2025-03-13
Whether you're using a manual grinder or an electric one, the fundamental operation remains the same. Coffee grinders work by adjusting the burr gap to control the size of the coffee particles. The space between the burrs determines the grind size – a 300μm gap gives you 300μm grounds. The process of "dialing in" refers to finding the right grind size and dose for your specific brewing setup.
Most grinders just need a quick wipe-down. At their core, all coffee grinders – regardless of brand or model – operate by adjusting the burr gap to control particle size. The space between those burrs dictates what comes out: set a 300μm gap, get 300μm grounds. What we call 'dialing in' is really the process of marrying your grind size and dose to your specific brewing setup
Same grinder model: Coarse setting (←) | Fine setting (→)
Let me reiterate, adjusting the grind isn't just about tweaking the coarseness settings on your grinder. It's about finding the right coarseness combined with the right amount of coffee grounds to achieve the perfect extraction time and the ideal volume of coffee. Note that this fundamental theory applies to all types of coffee. Next, I'll discuss grinding adjustments from both manual brew and espresso perspectives. You can either watch the entire segment or just the part that's relevant to you.
*Part 1: Manual Brew Grinding Adjustment
I find manual brew grinding adjustment relatively straightforward. Regardless of the variety of grinders out there, the method to adjust coarseness is quite similar—turning the dial, where smaller numbers indicate a finer grind. Before adjusting, it's crucial to understand how the coarseness of the coffee grounds affects the flavor of our coffee, assuming all other parameters are set correctly. You can also conduct an experiment using the same coffee beans but with three different grind sizes: very coarse, very fine, and normal.
Very Fine Grind
Medium-Fine Grind
Coarse Grind
If the coffee grounds are too fine, the small particles allow water to extract the flavors too quickly, leading to bitterness and other undesirable flavors. Imagine eating fine sugar—it dissolves instantly.
If the coffee grounds are too coarse, the large particles make it difficult for water to extract the flavors from within, and the water flows through the gaps too quickly, resulting in a weak and bland coffee. Think of eating a lollipop—it takes a while to get to the flavor in the center.
Only the right coarseness allows for optimal extraction, bringing out the best flavors while.
minimizing the undesirable ones, resulting in a great cup of coffee. Let me emphasize another key concept: extraction rate, which is the percentage of coffee solids extracted from the grounds. The maximum extraction rate is around 30%, which includes both good and bad flavors. Generally, an extraction rate of 18-22% is considered ideal for a tasty cup. Lower than this range may result in under-extraction and sharp acidity, while higher may lead to over-extraction and unpleasant flavors. This is where the concept of the "Golden Cup" comes into play.
What is the ideal coarseness? Think of granulated sugar. If you're unsure about the size of sugar granules, you can purchase a particle comparison card for a rough estimate.
For a more precise measurement, consider using a sieve shaker, which isn't expensive—just a few dozen yuan. Aim for a 70%-75% pass rate on the sieve for the ideal coarseness, then slightly adjust coarser for manual brewing.
Once you're close to the right coarseness, brew a cup and adjust based on taste. If it's too acidic, go coarser; if it's too weak, go finer. For a cleaner, fresher flavor, go coarser; for a fuller, sweeter profile, go finer. At this stage, you can also adjust other variables like temperature, water quality, stirring intensity, or even change the filter and paper to alter the extraction speed. These aspects delve into extraction techniques, which we can discuss separately if there's an opportunity.
Another scenario is when the grind size looks right, but the brew has a muddy layer of fine particles on top. This might indicate an excess of fine particles from your grinder.
You just need to prepare a sieve like this.
Using a sieve to remove some of the finest particles can improve the situation.While some fine particles can enhance the coffee's body and flavor complexity, too many can have negative effects.
Part 2: Espresso Grinding Adjustment
When it comes to espresso grinding adjustment, our goal is not only to get the coarseness right but also to ensure the correct amount of coffee grounds. First, check the size of your portafilter basket. Recommendations often assume a standard 18g basket. If you're using a 51mm or 53mm home machine basket, the 18g guideline might not apply. Refer to your machine's manual or check the basket's edge or center for recommended doses.
Once you know the recommended dose, you can start adjusting the grind.
Aim for a grind slightly coarser than flour
Too delicate powder, pinch will become flaky;
Generally, the finer the grind, the longer it takes to grind the same amount of coffee. Some grinders have timed or single/double shot buttons, but these can be inaccurate after changing the grind setting or coffee beans, so it's best to use a scale.
When you're close to the right grind, start extracting. Without pre-infusion, aim to extract double the amount of liquid from the coffee grounds in about 25 seconds. If using pre-infusion, include that time in your total extraction time. For example, with an 18g basket, aim for 36g of liquid in 25 seconds, allowing for a 3-second or 3-gram variance.
Also, observe your machine's water flow rate when running without coffee. Some machines have longer plumbing, causing a delay in water flow, which should be included in your total extraction time. If your machine takes 3 seconds to start flowing, your total extraction time should be 28 seconds.
If your machine starts flowing immediately, time accordingly.
When operating the machine, it's essential to observe the flow rate and time. If the extraction completes in just 10 seconds, it indicates an excessively fast flow rate, suggesting that the grind size should be finer. Remember, after adjusting to a finer grind, it's necessary to discard about 10 grams of coffee grounds, as they might still be of the previous coarser grind. After discarding, proceed with the extraction; this ensures the grind size setting is more accurate. If the extraction finishes in 20 seconds, which is quite close to our target, avoid adjusting the grind size immediately. Instead, make slight adjustments to the dose of coffee, increasing by 0.2 grams at a time. This method will gradually bring you closer to the desired parameters. Conversely, if the flow rate is too slow, apply the same principle. If the discrepancy is significant, adjust the grind size, and remember to clear out some of the residual grounds from the previous setting. If the flow rate is only slightly off, fine-tune the dose of coffee. During this adjustment process, my recommendation is to alter only one variable at a time—either the dose or the grind size. If the parameters are not significantly off, prioritize adjusting the dose. Only adjust the grind size if the parameters are considerably off, and remember to clear the residual grounds after doing so. Developing this habit can make your grind adjustment more logical. Adjusting both parameters simultaneously does not necessarily lead to quicker results.
With the right parameters in place, pulling a decent espresso shot that scores around 70 to 80 points shouldn't be a problem, provided that the coffee beans are of good quality as well. Some might say, "Oh, I can't really tell the difference between good and bad espresso shots; they all taste quite intense to me." In that case, I'd suggest diluting it with water to lower the concentration and then tasting it. The principle is similar to that of pour-over coffee: is it too sour and under-extracted, or too bitter and over-extracted? If you still can't discern the differences, that's perfectly fine. Trust your initial instinct—if it tastes good to you, then it's good. As you continue to drink the same beans over time, practice will make perfect, and you'll become more familiar with the flavor profile of those beans. Gradually, you'll learn how to adjust the grind accordingly.
For beginners, start by adjusting the parameters within a reasonable range based on my earlier suggestions. Recently, many have asked me why the espresso in videos looks so dark and rich with crema, while theirs doesn't turn out the same. This usually indicates that your grind adjustment isn't quite right. Check the freshness of your beans, the roast level, the dose, the grind size, and the size of your portafilter basket. These adjustments should resolve the issue. If not, it might be time to consider a different coffee machine.
Here are some additional universal tips for adjusting your grind:
If you want the flavors of medium-light roast beans to stand out more in an Americano or a latte, try extracting less—around 30g of espresso from 18g of coffee grounds. If you're extracting less espresso, you might also want to use a slightly smaller cup to maintain the intensity of flavor.
When I make our Ethiopian Geisha SOE, I extract a bit less and use a smaller latte cup, which makes the flavors more pronounced.
Using a normal-sized cup is also fine; it pairs well with fresh milk and can taste quite sweet. This choice depends on your personal preference.
If your coffee tastes weak no matter what, first check if your extraction parameters are correct. If they are, consider whether your cup is too large or if the beans aren't roasted dark enough.
Regarding the beans, the fresher and darker the beans, the coarser you can grind them. Fresh, dark beans contain more gases, and grinding them too finely can cause them to expand too much upon contact with water, leading to a slow flow rate. Conversely, for lighter roasts or older beans, grind them finer to prevent the flow rate from being too fast.
That's all I have on the basics of adjusting your grind. If you have any more questions or want to share your experiences, feel free to discuss in the comments section.
Finding the right grind size is essential for brewing a great cup of coffee. With these tips, you’ll have all the tools needed to adjust your grind for the perfect extraction, whether you’re making pour-over coffee or espresso. Experiment, adjust, and don’t be afraid to fine-tune until you get that perfect shot or cup. And remember: If your coffee tastes good to you, it’s good!
