Finding Common Ground
This is a quick guide to grinding coffee at home. I will try not to go too much in depth with it. So first, let's get some things out of the way - Yes, you should grind only what you will use. No, do not refrigerate your ground coffee. Coffee holds it's freshness best when you keep it whole bean and you only grind what you need when you need it. Leaving coffee in the hopper of your grinder is not recommended either. Coffee gets oily with time and sticks to your hopper affecting your burrs and preventing future coffees you put in it from staying fresh. Keep coffee that you use on a regular basis at room temperature and preferably in a air tight container (our bags are specifically designed for that wink wink...)
Now, we know that finding the right grind for your daily coffee can be hard and confusing with so much information out there. Here is a simple guide to get you by. I have tried many coffees from different countries with varying methods for distinct cultures. One thing I have learned is people's taste is unique, so keep in mind these are only rough suggestions to get you started. My best advise is to try it yourself and fine tune your recipes from the amount of coffee you use to the grind level, from the pouring technique to your water ratio. Believe it or not, all these factors can change your cup's flavor. Find what you like and stick to it. Good luck!
The Grinds
To make things simple, there are three main grinds. Coarse, Medium, and Fine. From these flow all the other levels and are variable depending on your grinder, the brewing method you will use and your desired tasting outcome (coffee geeks, correct me if I am wrong). Obviously, making sure you start with fresh, quality coffee beans will make a huge impact. Finessing your grind adjustments to each alternative factor will help you find the happy medium.
You need to know that grinders are all different, burrs are not made from the same mold and motors can have several specs. This will make the grinding levels differ from one brand to the other and sometimes from one model to the other. Varying brewing methods require different grind levels too. Some extract flavor better with a fine grind and others with a coarse grind. Some brew faster with a coarse setting and others with a fine setting. And finally and like I said before, it's all up to your personal preference. Sometimes we like to adjust for a long extraction time and sometimes we need to shorten it. Sometimes we are using a new paper filter and need to adjust for the slow flow or using a mesh filter and need to keep fine grinds from making our cup too cloudy.
Grinding is vital for a great cup of joe, but it will definitely be subjective in a home setting to make up for the taster's palate. It's the groundwork for your tasty cup. The key is to find the balance between extraction time and extraction volume to hit bingo.
COARSE
Coarse is the first grind level. Only "extra coarse" beats it and not by much. If there was something above these two you might as well use the whole bean.
Coarse is great for a French Press or anything mesh filter. You can use extra coarse for a low acidity Cold Brew or an old Percolator. They say cowboys, back in the days, would brew their coffee in their socks - I want to believe that if they even ground their coffee it was certainly coarse. The point is, this grind will help keep any particle from making it through a thick grade filter. It also creates a smaller surface area for hot water to extract flavor from therefore, makes it an ideal candidate for steeping or quick contact brewing methods.
Coarse is a very sensitive setting, watch out for too coarse grinds that make water flow to fast and make a vegetable, bright cup. You can notice this in light roasted acidic coffees. If the coffee is too acidic you can probably fix it by grinding finer and extracting longer.
MEDIUM
Here's the second grind level and by far the one you'll play with the most. In the spectrum, medium sits sandwiched in between (hence medium) on one side fine and on the other coarse. This allows it to combine and linger between high particle and small particles of coffee grounds.
Medium-coarse will allow you to regulate the extraction time in fine filter, high yield brewing methods, i.e. the Chemex. The fine grade paper filter of the Chemex is specially design for clean, brilliant flavor in the cup. This prevents easy flow when your coffee grind is too fine. The quick extraction but the slow filtration provides for a well aerated and balanced cup. If you can't tell my preference over this brewing method maybe I should be more obvious. Medium-fine is best for pour overs like a V60, kalita wave or bonmac. This brewers tend to have thicker grade filters since the yield is small. This allows the coffee to get enough air through the short extraction time. A "fine-ish" grind level allows you to control that extraction time to ensure that biggest surface area is provided for the hot water to penetrate and extract the flavor.
It is of utmost importance to mention that the medium grind setting is the commercial standard for pre-ground coffees you can purchase at the store. This is done so it is suited for automatic coffee makers like your average coffee brewing pot at home or your office.
FINE
Last but not least, fine. This is the last stop before hitting the espresso realm in your everyday home grinder. To be honest, I have very few experiences using a regular grinder for espresso. I will have to explain myself later.
Fine grinds can create high contact surface area which helps when the extraction time is short. This is preferable in methods that use small quantities of water and typically a mechanical extraction process like a Vacuum brewer or an Aeropress. In short, what this does it creates a fine layer that allows water at high pressure to extract the flavor upon contact. The difference between coarse and fine in the same scenario is that coarse coffee grounds would allow water to touch less coffee particles in the same amount of time.
Passed the fine setting you will hit extra fine which is mostly used for Turkish coffee - a barely filtered syrupy cup of black coffee. If you like slurping on slushy coffee, you'll dig this one.
Conclusion
I hope this guide helps you navigate through different brewing methods and the specific grind levels for each one. Remember your grind settings might vary from one grinder to another, so tuning to your palate is always the best way to pin point the perfect grind level. As you explore new brewing methods your grind adjustments will have change as well. Keep in mind the logical statement that coarser means quicker flow and finer means slower flow. If you think water is going to fast through the extraction process than grind finer and grind coarse if it is stalling.
Finding the balance between extraction time and extraction volume will guarantee the most of your cup of coffee in terms of flavor and quality. Short extraction times with high yields tend to taste watery and acidic. Long extraction times with low yield are syrupy and often bitter.
BONUS: The Espresso Realm
I'll have to write a whole different blog for this, but I will give you a brief introduction. Espresso is the method of preparation, the beverage and sometimes a grind level. The Specialty Coffee Association of America (SCAA) defines espresso as “a 25-35ml beverage prepared from 7-9 grams of coffee through which clean water of 195°- 205°F (92°-95°C) has been forced at 9-10 atmospheres of pressure, and where the grind of the coffee is such that the brewing ‘flow’ time is approximately 20-30 seconds.” To dial in your extraction such that it nails these parameters your grind need to be tuned meticulously. Other factors will come into play, but it will mostly rely on your grind.
And that's why espresso gets its own spectrum. The adjustments in this process are often so finicky that one tiny change in your grind level can alter the results in large proportions. But we will look at that some other time. For now, enjoy your coffee!