July 25, 2022

Which material should your grinder burrs be made from?


It’s widely known in the coffee sector that if you want to make great espresso, you need more than just a high-end espresso machine – you also need a high-quality burr grinder. 

Burr grinders provide more consistent and even particle size distribution than blade grinders – resulting in better extraction overall.

A number of materials are used to produce grinder burrs, including plastic, ceramic, and metal. However, as the coffee grinder market has evolved in recent years, there has been an increasing focus on burrs made from higher-quality materials. 

Plastic, ceramic, and metal burrs all have a number of pros and cons, but which material performs the best?

To find out, I spoke with two coffee professionals from Fiorenzato, a premium coffee grinder manufacturer. Read on to find out what they said.

You may also like our article on cleaning and maintaining your coffee grinder.

ground coffee and a steel flat burr

Blade vs. burr grinders

We all know the importance of investing in a good grinder, whether in a coffee shop or at home. For home consumers, grinding fresh for each cup is an essential part of producing delicious coffee that gets even remotely close to café-level quality.

It’s important to note that while there are different types of coffee grinder, not all of them are manufactured to the same quality standards.

With a blade grinder, the beans are placed in the grinding chamber before a small propeller blade at the bottom of the chamber rotates at a high speed. This chops the beans into smaller pieces. 

However, these high grinding speeds often expose the coffee grounds to excessive heat and static which increases the likelihood of clumping. Furthermore, the grind size is solely controlled by grind time, and consistency is difficult to achieve.

Although there are some ways to improve grind consistency with these grinders, it is still arguably impossible to achieve the same high-quality results as with burr grinders.

Giulia Bagato is the Marketing Manager for Fiorenzato.

“Blade grinders cannot guarantee the same grind quality as burr grinders,” she says. “This is because blade grinders chop up the coffee beans in a rough and irregular way.”

Ultimately, inconsistent grind size means there is a mix of large and small particles, which will most likely result in coffee which is simultaneously underextracted and overextracted.

“With blade grinders, it’s almost impossible to get the correct grind size for espresso,” Giulia tells me. “Burr grinders, however, crush the beans into consistently-sized particles [and can grind coffee for a number of different brewing methods].”

Flat and conical burrs are both used across high-end grinder models. These burrs can also generally be adjusted to set a wider range of grind sizes. With burr grinders, the distance between the burr sets determines the grind size. 

Both flat and conical burr grinders work by crushing the beans between the two burrs to produce the required grind size. Flat burrs are made up of two evenly-sized rings which lie flat on top of each other, whereas conical burrs include an outer circular burr and a cone-shaped inner burr.

Giulia explains why burr grinders are considerably better than other options on the market.

“Grinding for espresso requires the right amount of fines and boulders, also known as bimodal distribution,” she says. 

For espresso extraction, there generally needs to be a larger amount of fines to make up for the reduced brewing time.

“Anyone who wants to make good espresso at home, or just wants to achieve quality and consistency when grinding for any brewing method, should consider investing in a burr grinder,” she notes.

The grinding chamber and bottom burr of a Fiorenzato grinder

Which materials are used for burr grinders?

Chiara Nalin is the Quality Assurance Manager for Fiorenzato.

“There are many electrical and mechanical components in a grinder, such as the microswitch and inverter,” she says. “But if you want to achieve the most optimal grind size for your brewing method, you need to first look at a number of specific brewing parameters.

“These include flow rate, total extraction time, and dose,” she explains. “It’s important to weigh up these parameters before you look at your grinder to ensure a consistent and even particle size distribution for extracting high-quality coffee.”

There are many different materials used for burr grinders for both commercial and home use. Plastic and ceramic burrs are more common in lower price point manual hand grinders. While these options are more accessible and affordable, they are often less consistent.

Generally, plastic and ceramic burrs are more resilient than other materials, and can retain sharpness for around twice as long as general stainless steel burrs. However, ceramic and plastic burrs are significantly less sharp than steel burrs to begin with.

What’s more, ceramic burrs are brittle and can easily break if there are any small stones among the coffee beans, for instance.

Steel burrs (including those made from stainless steel and brushed carbon) are more commonly used in commercial-grade grinders and premium home grinders. This is because they typically result in a more consistent and even grind size than other materials.

opening the mechanism of a steel conical burr coffee grinder

Exploring steel burrs

Although steel is the most common material for grinder burr manufacture, Chiara explains that there are a number of different types of metal.

“There is no one particular type of steel, so it’s important [for coffee shop owners and home consumers] to consider the various requirements of high-quality steel options,” she says. “The steel must be food-grade because the burrs come into contact with the coffee, so the health of the consumer must be a priority.”

She explains: “Steel burrs should also be resistant to wear and tear – as well as corrosion – and be tough and durable.

“The material that Fiorenzato uses for its burrs is one of the strongest metals available for coffee grinders,” she adds. “This material is known as ‘M340’, which is a specific alloy made from carbon, nitrogen, and silicon, [as well as other compounds].”

Ultimately, the stronger the steel is, the more hard-wearing it will be. This means it will retain its sharpness for much longer, even when grinding larger amounts of coffee over a longer period of time – which is important for busy coffee shops.

Steel burrs also tend to retain more of the heat produced during grinding when compared to plastic and ceramic burrs. This can cause the ground coffee to increase in temperature too, which can lead to aroma and flavour loss, as well as increasing the chance of clumping.

“The steel used in burrs must be resistant to heat absorption so that it can withstand the increase in temperature,” Chiara says. “There are different grades of steel alloys that can be used for this. For instance, one of the most common alloys is a case-hardening steel known as ‘16NiCr4’.”

Coffee puck inside a portafilter

Optimising extraction

Chiara explains that as well as burr material, size and shape are two other important factors to consider when choosing a grinder.

“[Coffee shop owners] need to select the most appropriate burr diameter for their business,” she says. “They can do this by calculating the volume of coffee they extract on a daily basis.”

This is also an important consideration for home consumers.

“Over the past few years, there has been a rise in the number of home baristas – people who want to replicate the coffee shop experience at home, or experiment with new recipes and brewing methods,” Giulia says.

“For this reason, many companies have created premium home coffee grinders, including the AllGround from Fiorenzato, which includes the same components and technology as commercial grinders used in coffee shops.”

She adds: “The AllGround uses titanium-coated 64mm Bohler M340 steel burrs, which is the same material and burr size used in all of Fiorenzato’s professional coffee grinders.

“After extensive analysis and comparisons, we chose Bohler M340 steel as it guarantees higher resistance to corrosion and wear and tear, as well as a higher food safety grade,” she tells me.

No matter how strong or durable your grinder is, it’s essential that you clean and maintain your burrs on a regular basis. Clumping and grind retention can lead to blockages in your grinder – potentially causing damage and making your coffee taste stale.

Coffee grounds in a paper filter

If you want to get the most out of your coffee, investing in a high-quality grinder is essential. Considering the material the burrs are made from is an important aspect of this decision, as it will ultimately influence how your coffee extracts.

There are a number of advantages and disadvantages to each of the materials used for grinder burrs, but it’s widely accepted that steel burrs result in the most consistent and even particle size distribution. Ultimately, depending on your brew recipe, this can help you to achieve better results in the long run – and drink better-tasting coffee as a result.

Enjoyed this? Then try our article on coffee grinder burrs: What should home consumers look for?

Photo credits: Fiorenzato

Perfect Daily Grind

Please note: Fiorenzato is a sponsor of Perfect Daily Grind.

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