan and I. We've been spending

literally hours harvesting coffee today in preparation for this podcast. By harvesting coffee, we mean breating articles and drinking it. Yeah. Legends placed the discovery of coffee a couple of thousand years ago. Um. Supposedly when a goat hurd in what would become Ethiopia noticed that his herd got real perky when they ate the berries off of this one particular plant. The goats seemed to dance, dancing, dancing the name of a of a brand of coffee. Yeah, local, local roaster and seller here in Atlanta, right. Actually, they're they're very local. They're right there. They're a ten minute walk from our office. Good good coffee if you ever get into Atlanta. Like, um, people have probably been eating coffee for a long time. East African tribes used to make uh, these balls of like animal fat plus coffee berries. Um. So if you thought that putting butter in your coffee was a whole new fangled thing. Then you're you're actually late to the game. Historians think it was developed into a drink somewhere around one thousand CE on the Arabian Peninsula, and it became hugely popular with Muslim populations there. They do not consume alcohol, so I assumed that this was a thing that they were kind of like, yeah, drugs are good. Um, yeah, this is an alcohol, and yet it gives us an interesting energetic feeling. Um. And it spread as the religion spread throughout the next few centuries. Legend also has it that coffee growers were so protective of their crops that they didn't allow plants or even fertile seeds to leave the Arabian Peninsula for for hundreds of years until a man smuggled some seeds out of Mecca by strapping them to his chest. Interesting um, whether or not that is true. India definitely had some coffee crops growing by about sixteen hundred, and European travelers around that time started catching on to this whole coffee thing. The Dutch were the first to the first Europeans to start up a coffee estate that was on Java, Java Island in sixteen sixteen, and we think it arrived over in the America's, possibly also through smuggling. Around the seventeen twenties. Brazil and Columbia are now the largest producers of coffee, followed up by Indonesia and Vietnam. I remember hearing a story at one point about uh that smuggling of of coffee beans into the America's through uh being hidden in flowers. Yeah, yeah, I heard that. Um Uh Brazilian foreign dignitary uh talked real pretty too to the wife of someone over in a coffee growing estate and then to smuggle them back to back to Brazil where it flourished. But so smuggling big in the coffee world, as it turns out, like one of those things where this belongs to the world for freedom, for free. Up, We're gonna take a quick coffee break from this episode to grab ourselves a cup of Joe. Suggest you do the same, and we'll be right back. So let's talk about the history of the action of the coffee machines, the various devices we have used to make coffee. Some of these, you know, you might argue, UH take the term machine pretty liberally, but it is interesting to note that even the most simplistic methods of making coffee have a relation to the standard coffee drip machine that a lot of people have in their homes. Oh yeah, yeah, these first two are not electronic forms, but I would remind you that even a lever is a machine. That's true, although the first one I hesitate to call a machine. It's really more like a device or a prop Um. The simplest way to make coffee or yeah, it's just by pouring hot water over or through some grounds. Um, I'm very fond of my drip cone personally. It's just a cone shaped thing and you put a filter in it to contain the grounds, and you place the whole contraption on top of a coffee cup and then you pour hot water through it until the cup is full of coffee, and then yeah, everything is better in the universe. Um. A little bit more complicated than that is what's known in the US as a French press and more generally around the world as a coffee press or coffee plunger or cavitieri, a piston. And this is a very simple manual machine, uh, manpowered or woman powered, person powered really, um, consisting of you know, cylindrical chamber and a fitted filter that's attached to a rod. You steep the coffee grounds in hot water in the chamber, and when it's brewed to your liking, you just push the filtered down own into the chamber. That the water flows up through the filter and it collects the grounds at the bottom of the chamber. Which let's see, pour non chewy coffee off of the top and you, uh, you gotta make that. You've got to make both the pressing uh very smooth and slow and the pouring you need to make nice and smooth and slow so that you make sure you're not stirring up a lot of sediment. You can get sediment from French press. Coffee definitely usually tends to end up in the cup no matter what. The first time I ever used a French press was at a restaurant in Las Vegas with lots of people all around me, and I just felt like, I've got to do this right or everyone will judge me. And I know that what happens in Vegas stays in Vegas, but I'm not even comfortable with that. To tell you the truth, I want to make sure and um, yeah, so you are just pushing the grounds further and further down to the bottom, while the water is allowed to go through the filter or the brood. Coffee at that point's night and water. It's brewed coffee is able to pass through the filter so that you can pour it into your cup. And a lot of people like this method because they think it brews a particularly smooth cup of coffee. Yeah, and unlike unlike coffee that eases paper filters and it's processing even like with my drip cone. Uh, you're allowing all of the oils and the coffee to make their way into your cup. Oil is kind of where the flavor is residing. So if the paper is absorbing some of the oil, you're losing a little bit of something and getting a tiny little bit of paper fiber in there. And and some people are just like, that's just not

acceptable, unacceptable, purest form of coffee oil to go into my system as possible. I do. I do prefer French press to all other forms of coffee. That might be a coffee snob. The idea of fixing a screen like straight to a pot in order to avoid getting grounds in your cup probably goes back aways. But the first patent on the on. The actual plunger device was granted in France in nineteen nine, hence the term French press. Now, if we go back further to the early eighteen hundreds, that's when we get the first inventions of the percolators. Now we may be familiar with a percolator that if you've ever seen a coffee pot's got a little like knob type protrusion on the very top that's clear. Yeah, it looks sort of like a sort of like do you remember the board games, sorry, from when you were a kid that popmatic bubble? Yeah, yeah, I always when I was a kid, I thought that my grandmother's percolator coffee cup would probably had a popomatic bubble and she was like, don't touch that, it's hot. Yeah yeah, And in fact it would be hot. And the reason why it's clear is so that you can see when the coffee has been has finished percolating, in case you could not hear it finishing. So this is a really simple machine as well. You've got a chamber at the bottom of the pot. This is the one that's you know, closest to the source of heat. This is where the water goes, and a tube leeds up from this chamber to the top of the pot. You put the right amount of water in and coffee grounds go into another chamber. That's it's at the very top of the pot. So you've got a filter at the base of the coffee grounds chamber. So here's the deal. You've got the whole coffee pot on a heat source. The heat source heats the water to boiling. That boiling water starts to push water up the tube. It forces water up that tube because there's nowhere else for it to go. So the water goes up the tube where it bubbles over the top. That's where you see on the top of the percolator a little water bubbling over. When it bubbles over the top, it goes down into the coffee grounds, and so the coffee grounds and the water get having a little party up there. It absorbs some of those coffee oils. Uh the now coffee or very weakly brewed coffee at this point starts to seep down, eventually going down through the filter and back into the chamber below. It continues this process as the cooler water is sinking closer to the heat source, getting a heated up boiling going up through that tube. The process continues in a cycle until you're getting to a point where all the water inside the percolator is near boiling temperature. Now you don't want it to actually boil boil, because they say that boiled coffee is spoiled coffee's not gonna taste good. But you want, like like any other food, you can totally burn coffee. Oh yeah, and you know it when you've had it, you're just like, it's a flavor of failure. It is, it is, and it's you know, you're like, I'm still gonna drink it, but I'm not happy. So this this continues until that percolating sound stops. That's a signal that the water has reached this temperature of near boiling, and you remove it from the heat, and then you're able to remove the grounds and pour cups of coffee and uh and a lot of people really still prefer percolator coffee, whether it's one some percolators have a heating element actually in the coffee thing, so you just plug it in and an electric kettle, yeah, and then others are meant to go directly onto a heating element, whether it's an electric stove, gas, though maybe even a fire if you're a cowboy, because is that the cowboys made coffee? Or a camper yeah, or a camper um um, So that again popular but very simple yeahs. And but actually, well, I mean most most coffeemakers are very simple. I hadn't thought about it very much until we started doing this research. And the next one is a vacuum drip, yeah, which looks like it's something super cool and hip history and chemistry related. Oh yeah, yeah. When the first time that I saw one was in a relatively fancy restaurant down in St. Petersburg, I believe, actually and Florida or Russia, Florida, just just checking and and and it looked it looked like this crazy like like fifties era space age kind of thing, or possibly like something from like from like gas Light sci fi kind of which which is true because that's about when it dates from it even it dates before flight sci Fi because it comes from the eighteen thirties. But it's one of those that we've seen a resurgence in recently as people have you know, gone on the quest for the perfect cup of coffee. And this is another one that is based on a very similar principle as to the percolator uh in several ways. So if you looked at one of these, they tend to look something like kind of like an hourglass shape. The bottom chamber is one that holds the water. It's connected via a tube that has a filter in it to an upper chamber. The upper chamber is open to the atmosphere. Is not closed, Yeah, exactly, it's not. It's not sealed like an hour glasses. You put the coffee grounds in that. Now the filter keeps the coffee grounds from going down into the lower chamber. UH. And you would then turn on the heat allow the water in the bottom chamber to start to boil. That would make water vapor that would force it creates an increase of water and air pressure weather because the water vapors taking up more space than the water was. That's forcing water up that tube through the filter to mingle with the coffee grounds. With these vacuum drip sets, you are supposed to stir the coffee grounds and water together a little bit so that you get a good amount of coverage and you get the coffee grounds sufficiently wet so that those oils seep into the water when it cools down, the water vapor in the bottom chamber begins to condense. That creates a vacuum which starts to pull the coffee back down the tube through the filter so you don't get any grounds, and it fills up that lower chamber not with water but

now with brood coffee. So that's why it's called a vacuum drip. It's because that water vapor wentzn condensing creates the vacuum pulling the coffee back down. It looks like magic. It looks like fancy coffee science magic while that's going on, and it definitely looks like you know, you're like I have had a mad scientist brew me a cup of coffee, and uh, it's very pretty. Like a lot of these are very very The design just makes it look really appealing. There's a very strong aesthetic appeal to these, certainly more than you know, an average coffee maker. Right, A lot of those coffee makers are very functional. They're not necessarily pretty. You can come pretty ones, but right, right, but most of them are pretty uh utilitarian, not pretty pretty, not pretty. Mine mine looks fine, but it doesn't look space age. Um mine actually has a coffee grinder permanent filter and uh and you know, all that kind of stuff mixed into to it, so it grinds my coffee just as I need it brewed, which is nice, yes, yes, also very important to fear a coffee snob. Yeah, so that you have less surface area to get stale while you're you know exactly, yeah, so as you get that that really fresh taste. The next one we want to talk about is the mocha pot, which is going to sound very similar to the other ones we've just mentioned, but moca pot coffees sort of the kind of coffee brew with. This exists in a weird world between the espresso and the coffee. So espresso will talk about later, but it has its own particular uh traits, whereas they're that are slightly different from from coffee, and this is kind of bringing the gap. And it's very popular in Europe, particularly in countries like Italy and France. My my my roommate has one of these that has passed down to her from her Italian grandmother's makes perfect sense, and these are really cool for like portable coffee makers, they're very they tend to be very compact, and they work on any heating surface. You can for camping or cowboying, whatever you're doing, you can just kind of bring it with you exactly. And it's very similar again to the percolators. The vacuum drips has a similar principle. So you've got again two chambers, the lower chambers where the water goes uh, and then there's kind of it looks almost like a funnel. There's a coffee grounds cone that fits into the lower chamber. All right, So you've fill the lower chamber with water up to the right level, which would be below where the cone uh stops where the coffee grounds would start. Because you don't want to have the water so high that the coffee grounds are already getting wet. Uh. There is a tube that leads down into the chamber from the coffee grounds cone. There's a filter there so the coffee grounds don't again go into the lower chamber. And then there's another tube that leads up from the base of the kettle part like the pot part, the part that will hold the coffee uh, and they screw together you put them on this heating element. The heating element heats

the water to boiling. Water is forced up through the tube of the coffee grounds cone. It then ends up mingling with the coffee grounds, thus creating brood coffee. Uh. It continues to do so because you keep the heat on, the water just continues to flow up through this tube into the coffee grounds. So the water in the coffee grounds level can't go down because the the expanding water vapor from below is preventing it. You can only go up. So it goes up through another filter and up through it the tube in the center of the pot and spills over that, and that's where it ends up forming the coffee inside the pot section. And again you have to pay a really close attention to this because if you let it go on too long, then it's just gonna start sputtering because all that's happening is water vapor is being forced up through the tube. There's no more there's not enough water for it to be an actual stream. You remove it from the heat. You then can pour out either you can pour out extremely concentrated cups of coffee. It's really more like espresso. At that point, you would you would generally either dilute it with hot water or hot milk of some kind. Yeah, exactly that that tends to be the way to drink it. You can also drink it in the very tiny cups, kind of similar to espresso. I've seen that happen too, but yeah, no, I prefer to do it that way because then you get superpower. Yeah. My superpower is that I can no longer detect individual heart rate. And you want like I can't is there's no more thumping. It's just a thrumb. Oh oh, I love it. I love it when you could just feel every single blood cell in your body is moves through your veins. It's beautiful, start to name them. Uh yeah, in that case, I I go beyond space and time and I like to try and keep my feet on the ground, so I don't I dilute it if I drink it this style. Um, but it is is a very common way of making coffee in different areas of Europe, and I guess there are a few folks in America who make it that way too, although we tend in America to to depend upon the automatic drip coffee machine. And this is the machine that people wanted to know, how the heck does that work? Yes, these electric devices that you buy for for very low amounts of money, really and you just plug it in, and it makes everything okay. It's kind of interesting because it's very similar to the principles we've already covered. In fact, I was surprised, you know, before I thought about this. I suppose if I had left, you know, really critically thought about it, it it would have occurred to me. But I had just assumed there was some sort of water pump somewhere in the typical coffee machine. But that's not the case, all right. It's all using the same kind of air pressure and physics that these previous simpler versions, non electronic versions have been using exactly. So really the electronic part in this case is the heating element that's contained within the coffee maker. That's really the big UH invention is that the heating element is not an external one. It's part of the machine. So your basic element. Basically parts of a coffee machine include the reservoir that's where you pour the water into. The reservoir has a drain at the base of it. UH. That drain has a one way water valve which allows water to pass through the drain but not come back up, which will be important in a moment. Yes, Then you have a tube that connects that hole that that reservoir that's connected to the valve on one side and to essentially a shower head it's what they tend to call it on the other side, because because it's sort of like a sprinkler, it's a eventually going to drip water out over your coffee right grounds exactly. So this tube is made usually of an aluminium because aluminum is very very good at conducting heat, very good thermal conductor. And you want that good and yes you do. And so, uh, the tube is where that that water just will pass straight through the still water at this point it hasn't touched coffee grounds yet. And then you have the heating element, and the heating element uses resistive heating to elevate the water's temperature rapidly. And we've talked about resistive heating and previous episodes of text stuff. Sure, but for a quick reminder, Yeah, so when you have electricity passing through a conductive material, you lose some of that energy, some of that electricity. You don't get a one to one. So let's say you have a one hundred electricity units. I'm making this super simple one electricity units that are going in from one side and then you've got a little detector at the other side, and you see that there are only eighty electricity units coming out the other side, and you realize that the other twenty electricity units have been lost in the form of heat. The actual conductor's temperature has increased. So that is incredibly simple, I realized. But just to illustrate the point, that's the basis behind resistive heating, as is the way electrical heating components work. Electricity passes through the conductive material, it heats up the conductive material, and usually that's waste, but you can make it work for you. UM resistance is dependent upon a couple of things. The material itself, so like you know whether it's copper or whatever, whatever conductive material you're using, and it's also dependent upon how much of that material you have, how big a diameter of wire you have gauge of that wire. In other words, UM and the thicker the wire, the lower the resistance. So using that logic, if you use a very thin wire of a conductive material and you make a really tight coil of it and it's long, then you've got a lot of surface area there. You can create a lot of heat. The resistance of that wire is very high, so in a relatively small element. And if you were to do that and then put that so that the the aluminium tube which typically has at least one bend in it inside your coffee maker to to give you more surface area. Yeah, you want you want that

pathway the water goes through to be long enough so that you can heat it has a chance to heat adequately. So you you you have this kind of lining the tube. And now we get to what happens when you actually uh put water into the reservoir. So here's how the coffee making process happens. In one of these automatic drips, you pour the water into the reservoir. That water starts to move through that one way valve into the tube, fills up the tube. You turn on the switch and we turn the switch. The heating element is provided electrical current and it gets hot, so the tube starts to heat up. That heats up the water inside of it. There are no other moving parts here. All that's happening is the water gets heated to the point where it's boiling, and that boiling does the same thing it did in those other implementations we talked about with making coffee. It starts to push the water up the tube. It can't go back the way it came because that one way valve blocks the way right, So it's sorry, guys, can't go this way, you gotta go the other way. So yeah, so the steam pushes it into that little shower head thing down onto your coffee where it drips through the coffee grounds and into a waiting craft. Yep, so you've got the the filter that obviously keeps the coffee grounds from ing into the craft because no one wants that. Hopefully. I've had a few disastrous where you've you've forgotten to put in a filter or yeah, the one I have. Mine has a gold mesh filter, so you have to wash the filter after ever you use. Yeah, but but you don't have to buy filters, which is nice. Um, But anyway, you uh that that's where you get the coffee. The coffee ends up the brood. Coffee is up in the craft. Now you're not able to control how long the water stays with the coffee grounds, how much of the coffee grounds are actually covered in water, because I mean, it's just it's just being dripped on. So there are some limitations, certainly, and different machines control that for you to certain extents, but but most of them are pretty basic. Yeah. Yeah, so the bright side is no moving parts, so it's really pretty a simple machine. If your coffee maker has broken, it's because the heating element isn't working, that's the most or that the one way valve is clogged up. Right. Yeah, if if your coffee machine does stop functioning, first of all, I'm sorry, Yeah, I know, we're here for you. We we feel your pain. In fact, our coffee machine this morning at work, which is not an automatic drip coffee machine, was not working and it was a crisis, people, which was only solved by an epic journey to Dancing Goods coffee shop that's about a about a five minute walk away. Yeah uh but yeah, if if this happens to your coffee machine, UM, and it is an automatic drip, you can you can first check the one way valve to see if it's either stuck or clogged. Usually just like poking a toothpick or something like that in there. We'll we'll help you see what's going on. Um. Or you can try running vinegar through the machine to clean out any calcium deposits that might have accumulated in the tubes because electricity plus aluminum plus water plus yeah, calcium happens. So afterwards, just run two batches of water through the machine to rinse out all the rest of the vinegar. Because you do not want vinegary coffee, or maybe you do, but if you do, you know, more power to you. But I will decline cup from you because I got enough frustration in my life. Okay, I'm so canfidated right now. This is Jonathan from the future. We're gonna take another quick break so I can kind of calm down and we'll finish this episode about coffee machines. Okay, all right, just one more espresso. So let's look at some of the special coffee makers that are out there, because there are a few, and I thought it would be kind of interesting to look at how some of them are different, Like the Clover coffee machine. This is one. Clover was a company that was purchased by another little company called Starbucks. So some Starbucks UH locations have Clover coffee machines and you can get a Clover brewed cup of coffee that's different from their normal cups of coff How how is it different? Jonathan tastes better in my opinion, I've had a Clover cup of coffee. There's actually actually the Starbucks across the street from our office has one. That's one of the locations that has one, So if you ever go across the street, then you can get one of these. Um, it takes a little longer to brew, but it's kind of worth it. I think I've been completely ignorant of clever coffee machines until we did this podcast, and we have an article on it at Health which I didn't even know. I was just I was doing a search on how stuff works for coffee, just to see what all the different links we had, and when this one popped up, like, really, we've got one on clover coffee, okay, and I read it, Oh, this is kind of interesting. So it's it does have some different elements to it than your average automatic drip coffee machines do, and in fact, it has a lot in common with the French press method. So first off, it has and I love this term a quote proportional integral derivative controller into quote, which is a fancy way of saying it's got a system to really monitor the temperature of the water and make sure the temperature you want. You can actually in some of these sets the specific temperatures. So if it tells you that your coffee beans should be brewed at a specific temperature, you can set that and it will keep the water as close to that temperature as possible. That's that's pretty awesome. Yeah, that's pretty exciting. Then it also has a way of letting you determine how long the water and coffee grounds can party time excellent together because you want to make sure you have a nice thoroughly brewed cup of coffee, not overbrewed, but not underbrewed. So you want to get the ideal amount of those those coffee oils in the water. And also it has a brewing chamber where you're supposed to stir it because

because coffee needs love, so you stir the coffee grounds a little bit in the water. Once the water go once the water is heated up and goes into the brewing chamber, that's when you give it a little bit of stir to make sure it's it's properly mixed. Once it's done, then, uh, there's a piston inside that brewing chamber, and the pistons usual resting position is at the bottom of the chamber. The coffee grounds are on top of it. Water comes in it, commingles uh. The bottom of the piston has a mesh kind of filter. So then when you are done brewing the coffee, the piston rises up through the brewing chamber, lifting up all the coffee grounds, leaving the brewed coffee behind until it reaches the very top, and then you see this little cake of coffee grounds come out of the hole. But it's not done yet. The drain opens and it creates a vacuum and the piston goes down being pulled by that vacuum. The coffee drains out and then is dispensed into your cup. At the very end, the piston comes back to the top so that you can get a little it looks like a little like window scraper, and you pull the grounds across, and there's in the clover machines, there's a a little hole where the waste coffee grounds go, so you just pull them over into the waste basket essentially, and then it's ready for its next cup and you can drink your delicious cup of clear coffee. So that's that's your clover. But we have other ones we want to talk about. We've been talking about coffee, but what about what about this here espresso? I just got a shiver right in the right in the base of my neck. Okay, espresso, Espresso? U is it is not a different kind of of bean. Well, I mean, I mean specific kinds of coffee. Beans are generally considered best use for espresso. They're roasted longer than beans for coffee, and they are ground very very very very fine, more more like powdered sugar than than coffee grounds. Right, So you do not ever want to put like if you had ground espresso, you would not want to put in a coffee maker. No, that would probably reek havoc on the fine little machine parts. It's just gonna it's just gonna go right through the filter. I'm gonna end up with a cloudy, nasty cup of grossness. Yes, And an espresso actually refers to a pressing um. It's it's from the Italian word for for press, and it's so it's made by by packing these very fine grounds very tightly and forcing a small amount of water through them, just one point five ounces if you're being traditional about it, and most people are so we're talking. That's when you see the tamping right where risks will tamp down, so it's nice and tightly packed right right, And uh, it's so densely packed in fact, that the we edges of each particle of powder start interlocking with each other, which makes it really difficult for the water to get through them. Like like to thirty seconds is the ideal amount of time for one point five ounces of water to make its way through a pole of espresso. Wow, so you're using a pressure to

push this water through, I imagine, not just gravity right, definitely, Um, an espresso machine can can actually be as simple as many of the devices we were talking about earlier. Just like a like a heatable water reservoir placed beneath a disc of grounds, again using a filter to make sure that the the grounds are stay in place and don't drip down into the water. Um. And then a single way for the water to get out of this heating system, which is a pipe at the top of the grounds container. When you boil the water in the reservoir, the heat of the system will increase the pressure. The water will be forced up through the grounds and then out through the pipe, which you'll ideally want to curve around into a little bit of a spigot, unless you want to boiling espresso fountain, which sounds festive but painful, yes, well and not quite boiling. Um, well, okay, in that case, it would be boiling. And that is why most people do not use this method, because the ideal temperature for espresso is below boiling uh somewhere around a D nine two degrees fahrenheit in fact, uh So most espresso machines use a pump in order to not overheat the water. So instead of it using the boiling method we've talked about, there's actually a pump mechanism right right. They otherwise work a whole lot like a regular coffee machine. Um. What happens here is that this this pump will draw water from the reservoir into a chamber containing a heating element, and when the water is heated to the correct temperature, the pump will pressurize the chamber to about fifteen atmospheres, which is two twenty pounds per square inch, and that will force the water down into your little packed, filter bound disc of grounds. That's the removable part from an espresso machine. Uh, a little handle on it. Yeah, and UM. Then after a few seconds, it will start being forced down out through a spout at the bottom of that disk into your you know. I actually, at one time I demonstrated a handheld espresso machine. Oh that's right, yeah, yeah. So it's a handle that looked like it had a globe at the end of it, and the globe is where you would put the the espresso grounds. You tamp it down and put them in this one section of the globe, UH had a filter built into it so it wouldn't allow espresso grounds to go through, and you would pour water into it had a heating element that would heat it up very very hot, very very quickly, and it used pressurized gas, in this case nitrous oxide nitrous ox side cancers that would plug in through the handle. You'd screw the handle in shut very important as it turns out, and you don't want to shoot a nitrous ox side canister across the building. Um. And then when you pull the trigger, it would release the nitrous ox side which would create the pressure to force the hot water through the grounds and thus brew your the amount of espresso. I discovered that if you are super sleepy at three am, because you are going to go live on television in in two hours. It is the wrong time for you to decide to unscrew the end of the handle so that you can show how easy it is to insert a nitrous ox side canst, when in fact there's not a fully depleted nitros ox side caster already in the device. I dosed myself with laughing gas completely by accident, nearly froze my face off in the process, three in the morning, and meanwhile there's a little little canstor nitrous ox side spinning in the corner of the room. My dogs are wondering what happened. That was a memorable morning for me. Uh. Now we also have there's also other things we could talk about. We could talk about Curig style pod coffee makers. We didn't really go into detail on that. It's using, uh kind of just the hot water through concentrated coffee method. Sure, I actually do think that could probably make its own episode, especially with all of the copyright issues that are going on right now. Yeah, that would probably be It really is its own episode. So we're not going to cover it now because frankly, it's just too much. But I love that you have the question in our notes, and I decided to go ahead and answer it about what are coffee crystals? Yeah? What's up with those? Like Folger's instant coffee? Right? Right? Are those little um packets that Starbucks sells? Yeah? The via via? Yeah? I think you're right. I never know how you're supposed to pronounce the Italian words that Starbucks has copyrighted. Sometimes, why are all of your why are all the names of your of your sizes? Why do they all mean big um at any rate? Instant coffee? So this is coffee concentrate. Really, it's coffee that was already brewed once and then essentially dehydrated through freeze drying. Dehydrated coffee. Yeah, you hydrated liquid? What? Yeah? So you brew the coffee, right you? You brew it super concentrated coffee like way stronger than any human being would ever want to drink. Okay, so not like not like the coffee that I like to drink, like Kish coffee. More than that. You don't want to drink it that way, trust me, it would. It would turn your eyes inside out. You don't want it. Uh So when it's rehydrated, it has it becomes a beverage resembling coffee. Yeah, if you believe the folders commercials, it's indistinguishable from a fine cup of coffee. And and perhaps that's true, I have become a coffee snob. It was invented in e nine in New Zealand. So the dehydration process is freeze drying. The fundamental principle here is called sublimation, which is the shift from a solid to a gas, skipping the liquid stage. So if you're going from solid to gas, you're already thinking how is concentrate coffee either of these things? And the reason first, you got to freeze it. You freeze it very very quickly. Uh. If you don't freeze it very quickly, then the process does not work very well. And the frozen granules of coffee are placed on a flat drying surface, which then goes into a vacuum chamber. The vacuum chamber is warmed and the water within those granules, the frozen water expands quickly into

gas like like, it skips the liquid base because the vacuum creates a difference in pressure. So so it goes straight from from frozen to oh I'm everywhere water vapor. Yeah. And so then you have condensers that remove the water from the chamber, and all that's left is this concentrated coffee granule, and that is what ends up being the concentrate coffee that you can add to hot water and thus turn into instant coffee. So you can also turn it into a pretty good stage blood. Oh yeah, yeah, yeah, it's an excellent color coloring for for fake blood if you ever need to make some that in a little bit of food dye, and depending on whether you want a very viscous blood or something a little bit more liquid, you can add some like corn starch or corn syrup or something that familiar with the corn syrup. I'm way too familiar with the corn sharp, but yeah, it adds that kind of like good rust color that the blood needs so that you don't have the handy red right right, right right, yeah, So you get the more of the rob zombie style and less of the nineteen seventies Italian horror style. Gotcha. Well, one other thing I wanted to mention was an interesting use for coffee grounds. Now, this is an idea that came out of a Green Gadget seminar in two thousand nine, So this was kind of a concept that's never been actually implemented into a product, but I always thought it was interesting, and we do have an article on this stuff works too. It's funny because it doesn't really exists beyond the idea stage as far as I can tell. But it's the really coffee printer r I t I coffee printer. Coffee printer. Yeah, it doesn't print coffee for you to drink. It uses coffee grounds. Like like, you've already brewed your coffee, so you're already happy, Lauren. It's okay, you're already in your house. Okay, okay, you've got your coffee. But now you've got these coffee grounds, right, what are you gonna do with them? Because coffee grounds are acidic, so you can't just you know, you can use them in compost, but they are acidic, yes, so you have to be careful what kind of plants you feed them too, because some plants are not gonna do well with this at ex soils um. So what do you do with your coffee grounds once you're done with them? Besides just toss them away or or maybe compost them. Well, the coffee printer may be a solution for you. You would end up using the coffee grounds. You put them into a little canister that would fit into the printer. It would actually be um still uh, external to the printer, so it's not like not like one of those things where you have to lift up a lid and get access to it. It It would actually be poking up out of the top. You add some water to it, and essentially the water and coffee grounds combine so that you get some of those oils and you're staining the paper coffee stains and it also, yeah, I've done that before, and of course I've used coffee to make kind of the antiquated looking paper. You know that. That's one of the treatments you can use very

useful parchment. Yes, if you were ever in a Renaissance festival, giant air quotes and you have to write letters to people as your character at the Renaissance festival. It's part of the rehearsal. Yeah, I had to. I can't tell you how many love and hate letters I had to write for the Georgia Renaissance Festival as part of the rehearsal process. I would always treat mine this way so that way it would look like an old letter. Presentation was important of course, of course, at any rate, So with the printer the neat design here, in order to make this really green, they wanted to not just make the ink green, not literally green, but you know, economically or environmentally conscious, right, they decided to remove the useful feature that a lot of printers have where it automatically moves the cartridge across the paper as it prints. You have to manually grab onto the cartridge and move it backwards and forwards, so it's going left and right across the page, like like a manual loom, manual shuttle for a loom, rather than I don't know how many of you actually have any idea of what a manual loom looks like. That might be a very specific reference, like this arts game loom. It's a great game at any rate. Uh So, yeah, you would manually move of this left and right across the page. Presumably there would be some sort of automatic system to feed the page through the printer, and also there would have to be some automatic ink jet system to actually have the ink print on the paper itself. So I don't know how that would have been reconciled, Like how what was the solution to that? Because obviously the speed at which I move the cartridge left and right might be different from the speed anyone else does, so you've got to figure all that into your design. But it was a really interesting concept. Again, it's not a real product you can go out and get, but you know, just like, yeah, like if if coffee stains things, why not do it on purpose and make use of it, and then you don't have to go out and buy toner. You would just use your old coffee grounds. Just kind of a neat idea. Plus, you know, if people were really interested they could They might not be complaining that they didn't get a handwritten letter because their letters smell like coffee and it's hand print it, so that actually counts for more. Like I put a lot of effort into printing this one sheet of paper. I had to move that cartridge back left and right like two thousand times. Uh So yeah, that was you know, this was a fun little topic to go into, and maybe we will revisit the sort of curis pod style coffee machines because there's a lot of controversy around that. There is there is, Yeah, I would I would love to come back and talk about that. Shout out to Paul on Twitter for suggesting me for this episode. I think I think Jonathan you were talking about like, oh, I want to maybe this coffee episode, like who could I possibly get to co host it? And Paul, who follows both of us, was like, I think Lauren talks about coffee like every day. Yeah. As it turns out, it was a perfect choice, perfect choice for co host, So Paul, thank you so much. I hope you enjoyed that classic episode how coffee machines work from back in. If you have suggestions for topics I should cover on future episodes of tech Stuff, please reach out to me. The handle we is on Twitter is tex Stuff H s W and I'll talk to you again reallyasen y. Text Stuff is an I Heart Radio production. For more podcasts from I Heart Radio, visit the I Heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.