Conical vs Flat Burr Grinders: How To Choose

Learning about burr types can feel daunting on top of everything else that goes into shopping for your coffee setup. It can be very confusing trying to understand how conical and flat burrs actually affect the taste of your coffee. It’s also tricky to pinpoint what the best burr type is for espresso, as a lot of opinion on this has shifted in recent years. We’re here to help you understand what sets these different burr configurations apart and help you select the right grinder for your countertop.

What Are Burr Grinders (and Why Do They Matter)?

Burr grinders are a must for specialty coffee. To understand what sets burr grinders apart from blade grinders it’s important to understand how the chemistry works. When hot water passes through coffee grounds it bonds with coffee molecules, giving you that delicious cup. Uniform surface area is key for even extraction of the coffee, as uneven, chopped beans extract at different rates, resulting in a bitter or sour cup of coffee (depending on temperature and other factors). Blade grinders create these sliced up, uneven beans. Burr grinders, on the other hand, use surfaces specially designed for uniformly smashing and grinding the beans in a single pass through the grind chamber. This results in much more uniform, consistent grounds that will aid that chemical extraction process.

How Conical Burrs Work

Conical burs use an outer ring with an inner, cone-shaped burr that rotates. Beans are fed in between the ring and the cone from a hopper using gravity, grinding as they pass through the rotating surface. These grinders tend to run a little less hot due to their lower RPMs, and this can also help preserve certain aromatic qualities of the beans. Most important for taste, however, is the consistency of the “fines” that these grinders produce. Fines are grounds that are a bit off of the target setting. This “inconsistency” does still occur in burr grinders, but in the case of conical configurations those secondary fines can actually provide a richer, deeper cup thanks to their uniformity. These types of burrs are also lower retention than flat configurations, meaning that less coffee grounds get stuck in the chamber.

How Flat Burrs Work

Flat burr configurations are two flat, disc shaped burrs stacked on top of one another with a gap in between. Beans are fed through the center and then move outwards as the burrs rotate. These types of burrs generally run hotter due to their higher RPM, which can cause some clumping. Most modern flat burr grinders use some sort of anti-clumping techniques or cooling systems to mitigate this. These types of burrs generally produce fewer fines at the cost of that higher heat and higher retention due to the flat horizontal surfaces.

Conical vs Flat Burr Grinders: What's Actually Different in the Cup?

Flavor Profile

The most important question to be answered here is how do these different types of burrs really affect coffee. First, it’s important to understand that the difference between these types of burrs is not huge - you likely won’t really notice until you have a well developed palate. With that in mind though, due to the higher number of fines produced by conical burrs, they are associated with richer, rounder brews featuring a bit more sweetness. Flat burrs, by comparison, produce less fines and result in a clearer, cleaner cup that brings out more of the beans’ delicate flavor notes.

Noise and Heat

Conical burrs run at a lower RPM, which makes them a bit quieter and lower in heat production. This is noticeable enough to make a difference in a shared living space, especially for those early morning cups. Flat burrs are a bit noisier and run hotter due to their higher RPMs, but the heat is usually well managed by modern grinders. Even without cooling systems or anti-clumping, the heat a home burr grinder produces is negligible for the most part, so it’s not something you should worry too much about.

Grind Retention and Single-Dosing

Conical burrs retain fewer grounds because of their design. Since gravity is the main force pulling the grounds through, fewer tend to get stuck in the chamber. Flat burrs, on the other hand, can cause grounds to get stuck in the chamber. While many modern grinders use techniques to mitigate this, the rule of thumb here is that conical is the way to go if you plan to single-dose your beans. Flat burrs are fine for regular use, as the retained grounds are generally pushed out when you grind your next dose.

Price and Accessibility

Conical burr configurations tend to be the standard for entry- and mid-level grinders. Their simple design and less need for anti-clumping and retention technology makes them easier and less expensive to produce. Flat burrs require more precision in their engineering due to their parallel alignment, and therefore usually start at a higher price point. Generally you’ll find that any manual or hand grinder that you buy will be conical due to their nature.

Best Burrs for Espresso

There’s no simple answer to which burr type is better for espresso. Flat burrs tend to bring out more of the delicate notes of the bean, and result in a “cleaner” shot. We often recommend them for users who like to brew a lot of single origins and light roasts, which are typically appealing due to their unique tasting notes. Conical burrs are great for darker roasts and more consistently rich/sweet shots. As you might expect, this also means that conical burrs tend to be a bit easier to dial in, partly due to the burrs being a bit less sensitive to small adjustments. Finally, conical burrs tend to handle the switch from espresso ranges to more coarse settings for slow brewed coffee a bit better. Both types of grinders fit well for a different type of coffee drinker.

Best Burrs for Filter Coffee (Pour-Over, Drip, French Press)

While conical burrs are easier to work with in coarser settings, flat burrs do tend to shine for drip and pour over brew methods. This is because of the aforementioned tendency for flat burrs to bring out more direct flavors from coffee beans themselves. Conical burrs work a little better for brew methods like french press and cold brew, primarily because the extra fines can add body to these brew methods. In reality though, both sets of burrs can brew excellent coffee for any slow brew method. The key thing to know is that purpose-built espresso grinders often don’t feature an adjustment range that performs well at coarser settings (with the opposite being true for grinders not built for espresso). As such, we always recommend ensuring that your grinder is designed to work well with whatever brew method you’re using.

Shop Grinders at Seattle Coffee Gear

At Seattle Coffee Gear we carry a wide range of conical and flat burr grinders across budget tiers. We also list our grinders by brew method, making it easy to find the right fit for your countertop. If you’re still unsure after browsing, our support staff and gear advisors are here to help you make the perfect purchase.

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