Why you should be grinding your own coffee beans, and how to best do it.
"One of the core truths we’ve stood by…for years is this: the grinder is the single most important tool for making great coffee at home. If you want to take your home coffee game to the next level, investing in a good grinder is the smartest move you can make."
—Coffeegeek.com
Why your grinder is important.
In the past I have talked quite a bit about why you should grind your own beans at home, and so far have only given you one reason, but it is the top-line reason, which is a fresher taste and less staling. If you're accustomed to buying your coffee pre ground, this is the biggest upgrade you can make to improve your coffee overall, whichever brewing method you use. Using freshly roasted beans, ground just before use, means that fewer volatiles are released, and oxygen has less time to work at staling the oils before you brew. Result? cleaner and crisper taste and no mustiness or fishy smells.
Which grinder?
there are two broad groups of machines used to grind your beans. The cheapest will be the electric blade mill, sometimes sold as a spice/nut grinder. These use fast-spinning blades to break the beans into smaller chunks. While they have the advantage of being cheap, they do not produce a controllable, hence consistent grind size. You're going to get a mix of 'boulders', the visibly bigger chunks of grounds, and a lot of 'fines', much smaller pieces which will add to acidity and sourness in the brew. Overall, your extractions will be erratic and not repeatable. This lack of control is one reason why few in the hobby recommend them, even as an entry point. You will not get the best out of good coffee, but if you're buying cheaper beans and only use an automatic electric brewer, it might just be enough. If you have one, upgrade to a buur grinder and keep this for spices and whatnot.
Burr grinders are really where it's at for quality coffee. These machines use pairs of precision-machined burr sets, rather like tiny millstones. They are almost always adjustable, enabling a range of grind sizes, and will help you get the best out of quality beans no matter what your brew method. they are generally going to be built to better standards than the blade grinders, and produce much more consistent results. They are more expensive, starting at around $30 for the cheapest hand grinders, ranging to hundreds or even thousands of dollars for the quality electric grinders. A good grinder is always a worthwhile investment, many people suggesting that you spend ⅔ of your equipment budget on the grinder alone. A recent entry to the handgrinder market is the KINgrinder brand, with an offering around the $30 mark. A friend of mine has one of these and is very happy with it. It is excellent for pourover, would probably go fine enough for a moka pot, but are not suited for espresso. A couple of years ago I spent $70 on my Timemore C2 hand grinder, and am very happy with it, and will be looking to upgrade that to the C3 for a more consistent grind as soon as I can. One day when i'm flush with money i may go for an electric burr grinder for those occasions when i need to make coffee for more than just me. For now, the two minutes I spend manually grinding is not an issue; in fact it is such a central part of my coffee ritual that I don't think of the minimal effort.
There is, however, a second reason, and while I have hinted at it from time to time, have never explained why. You see, each brew method requires different grind size, and the reason is hydrodynamics, the physics of fluid movement. During brewing, the coffee grounds and the water need to hang out just long enough to extract the best of flavour from the grounds. Too much extraction can lead to bitterness, too little to sourness. The various brewing methods require:
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Turkish coffee needs the finest grind, almost flour fineness. The grounds and boiling water are heated together in the ibrik pot to produce very strong, dense flavour. Because the water is in contact for such a short time, it needs the finer grind to extract as much flavour as possible in that time. Not every grinder can get to this standard though, as the finer you grind, the more oils are expressed from the beans, and many grinders will barf on the very finest grind sizes and produce a messy output. Some grinders will even grind to a halt.
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Espresso uses high pressure to force hot water through a dense cake of grounds, to quickly extract a small quantity of distinctive and very strong coffee. This means again that contact time between water and grounds requires as much coffee surface area to be exposed. Grind size is about that of table salt, enough that when you pinch the grounds, they keep the shape of your fingers.
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Pourover (and your automatic filter brewer and most gravity-fed filter systems) needs medium to medium-fine, which is visually similar to granulated sugar, with a slightly coarser texture than table salt. The particles should be uniform to allow for even extraction.
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Moka pot needs medium-fine grounds, which is finer than table salt but not as fine as espresso. The texture resembles that of sand, allowing for good pressure build-up during brewing. Don't tamp the grounds down, but do ensure that they're evenly distributed in the basket.
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The Aeropress generally requires medium to fine, typically medium for standard brewing, resembling table salt, but can be fine for espresso-style brews. The grind should be consistent to prevent clogging and ensure smooth extraction. Give the grounds a little shake in the brewer to settle them to an even bed before brewing.
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Infusion methods like the French press and cowboy coffee need the coarsest of all. This is quite chunky, sea salt size. The infusion method has the coffee and water together for quite a while, and the larger grains don't over-extract.
Varying the grind
There are going to be minor variations, depending on your own brew method and the coffee you choose. Darker roast styles generally benefit from being slightly coarser. Denser beans (very high-altitude and lighter roast styles may need slightly finer grinding. . The grind should always be consistent to prevent clogging and ensure smooth extraction. As with so any things in the coffee world, you are the best judge of how you need to tweak your grinder whenever you change beans.
Maintaining and cleaning your grinder
Cleaning your coffee grinder is essential for maintaining the quality of your coffee and ensuring the longevity of the grinder itself. If you have an electric grinder, unplug it before starting! For a blade grinder, remove any loose coffee grounds from the interior using a soft brush or cloth. To eradicate oils and odors, grind a small amount of uncooked rice or a slice of dry bread. This process helps clean the blades and remove residual coffee oils, which will stale and smell and taste bad. After grinding, discard the rice or bread and use the brush again to eliminate any remaining particles. Finally, wipe down the inside and outside of the grinder with a damp cloth, making sure no moisture gets into the electrical components before reassembling the grinder.
To clean a burr grinder, the process is slightly different. Disassemble the grinder by removing the hopper and burrs according to the manufacturer’s instructions. Use a soft brush to clean the burrs, ensuring you remove any coffee grounds and oils. Avoid using water on the burrs. If you have coffee grinder cleaning tablets, you can grind them as you would coffee to thoroughly clean the burrs. Afterward, wipe the hopper and the exterior of the grinder with a damp cloth, ensuring that no moisture enters the grinder. Once everything is dry, reassemble the grinder.
To maintain optimal performance, it’s advisable to clean your grinder every few weeks, or more frequently if you use it daily or switch between different types of coffee beans. Always avoid submerging the grinder in water or using excessive moisture, especially for electric models. Lastly, refer to the manufacturer’s guidelines for specific cleaning recommendations, as they may provide additional insights tailored to your particular grinder model. By following these steps, you can keep your coffee grinder clean and in good working condition, ensuring that every cup of coffee tastes fresh and flavourful.
Postscript
Oddly, when polishing this writeup i had a text from a friend who had just lost power, and said "wishing I had a hand grinder like yours"! Synchronicity strikes again.
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