So you want to buy a coffee grinder? You've come to the right place. In this guide, we'll go over what is essential to look for and how it might fit your coffee routine.
Bias disclaimer: Yes, we are a company that sells coffee equipment. However, this guide will generally apply to most coffee grinders, allowing you to make your own purchasing decisions. If you want specific product suggestions based on what we sell, we'll have those at the bottom :)
Let's start with burrs; we get the most questions about these by far. Blade grinders, also referred to as helicopter grinders, do not offer a uniform particle size for grinding coffee. These aren't suitable for grinding coffee.
Now we can talk about burrs. These come in a couple of different varieties: conical burrs, flat burrs, ghost burrs, and fake burrs. For our purposes, we'll cover ghost burrs only briefly. They're toothed burrs of a somewhat vintage variety. Mostly not used anymore, they do have perks in light dust creation and uniform grinding.
Now, fake burrs, these are tricky. Also known as false burrs, are made through a process called powder metallurgy. You take a bunch of metal dust and squeeze it into a mold, before superheating it to fuze the dust into solids. There's one major problem here, and that is this process doesn't create very sharp edges for grinding coffee. They often have teeth sticking out, pulverizing the beans, and aren't conducive to even particle distribution. Most of these grinders will be under $200CAD, so keep an eye out in your shopping travels.
Now that we've been over the other two, let's get down to the brass (or should we say hardened steel) tacks on conical and flat.
I want to stress, first and foremost, this is nitpicking. There's very little research on which is better, and most of what you'll hear comes from the ever scientific source of "experience." A conical and flat burr grinder of equal quality will make you a delicious coffee cup, and we'd wager a guess that 95% of the home-coffee aficionados could not tell you the difference in a blind test.
So conical burrs. The mainstays of the conical burr argument are low heat and bi-modal distribution. Due to the increased mass of metal and more grinding surface, conical burrs spin slower to grind the same amount of coffee. This is helpful in commercial settings mostly, where you're grinding several shots per minute. It's less useful in a home environment, as you'll likely not grind so much coffee that friction heat comes into play. Conical burrs are bi-modal, which means they grind two sizes of beans. Finer grinds, and coarser grinds. The finer grinds slow down the extraction of the coffee to help saturate and extract the larger grinds. Conical burrs also have two-axis where they need to be parallel - an added manufacturing complexity. Added complexities are a problem for affordable grinders trying to keep the price down, and conical burrs are usually more expensive to replace than flat burrs.
Let's move on to flat burrs. We have some big words to throw around here as well, namely retention and thermal transfer. Flat burrs generate more heat, as they need to spin faster to grind the same amount of coffee as a conical burr. Flat also has the potential for more retention, although we've found this is more up to the grinder's anti-retention features and construction than the burr type. Flat burrs are unimodal, and a such, they produce one consistent grind size that will aid in extraction. All of that said, flat burrs are cheaper and easier to manufacture, so service down the road can be more affordable, and grind quality at lower price points can be better.
A quick note on ceramics: Burrs typically come in either ceramic or hardened steel. Ceramics do hold an edge longer but are prone to breaking and have inherently more play than hardened steel. We generally recommend hardened steel for most applications, due to availability, durability, and cost.
Here's the kicker, does it matter? Well, no, not really. Unless you're competing at the competition level or setting up a cafe, all of these differences are mainly negligible. The bottom line? Conical and flat is a matter of preference for most people. Bigger is better for burrs, allowing for better grind uniformity. Retention should be inspected first hand if possible, and determine how much is too much for your personal use. Coffee geeks tend to act like any retention is roughly as bad as the apocalypse. Don't forget to make sure you have a local service center for whatever equipment you buy.
Now that the messy topic of burrs is out of the way let's focus on motors. We're going to talk about watts, RPM, and direct drive. Watts is how much power a motor is capable of consuming, and larger numbers are better. These can range anywhere from about 150W up to 1.5kW or 1500W! That's a crazy amount of power, so what can it do? The more motor a grinder has, the slower it can turn the burrs to grind the coffee without stalling, also known as torque. Generally speaking, you want lower RPM's that produce less heat.
The other primary consideration is the transmission, how the grinder transfers that power to the burrs.
The most entry-level grinder will have a geared system, where the motor's speed is reduced through a gearbox, allowing a slower spinning speed for your burrs and less heat build-up. However, the gears often wear, and won't give you the same life span as direct-drive grinders. Finally, you have direct-drive grinders. Extremely high quality, the powerful motor will directly turn the burrs. In the direct-drive category is belt-driven, in which a belt goes from the motor to the burrs, just like your car. Most commercial grinders will use a direct-drive or belt-drive system, as this allows the most direct power delivery and, depending on the motor spec, the slowest turning burrs.
To finalize, you should be on the lookout for a gearbox or ideally direct-drive motor, with available parts for service.
And now we've reached adjustment. Adjustment is how you change the grind size from fine to coarse. There are two predominant systems; stepped or stepless. Stepped grind adjustment locks you into incremental "steps" or movements in grind size. They won't lose calibration over time because they lock into the grind setting. The caveat here is that sometimes the steps are too big, and you can't find that perfect grind size that could sit in between two steps. Stepped grinders are very user friendly and typically have reference numbers to switch between grind times quickly.
Now stepless grind adjustment sets out to solve this problem. There are no locks or clicks; you can continue to smoothly turn the grind adjustment wheel to a theoretically infinite amount of grind sizes. The benefit here is precision when adjusting, which is particularly handy for espresso, as the grind adjustments can be so minute. Usually, the adjustment speed, or how fast you can change between brew method grinds, is slower, and due to the lack of steps, it's a little difficult to understand for new baristas.
The other consideration with grind adjustment is how easy it is to recalibrate or service. You'll probably have your grinder for a long time, and doing some of the simple service steps yourself can save you some serious cash.
And that concludes our analysis.
TL;DR You should be looking for a hardened steel burr grinder, either conical or flat, with a gearbox or direct-drive motor. If you're doing primarily espresso, strongly consider stepless grind adjustment additionally.
For the All-Purpose Grinder (Stovetop to French press)
For the Espresso Enthusiast: