Changing Flavors with the Varia FLO Dripper

Flat-bottom drippers aren’t new to the pour-over world, but when there’s a new one on the scene, I can’t help but be curious. While conical brewers can offer a crisp brew with higher acidity, flat-bottom brewers are known to increase sweetness, enhance body, and accentuate floral notes. In 2024, Varia Brewing released a device that allows coffee enthusiasts to explore the possibilities of a flat-bottom dripper even further.

It’s called the Varia FLO, and it goes the extra mile by allowing baristas the ability to switch between different circular disks known as a FLO Screens on the bottom of the dripper. Each disk will affect flowrate, the way the water moves through the coffee bed, and ultimately, flavor, in unique ways.

A Quick Review of Flat-Bottom Drippers

A flat-bottom dripper is exactly what it sounds like: It’s a brewing device where the coffee bed is flat on the bottom, as opposed to a cone shape. The brewed coffee will come out of the bottom through holes, mesh, or any other kind of perforation. Some of these brewers even have small holes that restrict the flow of the brew, while others depend more on grind size to dictate flowrate.

What is the Varia FLO?

Living up to their name, Varia sought out to add some variability to the classic flat-bottom pour-over. The FLO, which stands for Flexible Liquid Output, is a collaboration between Varia and Japan’s Kurasu Roastery. It comes with 3 FLO Screens designed for Fast, Medium, and Slow flowrates.

Each screen is capable of producing different flavors, even when using the same coffee. For example, the “Fast 1” FLO screen makes a brew with lighter body and impressive clarity thanks to its increased uniformly spaced openings beneath the coffee bed. The “Medium 1” screen aims to reduce bitterness while increasing sweetness accomplished by prioritizing flowrate with openings similar to the Fast 1 screen, but choking flow just a bit more in the center of the screen. The “Slow 1” screen increases body by slowing down the flowrate with its fewer holes, and it can increase acidity too.  

Revisiting Our Varia FLO Review YouTube Video

In case you missed it, we’ve got a video starring Yours Truly all about the Varia FLO, and it even includes some testing with the screens that come in the box. Since my video, we've brought in additional screens in all three categories with new hole patterns and new possibilities for your coffee.

In my video I tested the FLO screens the dripper comes with, but we did find some really interesting results. We used the same coffee, water temperature, grind size, ratio, pouring schedule… you know… everything. All we changed from brew to brew was the FLO screen. I’ll try not to spoil too much and just let you enjoy the video, but I did have a bit of a mind blowing moment. The Fast and Medium screens behaved pretty much the same; even their TDS and Extraction percentages were pretty similar, but each cup tasted completely different! The variation in which the water flowed through the coffee bed at different speeds and temperatures reacted with different flavor and aroma compounds.

Now that even more FLO screens are available, let’s get brewing and test those out too.

More Testing!

In this article, I’ll be diving into each individual screen in detail. That’s seven screens, so I’ll be brewing, testing, and tasting seven different cups. The last time we tested the Varia FLO for our YouTube review, we used three coffees of different roast styles to get the full picture of how the FLO treats each different style. This time, I used just one coffee: Whole Latte Love’s single origin Colombia Tolima. To control as many parameters as possible I also used the same grinder, grind size, water makeup, brew ratio, temperature, dose, and water weight. I did something a little different this time: I used the xBloom Studio to help make sure the pouring schedule is totally consistent. The only variable changed in this experiment, was the FLO screen.

Since there are even more flow screens to play with this time around, I’m gonna be a busy and caffeinated dude. I’ll be assessing a bunch of things, including flavor and technical properties of the brew. I want to know:

• Final drawdown time
• The actual brewed beverage’s weight
• TDS (Total Dissolved Solids percentage)
• Extraction percentage.

I’ll also describe how each brew tastes, focusing on body, acidity, sweetness, aftertaste, balance, clarity, and even bitterness.

I ground all coffee pretty coarse on a Varia VS6 with Hypernova Iridescent Titanium Plated Burrs. I wanted to grind somewhat coarse knowing that I’d be using the same grind size for all FLO screens, so when I change to a screen that might slow the brew down, it won’t take absurdly long. For the faster screens with that coarse grind, I don’t mind a quick drawdown; that usually accentuates acidity anyway, which I enjoy.

I used 15 grams of coffee with a 1 to 17 ratio, and programmed a simple 3-pour brew with spiral pattern at 200 degrees Fahrenheit on the xBloom Studio. I waited for all brews to cool down to about 98 degrees Fahrenheit before tasting or taking a TDS measurement.

And with that, here’s my results…

Stock Screens

Fast 1 (Stock)

Our first test of the Fast 1 screen in our YouTube review gave us great results with a darker roasted coffee. With a high-scoring, very dense washed Java from Untold Coffee Lab, more of those tea-like and floral notes were easier to perceive in this screen. Here’s what we found this time with the Colombia Tolima.

Right away, I can tell that this screen can deliver some additional complexity. I’ve brewed this Colombia Tolima many times, but this is the first time I’ve been hit with a cinnamon note. That note isn’t even on the bag! The orange notes are shining through nicely in this brew. It’s not just an orange note, but more like one of my vices: orange candy (orange Sour Patch Kids are the superior Sour Patch Kid, by the way). Lots of apple mixed with caramel… I might dare say there’s a candy apple note in here. The sweetness is lingering in the aftertaste, but there’s still some nice clarity.

Medium 1

This screen was also in our initial round of testing, and it did a great job getting more fruit flavor out of a naturally processed coffee that was just a bit underextracted through the Fast screen. It also cranked up the body and acidity in that washed Java. Here’s how it treated the Colombia Tolima.

The Medium 1 screen gave our Colombia Tolima a bit more bitterness, but more balance as well. The toasted almond note showed up, and the orange sweetness turned into an orange peel bitterness, reminding me of my favorite cocktail garnish. The sweetness was mainly occupied by a nice grape note here.

Slow 1

Initial testing on the Slow 1 screen doesn’t favor a darker roasted coffee, but it does increase acidity and sweetness in other washed coffees. Here’s what we found this time around with the Colombia Tolima.

The last time I tested this screen, I was skeptical that it could produce any additional acidity. I’m still not entirely sure how it happens, I mean it’s not like I changed my grind size or anything. But even in this test, the Slow 1 screen gave me excellent grape acidity. The body also increased at the expense of clarity, but still a darn tasty cup.

CU of coffee drip

New Screens

The stock screens were pretty consistent with my previous results, but now, let’s check out how the new screens stack up to the stock screens.

Fast 1 (NEW)

This cup was a bit chewier in flavor while keeping a lighter body. The caramel notes have become more like toffee and the acidity is a bit more muted. There's not very much fruit in this cup, but the sweetness in other areas is keeping this nice and crushable.

Medium 2

That mysterious cinnamon note showed up a bit here again, wrapped around that nice almond flavor. The acidity is pretty low in this cup, and the body mostly consists of some lingering bitterness.

Slow 2

This was a tough cup. The bitterness jumped up for me and sweetness decreased.  I would be VERY interested in how this screen works with a fruit bomb, like an anaerobic natural process coffee. I wonder if it would retain some fruitiness while bulking up the body?

Slow 3

The Slow 3 screen produced a superbly balanced cup. The acidity was as vibrant as the Slow 1 screen, if not more so. Bitterness is much lower, and the clarity is as nice as the faster screens. While I maintain there is great balance here, that grape acidity was the star of the show.

Test Results as Interpreted by a Barista (Me)

I wasn’t surprised to see low extraction (the Specialty Coffee Association says that typically anywhere between 18% and 22% as well-extracted). I mean, I ground my coffee pretty coarse, after all. I was, however, surprised to see how similar most of the drawdown times were. With the exception of the Slow 1 screen, all drawdown times were within 7 seconds, and after seeing that, it wasn’t much of a surprise that the extraction percentages were so similar too.

The biggest surprise, however, was that even though all of these screens behaved similarly, so many of the cups tasted very different from each other. This is consistent with the first time I ran some tests on the stock FLO screens, and my theory is still that the water flows through the coffee bed differently depending on the hole pattern and shape of the opening.

Final Thoughts

The Varia FLO offers more variation to the world of flat bottom brewers. When I’m dialing in a new coffee, I usually play with many different variables, and the device being used is part of that. With so many FLO screens to choose from, there’s even more possibilities to explore with each new coffee I bring home. Because of this potential of unlocking new flavors, I wouldn’t be surprised to see the Varia FLO become a bigger presence on the national and international stages in Barista Competitions as well.

I suppose my next challenge will be to figure out exactly WHY the FLO screen patterns produce unique flavor profiles. Another challenge for myself: figure out what varietal, processing method, and roasting style best accompanies each of these FLO screens…

But this is probably enough for today.

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