Pour Over Geometry: Engineering Great Coffee

In this episode, I dive deep into the engineering and geometry behind pour-over coffee brewers, drawing from my background as a drainage engineer to explain how water flow impacts extraction. I break down the science behind popular brewers like the Hario V60, Fellow Stagg, Deep 27, and the UFO dripper, examining how their cone angles and design features manipulate water flow to create different extraction profiles. I demonstrate how steep angles create faster flow rates, while gentler slopes allow for longer contact time between water and coffee grounds, ultimately affecting the flavor in your cup.

Listeners will learn how to think critically about their brewing equipment by understanding the relationship between brewer geometry, grind size, and extraction percentage. I share real-world experiments, including surprising results from using extremely coarse grinds on slow-draining brewers and explain why certain devices require specific grind adjustments. Whether you're using a V60, a flat-bottom dripper, or something more exotic, you'll walk away with a framework for mastering your brewing device by understanding its fundamental design principles rather than just following recipes.

Chapters

• 0:00 Intro
• 1:45 Understanding Pour Over Design and Water Flow
• 3:35 Hario V60: Analyzing the 60-Degree Cone
• 5:10 Flat Bottom Brewers: A Different Approach
• 6:50 Deep 27: The Steepest Angle Experiment
• 8:30 Comparing Extraction Speeds Across Brewers
• 10:20 The UFO Dripper: Extreme Slow Brewing
• 12:10 Grind Size Experiments with Different Brewers
• 14:45 The Surprising Coarse Grind Results
• 16:45 Master Your Equipment: Key Takeaways

Transcript

[00:00:00]
In my former life, I was a drainage engineer. My channel was all about trying to make things better. There was some erosion, you fix it with rock, lay down the slopes and all that stuff. A lot of times whenever I would think about that type of work, I always thought about coffee.

[00:00:32]
Because coffee is one of those things where you kind of wonder how it really works. In this case, we're talking about pour overs. When we look at a pour over device in general, we see it for what it is, right? It's some type of cone shape or flat bottom dripper as we have here.

[00:01:01]
But a lot of us, or at least some of us, don't go to the extreme. I'm not that extreme. The people who actually make these devices are the ones who are the extremists of seeing what they can do to make it different, better.

[00:01:18]
I've said it before, you've heard it before. All we're really trying to do with these brewers is to manipulate flow to provide the most extraction that we can get in our cup of coffee.

[00:01:32]
So we're going to take our friend, our best friend, a friend that we've known for a very long time. We're going to play around with the Hario V60. This is our first one. I always used to get mad when people would talk about taking a cross section and look at the device for what it is. So now you have a 2D image of what it is. I never really could understand it totally, but I'm doing that to you now.

[00:02:08]
Hario V60 is a 60-degree shaped cone, right? It's not crazy steep, but it's pretty relatively steep compared to other brewers that are out there. So when you think about it, let's just take a slope. This is a better idea of what I'm trying to talk about. This is essentially the Hario V60 right there. That's the slope.

[00:03:01]
So if you were to put a pebble at the top, how fast can it really go? We're not going to be talking about the papers. That's a story for another day. Trust me, because I can get wacky too. So what would you think will happen to the pebble? It will go relatively fast. We can get the law of speed and velocity and all that to see how fast it travels.

[00:03:16]
In this case, the pebble is a water drop and it's going to pass through a bed of coffee. This is a Hario V60. We're not going to even talk about the ridges or the grooves that come up to help direct water flow.

[00:03:35]
What happens is when there's no grooves in it at all, when you put water in it, the coffee tends to stick to the sides quite a bit, a lot more compared to the regular Hario V60. Again, paper filters, that's a story for another day.

[00:04:22]
But it does it differently just because there's no pronounced grooves to help direct the water. It actually takes a very long time for the water to drain out of this particular device because of this particular design.

[00:05:26]
So the slant isn't as pronounced. I don't know what that is. It's probably like a 45-degree bend. The cool thing about this particular brewer is that it has these little channels at the bottom to direct the water after it's been transformed with the coffee downwards.

[00:05:50]
But again, the cool thing, the saving grace about flat bottom brewers is that they don't really worry so much about what's happening on the side because most of the action is happening in the middle. That's true for cone shaped drippers too. But we're not as concerned with the sides because that's not what these drippers are really mainly made for. It's a flat bottom trying to get that even extraction.

[00:06:24]
Full body to an extent, but more balanced cup compared to a cone shaped filter pour.

[00:06:35]
Now I'm going to show you two extremes. The next one is the Deep 27.

[00:06:48]
Now look at that. That is steep. That is fast just by the nature of the brewer itself, the way that it's designed. Of course the paper filter does help. It does have some grooves in here to direct the flow so we can have the least amount of channeling happening in this brewer whatsoever. But it's fast.

[00:07:39]
It works really fast just because the gravity is so steep. And it's not going to have enough contact time in order to transform and manipulate that coffee to provide the right extraction.

[00:07:54]
So those are some of the things that we have to look at when we're trying to understand our coffee. All of these brewers work. They have their own ways of creating magic for us. They all work.

[00:08:09]
They do amazing, great things for us. There's pros and cons to all of them. But at the end of the day we have to understand the geometry, what it's actually doing, if it actually makes sense for us when we're brewing our cup of coffee.

[00:09:29]
This one was the fastest one. Extraction still tasted fine and lovely. But I like a 20 percent extraction. But that means I had to go a lot finer. That's just the nature of the beast with this one and it keeps the coffee hot because of the material. Again, story for another day.

[00:10:17]
Now this one. This is called a UFO, very weird type of design to me. It looks weird. It's ceramic. It's made extremely well. But when you look at it objectively, you have the middle right here. Look at that slant. That is literally the biggest slant, the biggest angle that you have here.

[00:11:08]
You put a pebble up here and it's going to take a good time to come all the way down.

[00:11:18]
Again, the first time I used this, I used a cone shaped filter. I think if you use a cone shape because of the ridges the way it's designed, it really doesn't fit too well. I think the flow is a lot faster. However, if you use the filters that are actually made for this device, it's one of the slowest drippers that you can get.

[00:11:56]
This one is pretty close. This one's slow too. This one you can manipulate a little bit more. You're going to have a little bit finer grind with this particular brewer just because if you don't do it...

[00:12:50]
The most that you could put in it is about 30 grams and I used my EK 43 just for a test on it. It was a dark roast. So I did 30 grams.

[00:13:11]
I purposely, because I tried it before and something about this seemed kind of odd on the Fellow Ode too, I went ahead and did like a seven or eight on the grinder. I've talked about this before, my little rant is true that most of the grind settings are crap. So they have this degree of use from one to whatever it may be.

[00:13:43]
Truthfully though, for the Fellow Ode, eight all the way to one, so it goes up to 11, those other grind settings are crap. But I was pleasantly surprised how a medium roast on eight extracted. So I tried to experiment with this grinder and with this brewer on the EK 43. And if you know the EK 43, it goes from one to eleven and it's really the grinder that's as balanced as can be.

[00:14:37]
I kid you not. Usually for one point five ratio, for 1 to 15 I get an extraction about 1.45 to 1.5 to get my 20 percent extraction. I got 1.9 at eleven, at its coarsest setting. Coffee was good. It was sweet. No real bitterness. It kind of freaked me out.

[00:15:08]
And I think it's because of this design. When you see the coffee on the bed of it, it just chills. It just takes its time. So the amount of water that passes through the ground is extremely slow. So this brewer is perfect for a coarse grind coffee. You can do it with a fine grind, but a lot of times you're going to get over extraction. So you have to play around with that yourself.

[00:15:39]
I can give you a recipe and all that stuff. But at the end of the day it's about you trying to figure it out for yourself, how to use these brewers. The reason why I'm doing all this is because when I'm thinking about coffee, I always have this engineering background lingering in the back of my head, trying to understand why people do what they do.

[00:16:05]
I'm going to be able to see what's the biggest difference. But it's kind of funny when I say this because I can talk about the design. We can see how coffee is manipulated through the water and the shape that it takes. And we can play around with different filters and all that stuff.

[00:16:24]
But at the end of the day the coffees still mimic something comparable to each other. But at the end of the day with the Hario V60, with the Deep 27, with any of these that we're using, the biggest takeaway is to truly understand what you're dealing with.

[00:16:48]
Don't look at any recipes. You just want to look at this video. I can say that right. Just take your time with your devices. See what it's all about because at the end of the day, that's all you have going for you.

[00:17:06]
Those are some of the things that you're trying to think about and analyze and get to the point where you are one with your machine. You understand that if you put this coffee inside of it, if you do this particular technique, you're going to get something magical and you actually understand exactly what you're doing in this whole thing.

[00:17:32]
So I think that's the biggest takeaway. Understand, get to a point where you can really just master making your cup of coffee no matter what you use. Even if it is an Aeropress or French press, Hario V60, a Kalita Wave, Origami. This one's pretty badass. Deep 27 or flat bed brewer. Think about it. Analyze it. See why it works. See why it doesn't work. See which coffees work really well with it and just have fun with it. Alright, every day being, signing off. I'll talk to you later. Bye.