One often overlooked aspect of creating a good coffee is the quality of the grind. A poorly calibrated coffee grinder will create a non-uniform grind size, which can result in undercooked or burnt tasting coffee.
Most coffee grinders can be easily adjusted and calibrated by turning a small rotating ring or dial, usually found on the top or bottom of the grinder. In general, rotating the ring or dial clockwise will result in finer grind size, and rotating anti-clockwise will result in coarser grind size.
In this article, we’ll look at the step-by-step process of adjusting your coffee grinder, explore the reasons why it’s important to keep your grinder well-calibrated and learn what the signs of a poorly calibrated grinder are so that you can tell if your grinder is overdue a little adjustment.
Why It’s Important to Calibrate Your Grinder
Calibrating your coffee grinder is super important. Without regular calibration, your grinder may slacken off or tighten up over time, altering the size of the grounds resulting in bitter-tasting or burnt coffee.
Here are some of the potential side effects of a miscalibrated grinder:
1. Too Fine Grounds
If your coffee grinder is too tight, you will end up with over-extracted, bitter-tasting coffee.
This happens because an overly tight coffee grinder will create finely powdered grounds which have a larger surface area than coarser grounds, leading to over-extraction of the bitter coffee compounds and oils that give coffee its taste.
Finer grounds are easier to burn and add a bitter taste to your finished coffee.
2. Too Coarse Grounds
Over time, coffee grinders tend to slacken off, creating larger, coarser grounds than you might want.
Large grounds are more difficult to extract the flavors from, resulting in weak, sour-tasting coffee even if you lengthen the brewing time.
3. Non-Uniform Grounds
Over time, your coffee grinder may start to produce non-uniform coffee grounds, meaning you will end up with a mixture of coarse grounds and finely powdered grounds in the same coffee.
During the brewing process, the water extracts oils and coffee compounds from finely ground coffee much quicker than it does from larger coffee grounds.
If your grinder is producing a non-uniform ground, your coffee may end up with a mixture of burnt or over-extracted coffee from the fine grounds, as well as weak, sour-tasting coffee from the larger grounds.
How to Instantly Fix Non-Uniform Grounds without Calibrating Your Grinder
One quick solution to instantly fix non-uniform grounds is to use a tiered sieve. This tool is made up of multiple sieves stacked on top of each other (usually three) with ever-decreasing apertures.
Simply pour the uneven coffee into the top sieve and shake it through until the grounds are separated into three uniform sections.
The top section will be full of larger grounds, the bottom will be finely powdered and the middle will be somewhere in-between, so you can choose to use whatever one suits you.
Best Sieve for Coffee
Although there are expensive coffee-specific sieves available, a simple tiered sifting sieve is an inexpensive option that will work just fine.
How Often to Calibrate Your Coffee Grinder?
Different types of coffee grinders need to be adjusted at different frequencies. Some hand grinders can last for years without any adjustments, while some commercial espresso machines must be calibrated several times in a single day with heavy use.
Here is a rough guide to how often different grinders need to be adjusted.
| Type of Grider | Adjustment Frequency |
| Manual / Portable Grinder | Every few weeks |
| Electronic Grinder | Every week |
| Commercial Espresso Machine | Every day |
Signs Your Coffee Grinder May Need Adjusting:
1. Uneven Grounds
If you spot uneven grouds coming from your coffee grinder, it may be a sign that you need to tighten it up a little bit to get rid of those larger grounds and to make your grounds a more uniform size.
Uneven, non-uniform grounds are a big problem since it’s not possible to adjust the brewing process to account for both the fine particles and the large particles.
2. Grounds Too Large
If your coffee grinder slackens off over time, eventually you will notice the particle size getting larger and larger.
This will result in sour-tasting coffee due to under-extraction.
While it’s possible to overcome this by lengthening the brewing process, it’s a simple process to adjust your grinder instead.
3. Too Fine Grounds
Although fine grounds are desirable in espresso brewing, in a regular coffee grinder fine, powdered grounds are a sign that your grinder is too tight.
Finely powdered coffee leads to intense bitter flavors as the water can extract a lot of coffee compounds from the large surface area of a fine powder.
Most manual grinders have a conical burr design, which can be easily raised or lowered to increase or decrease the particle size.
4. Taking Too Long to Grind
When your coffee grinder is taking longer than usual to grind your coffee beans, it may be a sign that the grinder is misadjusted and needs to be calibrated.
This usually happens on flat grinders like the ones found in espresso machines.
5. Stuck / Seized Grinder
Over time your grinder may become stiff and difficult to turn. This may be because of coffee becoming stuck in the burr, or the metal parts of your grinder warping over time.
The first step to fix a seized grinder is to take your grinder apart and clean out any coffee with a dry brush.
If your grinder is still difficult to use even after cleaning, the burrs or blades may be blunted, or the grinder may have become warped.
In some cases, it’s possible to buy a replacement part, but grinders are so cheap these days that it’s often cheaper just to upgrade your grinder.
Need to replace your grinder?
The best option for replacing your coffee grinder is to get a standalone electronic burr mill. This will give you a much better grind than a cheaper blade-based grinder and they aren’t much more expensive.
6. Unusual Noises
Clacking, grinding, or scraping noises coming from your coffee grinder are an indication that your grinder is miscalibrated and needs to be adjusted.
A burr mill should be quiet, unlike a blade or flat mill. If you hear noises coming from your grinder, it may need to be cleaned, adjusted, or replaced.
Burr vs Blade Coffee Grinders
There are two main mechanism types found within coffee grinders, burr grinders, and blade grinders. Each has its own pros and cons. Before you adjust your grinder, it’s important to understand what type of grinder you have.
Here are the two main types of grinding machines and how to tell them apart:
Blade Grinders
Blade grinding mechanisms are often found in lower-end electronic stand-alone coffee grinders and are usually made of two or three sharp, rotating blades attached to a motor.
The blades spin quickly, chopping the beans into small pieces like a food processor.
Blade grinders don’t usually produce a uniform grind due to the chaotic nature of the process, so if you’re not happy with the results you’re getting you may choose to upgrade to a burr grinder which will give you a much finer, more uniform grind.
Burr Grinders (Flat or Conical)
A burr grinder is made up of two metal plates covered in sharp grooves called burrs. There are two common shapes for burr grinders, which are conical and flat.
Both systems work in the same way, forcing the beans between the two plates, where the burrs grind them up and the finely ground powder passes out a small gap between the two plates.
Most coffee grinders will be burr grinders. If you’re not sure, and you don’t see any blades, it’s probably a burr grinder.
Burr grinders create finer grounds of a more uniform size. They are simple to adjust, usually with a ring or dial on the top or bottom of the grinder.
How To Adjust Your Coffee Grinder
Most coffee grinders have a rotating dial or ring which can be rotated to adjust the distance between the two plates of the burr, thus changing the particle size of the grounds. Adjust your coffee grinder by rotating the dial or ring clockwise to make the grounds bigger, or anticlockwise to make them smaller.
In case you’re stuck, here’s a step-by-step guide going over the entire process:
1. Analyze Your Grind
Before you can adjust your grinder, it’s important to diagnose exactly what the problem is. Grind a small handful of beans and check the grounds for coarseness and uniformity.
Take note of the position the dial or ring is at, as it will save you time later if you have a starting point. Most grinders have a number or marker you can read somewhere by the adjustment ring.
You may choose to use a fine coffee sieve for this, especially if you’re checking for uniformity. There are some tiered sieves that can filter your grouds into different sizes so you can easily check for uniformity.
Analyze your coffee
If you really want to perfect your grind, consider picking up a tiered coffee sieve. The Kruve Coffee Sifter has five separate sieves and a calibration guide, helping you test not only the size of your grind but the uniformity too.
2. Empty and Clean your Grinder
Empty out any beans from your grinder, and make sure you rotate the grinding mechanism fully until no more grounds come out.
This will ensure no coffee remains stuck in the burr while you’re trying to adjust it, and that the coffee you check after adjusting is only from the new setting.
Do not skip this step!!
Cleaning out your grinder is especially important if you’re trying to get a coarser grind, since fine coffee powder can easily slip through the grinder even once you’ve adjusted the settings, making it look like it’s misadjusted when it isn’t.
3. Add Fresh Beans and Adjust the Grinder Dial
Add a fresh batch of beans and adjust the grinder appropriately, depending on what the original setting was and what outcome you want to achieve.
On most grinders, turning the dial or rotating ring clockwise will give you more finely ground coffee, and rotating it anticlockwise will give you coarser grounds.
Don’t move the dial too much, just a little bit in either direction so you can analyze the results.
4. Analyze And Repeat
Continue to slowly adjust your grinder and analyze the results until you get to where you want.
Remember to turn the grinder until no more grounds come out each time before you try the new settings, since some smaller grouds may still be stuck in the burrs from the last iteration.
At this point, you may notice that no matter how you adjust the settings, you can not get uniformly-ground beans from your grinder.
If this happens, unfortunately, it means your grinder burrs have become worn and will need to be sharpened by a specialist, or replaced.
For most cheaper grinder models, this will only happen after a few years and it’s probably cheaper just to buy a new one. You can get an excellent burr grinder on Amazon without breaking the bank.
Need to replace your grinder?
The best option for replacing your coffee grinder is to get a standalone electronic burr mill. This will give you a much better grind than a cheaper blade-based grinder and they aren’t much more expensive.
Summary
To sum up, you can easily adjust most grinders with a simple dial or rotating ring that is present either on the top or on the bottom of the grinder. Turn clockwise for finer grounds and anticlockwise for coarser grounds.
Having the correct grind size impacts the extraction process and flavor of your coffee, so it’s an important part of the brewing process.
If you can’t get your grinder to produce uniform grounds even after adjusting, it might be time to pick up a new grinder. A standalone grinder from Amazon is a great inexpensive option.