Why Use a Burr Grinder?

What is the Difference Between a Blade Grinder and a Burr Grinder

A decent coffee grinder is essential to making good coffee. In fact, the quality of the grind is almost as important as the quality of the beans. When it comes to coffee grinders, there are two basic kinds: blade grinders and burr grinders. Burr grinders are undeniably the better of the two, but they are also considerably more expensive. So is investing in a burr grinder worth it? Understanding the differences between the two will help to determine which is the best choice for you.

Blade grinder blades

Blade grinders chop up the coffee beans

Blade Grinders

The most common kind of grinder among home users is the classic blade grinder. Blade grinders use a spinning blade to chop up the beans, not unlike a blender. These kinds of grinders are attractive because they are inexpensive, readily available, and simple to use. However, they have several shortcomings:

  • When coffee beans are roasted, they are heated to just the right temperature; overheating them is detrimental to the flavour. Unfortunately, blade grinders make a lot of heat (in the same way some blenders heat up soup). And because the beans remain in the grinder for a relatively long time, they tend to get overheated. This doesn’t necessarily ruin the coffee, but it does affect the flavour.
  • Another issue with blade grinders is that they are notorious for producing an uneven grind. For optimal flavour, it is important that the size of the coffee grounds are uniform. This ensures that all of the coffee is extracted evenly. Also, if you are brewing without a filter (like with French Press), any coffee grinds that are particularly small end up in your cup, creating an unpleasant silt.
  • The absence of settings on blade grinders makes it difficult to repeatedly grind your beans to the same consistency. This lack of control makes it near impossible to adjust the flow rate, thus you cannot fine-tune your coffee.
Burr grinder burrs

Burr grinders shave the coffee beans

Burr Grinders

The alternative to blade grinders are burr grinders. These machines grind the beans between two hard surfaces, the burrs. Burrs are (usually) quite sharp and are made of either hardened steel or ceramic. They can be either conical (like the ones pictured on the right), or flat discs. Rather than chopping the beans, burr grinders use their sharp edges to shave small particles off of the bean. Burr grinders offer several advantages over blade grinders:

  • In a burr grinder, beans are ground quickly and then immediately pass through the burrs (rather than being in continual contact with a spinning blade). As a result, the beans do not get overheated as they do in a blade grinder. This helps produce optimal flavour.
  • Burr mechanisms are designed to be wider at the top, where the beans enter, and narrower at the bottom, where the beans exit. The size of the grinds is determined by the size of the gap at the exit (which is adjustable). This design has two major advantages:
    1. It produces a very even grind, with each particle being fairly consistently sized. This results in a more even extraction and hence better tasting coffee. It also generates less of the very small particles that cause reside and sludge in your cup of coffee.
    2. Because the space between the two burrs is set manually, the grind size can be set and then repeated. This makes it possible to accurately adjust the grind size in order to control the extraction rate, allowing you to fine tune your brewing process. This kind of control is imperative to espresso.

In short, burr grinders result in better flavour and give the user more control.

Should You Invest in a Burr Grinder?

Using a burr grinder will improve the taste of your coffee, no matter how you brew it. With some brewing methods, there are also other advantages. If you are brewing without a filter, particularly French Press, using a burr grinder will result in less sludge and coffee residue in your cup. Manual brewing methods, such as Pour-over, benefit from a burr grinder in a different way; with a burr grinder, you can easily and precisely adjust the grind size and hence control the rate the water flows through the coffee. This allows you to fine tune the taste, but many home users don’t want to get that technical.

While most brewing methods will benefit from a burr grinder, espresso must be made with a burr grinder (and a high quality one at that). This is because espresso is made by forcing water through coffee at high pressure. An espresso machine can only build up the required pressure if the coffee grinds are able to resist the water being forced through. In order to create this resistance,  the coffee beans must be ground very fine and very consistent, which a blade grinder is not able to do. Additionally, to get a perfect cup of espresso, the water must flow through the coffee at exactly the right speed. This can only be controlled if you are able to fine tune the grind size in minute increments, which only a high end burr grinder is capable of doing.

(Note: With any rule there are always exceptions; and this is true of the “espresso requires a burr grinder” rule. Espresso machines that use a pressurized portafilter can get away without using a burr grinder)

Whether you should use a blade grinder or a burr grinder depends on how you brew your coffee and the quality of beans that you buy. If you are using an inexpensive automatic drip brewer and not so fresh grocery store coffee beans, a blade grinder should work just fine. On the other hand, if you are buying freshly roasted beans and have invested in a good brewer, then investing in a burr grinder is definitely worthwhile.




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