Coffee Grinding Mistakes You Might Be Making (And Why Your Grinder Matters More Than You Think)

Many home coffee enthusiasts think it might matter more to upgrade your espresso machine over your grinder, but this is a common misconception! While your machine is very important to consistently pulling quality shots, your grinder is actually a bit MORE important. This is especially true if you’re relying on a cheap blade grinder for espresso. In fact, if you’ve had a bad experience with home espresso and were trying to get by with one of these grinders, we can promise you that it’s worth another shot with a purpose built grinder (pun very much intended).

What We Cover in This Video

In this video we discuss the following:

• Should you upgrade your grinder or espresso machine first? The answer might just surprise you!
• What really separates blade grinders and burr grinders.
• How conical and flat burrs affect flavor.
• Why blade grinders just don’t work for espresso.
• What the size and cost of a commercial grinder really gets you.
• The reasons why slow brew methods like drip and cold brew can get by with less precise grinders.

Blade Grinders vs. Burr Grinders — What's Actually Different

Most coffee drinkers have encountered a blade grinder at least once. These grinders use a fixed blade to smash and slice the beans, spinning like a blender. While you can shake and smack the grinder to break up the large chunks, you’ll never get a consistent grind out of these grinders’ repeated contact with the grounds. A burr grinder, by comparison, uses specially formulated flat or conical burrs to grind beans into consistent grounds with a single pass through the chamber. The result is a smooth grinding process that produces grounds that are what you actually need for brewing. This is because a consistent grind size is what aids the chemical process of coffee extraction. As the hot water passes through the bed of grounds it bonds with molecules in the coffee. Consistent surface area on your grounds means that the water evenly extracts those coffee molecules, creating a smooth cup. Inconsistent grounds lead to under- or over-extraction, giving the finished product a sour or bitter taste respectively.

Cone Burr vs. Flat Burr — Does the Shape Change the Flavor?

While the shape of your burrs doesn’t have a massive effect on flavor, there are some differences to note. Conical burrs produce more fines, which can lead to richer extraction. Fines are those grounds that come out on the fine end of the grind, and happen even with more consistent grinds from a burr grinder. The good news is that while some users go so far as to sift out the fines for their brew, they generally don’t have a negative impact on flavor. That said, if you do want a brighter cup and want to take every step to get there, flat burrs do produce fewer fines and will help with a thinner, brighter cup.

Why You Can Actually Adjust a Burr Grinder (and Can't Adjust a Blade Grinder)

One absolute necessity for espresso in particular is the ability to adjust your grind size. With a blade grinder this is impossible, as you can’t change the way the blades rotate in any way. Yes, you can shake the chamber, pulse the blade, etc., but you’re not really controlling the final product much this way. With a burr grinder you can adjust the distance between the burrs to control grind size. By rotating the control mechanism (usually a dial), you’ll work a screw or gear mechanism that moves one of the two burrs up or down to adjust that distance, and the size of your grind.

Home vs. Commercial Burr Sizes — Does Bigger Mean Better?

This is a tricky question. In general, the main difference between home and commercial grinders is burr and motor size. Home burs are usually in the 40-65mm range depending on whether they’re conical or flat. Commercial burrs generally start at 64mm or so and can go up above 80mm. Commercial grinders also use larger, heavier duty motors to both move the larger/heavier burrs, and hold up to the constant use that they see in a commercial environment. The thing about burr size is that it doesn’t generally have a major effect on consistency. Instead, larger burrs grind beans much faster, especially when paired with a larger motor. You can also expect a commercial grinder to last longer on average, but a grinder for home use will likely work for many years anyway, so this benefit is less meaningful.

Does Your Brew Method Forgive Grind Mistakes?

Pressurized brewing, or espresso more specifically, demands a high degree of consistency for its grounds. This is because the water being pushed through the puck of grounds needs consistent, correct backpressure for effective extraction. A pressurized portafilter basket can help with this, but you simply will not be able to get away with a blade grinder for brewing espresso. Pour over is another method that rewards grind consistency - it’s not as demanding as espresso, but ultimately the grind is the pivotal variable in the coffee brewing process with any method, and there’s no reason to take the time to make a pour over with sub-par grounds. Drip brewing and cold brew work better if you’re in a pinch and only have access to a blade grinder. While ultimately the chemical process of drip brewing is very similar to a pour over, this more hand off brew method doesn’t demand as much attention or effort. Cold brew in particular is perfect for a batch of blade grounds as the consistency is much less important than in other methods. This is primarily because of the long brew time, which gives the water plenty of exposure to the grounds and evens out the inconsistencies discussed above.

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