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How Does a Burr Grinder Work?

Early in my coffee journey, I did not really care about coffee grinders. I thought that a bladed spice grinder was enough.

Oh, boy was I wrong.

When I finally took the educated plunge, burr grinders became an essential tool. The difference in grind quality between a blade grinder and a burr grinder was astronomical.

Burr grinders open up different coffee notes and flavors that were not possible with blade grinders. Not only that, but they provide more consistency in your grind.

It is important to know how a burr grinder works to get the most out of one. In this article, we explain to you the mechanics behind a burr grinder, the different burr grinders you can purchase, and the difference between flat and conical burr grinders.

What Is a Burr Grinder?

coffee burr grinder machine

There is a reason why we don’t just add hot water to whole coffee beans—they don’t give out any flavor. Smaller particles awaken the caffeine and flavor inside the bean.

At the same time, coffee beans lose their flavor and aroma when out for too long. They will become stale and lose their flavor. When exposed to air for a long time, they start to oxidize and lose their properties—and may even take in fishy smells.

This is why we use grinders to break up the coffee bean into smaller pieces. It is important to grind your coffee directly when you need it. This ensures the right quality and taste for your cup.

Hot water brings out the flavors of coffee when it is in contact with a larger amount of surface area.

Rudimentary methods of grinding coffee beans were through brute force like a mortar and pestle. Although giving results, this does not guarantee consistency in flavor and grind size.

Early on a coffee journey, you may have used a blade grinder. I am guilty of this too. They just aren’t up to par with burr grinders in terms of reliability.

Burr grinders are mills that grind down small objects—coffee beans—between two moving abrasive materials at a distance that is set by the user. In the case of burr coffee grinders, the materials can be either ceramic or steel.

Adjusting the distance between the two revolving materials determines your grind size. The closer the distance, the smaller the grind size; the farther the distance, the larger your grind size.

When used properly in different brewing methods, this variance in grind size will give you different tastes in your coffee.

How Does a Burr Grinder Work?

ground coffee and roast coffee beans in a portafilters

To get the most flavor out of a coffee bean, you first need to break it up into smaller pieces.

Burr grinders crush the beans by grinding them against two abrasive materials—the burrs. The distance between these two materials gives us our grind sizes.

In hand grinders, it is the movement of the hand that turns the conical burr inside the set circular burr. This movement pulls the beans to the middle of the burrs. The set abrasions on the burrs then break up the coffee into smaller pieces. For hand grinders, the grinds come out and are stored in a plastic detachable pod.

Electric grinders replace the hand movement in hand grinders with the power of an electric motor. When plugged and turned on, the motor drives the middle or outer burr against the set burr, breaking up the coffee beans inside.

Types of Burr Grinders

There are various burr grinders at different price points. Grinders are usually differentiated by their role in coffee making, like espresso versus filter coffee, or whether they are manual or electric.

Hand Grinders

Hario Ceramic Coffee Mill, Mini Slim

Coming in at the affordable spectrum are hand grinders. These burr grinders are usually made out of plastic construction and can hold about 40 grams of coffee. Affordable hand grinders, like the Hario Slim, are perfect if you’re just getting into it.

Comandante C40 MK3 Nitro Blade Wenge

Going up the price scale, you now get steel hand grinders. Steel-cased hand grinders usually provide better grip and long-term durability as compared to plastic hand grinders. Grinders like the Commandante C40 provide amazing grind uniformity and quality, while also providing the ability to grind fine for espresso.

Hand grinders usually come in with conical burr sets. Conical burr sets consist of one conical-shaped burr that grinds the beans against a set circular burr. These burrs allow a larger amount of coffee beans into the burr set.

Affordable hand grinders come with ceramic burr sets, while more expensive ones go with steel burr sets. The difference between the two usually comes down to long-term durability. Ceramic burr sets are cheap to produce and install, but they degrade faster in the long term. Steel burrs last a long time, giving the user peace of mind in day-to-day use.

To adjust a hand grinder, you usually have to turn a plastic knob, either at the bottom of the grinder or the top, clockwise or counterclockwise. This moves the conical burr closer or farther away from the set circular burr.

Hand grinders are the best way to get into burr grinders for your daily coffee needs.

Electric Burr Grinders

If you wake up in the morning and get fed up with hand grinding your coffee, then maybe you need an electric grinder. Electric grinders take away the need for brute force when grinding your coffee and instead replace it with an electric motor. The electric motor then moves the burrs producing your grind.

These electric grinders come with more power-packed features than hand grinders. Some feature timers to help with grinding large batches of beans. Some throw away the timer function and instead place a weight-based function that weighs your beans as they come in the grinder.

Espresso-focused electric grinders come with portafilter holders so that you can get the coffee straight into your basket and straight into the coffee machine.

Filter and Espresso Electric Grinders

Electric burr grinders are usually divided based on their use—filter or espresso coffee. The difference lies in the uniformity of the grind and the power of the motor.

To achieve the fine grind size that is needed in espressos, electric grinders need to have a powerful motor. These motors are usually more expensive to install and maintain, thus the higher price tag of espresso grinders.

Eureka Mignon

Grinders like the Eureka Mignon are focused on espresso. Tweaking the adjustment knob will not get you a grind size big enough for a french press.

Filter coffee grinders do not need this extra power. French presses or V60s do not necessarily need a fine grind size. Because of this, filter coffee electric grinders are slightly affordable compared to their espresso counterpart. The Wilfa Uniform is a great filter coffee grinder at its price range.

Some electric grinders combine the simplicity of filter coffee grinding with the fine art of espresso. Grinders, like the Niche Zero, give the user the ability to grind for both filter and espresso. Of course, these grinders demand a high price for their usability.

Single Dose Grinders

When you enter a coffee shop, you will most likely see a large electric grinder with a big plastic container on top of it. This container usually holds about two bags full of coffee beans.

These containers are called ‘hoppers’ and they are what hold the coffee beans before they go into the burrs.

Coffee shops use large hoppers due to the volume of coffee that needs to be ground at a particular time. Customers usually order bags of pre-ground coffee and this needs large grinders that can hold a sizable number of beans.

Single-dose grinders have become all the rage lately. Since hoppers aren’t sealed, beans kept in large hoppers will be exposed to the air for longer periods. These beans will become stale faster. Single-dose grinders remove this problem by only holding a small amount of coffee when grinding—usually 30-40 grams.

Single-dose grinders are great for home coffee bars where you’re most likely to not use a lot of beans in one go. Due to their small hoppers, single-dose grinders will also use up less space.

Since single-dose grinders need less space for their hoppers, some grinders have installed a bellow system, usually made out of rubber or plastic. This system focuses on a specific coffee problem—retention.

When pressed down, the bellows push air into the grinder, pushing the retained coffee grounds inside the burrs and the grinder body.

Stepped Vs Stepless Adjustment

Adjusting the distance between two burrs is usually done by mechanically moving one burr closer or farther away from the other. Usually, this is done by moving a knob on the grinder.

A stepped adjustment system is set ‘steps’ in adjusting the distance of the burrs. This adjustment system is more common for more affordable hand and electric grinders. Since they are stepped, they aren’t as adjustable compared to stepless adjustments.

Stepless adjustments are exactly what they’re called—they don’t have any steps when adjusting the burrs. This gives the user almost infinite adjustability. This type of adjustment is available with more up-market espresso grinders like the Eureka Mignon.

Difference Between Conical and Flat Burrs

The majority of burr grinders use conical burrs. Whether ceramic or steel, conical burrs take up a lot more beans when in use. They’re the most used for hand grinders since it is the easiest to connect with a hand lever.

Flat burrs rose in prominence in the past few years due to their supposed consistency in grinding. Flat burrs are two burrs that are set closer to each other, as compared to conical burrs. Due to their distance from each other, grinders with flat burrs are more likely to induce ‘popcorning’ in the hopper. Popcorning is the popping up of some beans when the burrs can’t get a grip on them.

Is there a difference in taste between conical and flat burrs? Not so much according to Seattle Coffee Gear. The difference in conical and flat burrs is more on the speed of the grind. Conical burrs accept more beans and thus will take less time to grind. Flat burrs, due to the space between the burrs, take more time to grind the beans.

To Spray or Not to Spray?

Due to electric grinders being usually made of metal, and with the presence of an electric motor, static from electricity may sometimes be present when grinding your beans. Just like when you rub a balloon on someone’s hair and the strands stick to it, the same happens to coffee grounds when coming out of the grinder.

This presents a problem with retention in grinding beans. The accumulated grounds that are stuck could throw off the ratio of your brew and can make your workspace messy.

A quick hack for this is to give you coffee beans a quick spritz of water before grinding. That’s right, water. The water acts as a magnet for the static.

But how viable is this for the long term? What happens to the electronics inside?

Giving your beans a quick spray before grinding will not affect your grinder in any way if you are dosing coffee once a day. The problem arises when you need to pull back-to-back espresso shots and need to spray every single time.

So, if you’re only doing one dose of espresso a day, go and spritz your coffee with water! The difference is night and day.

Check out this video to learn more about spraying water into your coffee beans!

Why Use a Burr Grinder?

So why use a burr grinder?

Blade grinders are cheap and easy to use. You just place the beans inside and turn it on. But the product from these grinders just isn’t up to par with the consistency of a burr grinder.

Adjustability

How do you get a finer grind with your beans when using a blade grinder? You just give the beans another blitz right?

But the way a blade grinder pulverizes the beans yields inconsistent grinds. You can get both large pieces and smaller finer pieces. The smaller pieces will give you the flavor out of the beans, but the large pieces may bring out some sourness in your cup.

With burr grinders, you can expect consistent and uniform grinds from every use. Because the burrs are made to standard measurements, and since they take in beans that they can fit, all the beans are given the same grind.

When using stepless grinders even, you can adjust your grind to even the most minute levels. You just can’t do that with blade grinders.

Long-Term Value

With the metal construction of higher-end burr grinders, you are getting your money’s worth. With either ceramic or metal burrs, you will get better long-term usage out of them instead of a blade grinder.

Burr grinders are versatile enough that they can grind coffee for different brewing methods. Since they’re already consistent with their grind, upgrading from one burr grinder to a more expensive one will give you amazing results.

But that does not mean that even an affordable hand burr grinder will not give you amazing results. For things like French presses or V60s, a simple hand burr grinder is enough of an upgrade from a blade grinder.

You also can upgrade the burrs in your grinder. Companies like SSP provide high-end burrs with low retention. The option to just change out your burrs when they get worn out just proves the longevity of burr grinders.

Final Thoughts

Burr grinders are one of, if not, the best investments you can make for your coffee journey. The range in burr grinders is endless, and the uses are infinite. From simple hand grinders to expensive multi-purpose electric grinders, you are sure to find a burr grinder for your brewing needs.

Avatar for Giada Nizzoli

Born in Italy but currently brewing from the UK, Giada is a highly-caffeinated coffee expert with a soft spot for espressos. She worked in cafés for years and has recently fallen in love with the practical Kalita Wave (just don’t tell her Italian moka pot!).

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