Why is Medium Ground Coffee Everywhere?
Is medium ground coffee the best grind size for everyone? If not, why does commercial, off-the-shelf coffee always seem to come as medium ground?
To understand the answer to this, it would be helpful to know a little about how the grind size affects our coffee experience.
Extraction (or, getting what we want out of the bean and into the cup)
Water dissolves the flavours and the caffeine in coffee. So, to extract more we can do a few things:
- we can use more water and keep 'washing' the flavour and caffeine out of the beans
- we can leave the coffee in the water for longer
- we can use hotter water
- we can use higher pressures to extract faster (espresso - although more about the unexpected results of caffeine extraction from this a little later)
- we can increase the amount of coffee in contact with the water
- we can increase the area of the coffee in contact with the water by grinding finer.
As you can see, there are a lot of things that can influence how much extraction we are getting. But, here's the problem:
Not all flavours are good flavours, and the water will pull all of them out eventually.
We need to carefully measure our approach to extraction, depending upon the beans, the roast level and the brewing method we are using.
Find out more about Dark Roast Vs. Light Roast in this article.
Roast Level and Extraction
Typically, lighter roasted beans are harder to extract from and it's easy to UNDER extract - resulting in sour flavours. So, if using a filter brewer like a V60, lighter beans need a little more help. To do this, you might increase the water temperature and grind a little finer to up the level of extraction. Darker roasts are easier to extract and there is a danger of OVER extracting and getting into those nasty, bitter flavours.
You can think of the flavours of extraction going from sour to sweet/caramel/chocolate to bitter as you move from UNDER to IDEAL to OVER extraction. We are always trying to reach that magical zone somewhere in the middle.
Now, a lot of this will come down to your own personal preference, so a little experimentation will be required. Just know that, if it tastes a little too sour to you, you can adjust one of the factors above to increase your extraction and push the flavours into the magic zone.
What's The Best Grind Size?
With everything above in mind, here are some good starting values for popular brewing methods. These are just a starting point and you absolutely should adjust to taste for different beans and roast levels.
- Coarse Ground Coffee - Cafetière. This is an immersion brewing method where the grinds sit in the hot water for about 4 minutes. As explained above, more time in the water means more extraction. A finer grind would dramatically increase extraction and risk going OVER into the bitter zone. Also, the metal gauze used to filter out the grounds is also quite coarse. A fine grind will slip through and leave you with a sludge of bitter grit in your cup. Not a problem with paper filtered coffee.
- Medium Ground Coffee - Drip or Filter. This filtration set of brewing methods (like the V60, Chemex, etc.) has water flowing through the grounds. This reduces the contact time and also the extraction, so we can afford to grind a little finer. The paper filters will also be able to capture the smaller particles and leave you with a cleaner cup. As always, a lot of variables can be altered to move the flavour into the magic zone of nicely extracted: water temperature and grind size being the main ones. The amount of water you use compared to the amount of coffee will also have an impact. Play around and see what a difference it can make.
- Medium to Fine Ground Coffee - Stovetop/Aeropress. Aeropress is a hybrid case: it's both immersion and filter brewing. The use of pressure allows a finer grind as the water can be forced through the filter - reducing contact time - but the duration of immersion will also need to be reduced to avoid over extraction. A 2 minute immersion phase is plenty, but again, play around and find something that works for you and your coffee. Stovetop/Moka also uses pressure, but the metal filter will allow some grinds through if it it take too fine. The speed with which the brewing happens is much faster than filter, so we need a finer grind to get the extraction back to where we want it.
- Fine Ground Coffee - Espresso. The time that the hot, high pressure water is in contact with the coffee is very short (that was the whole point of inventing espresso in the first place). To get the levels of extraction that we want, we need to grind things fine.
With an espresso machine, you're pretty much fixed with a temperature and pressure and can't change them as easily. To alter your extraction, you can play around with the grind size and the weight of coffee you use as well as the weight of coffee you get out. Remember that more water means more extraction.
We hinted earlier that caffeine extraction acts in a surprising way. Well, many people expect that espresso contains the most caffeine. It's a strong tasting coffee after all. The thing is that caffeine takes longer to be extracted than the other flavours, and espresso is one of the fastest brewing methods. If you're after a higher caffeine content then something like a cafetière, Aeropress, or filter coffee would yield a stronger kick. Also, darker roasts are thought to contain more caffeine (or at least give it up easier).
More on that here: Dark Roast Vs. Light Roast.
Is Medium Ground Coffee The Best Option?
No. No it isn't. In order to simplify production and make things cheaper, supermarket brands only release a few different grind sizes. It doesn't allow you the option to tune your grind to the bean, your brewing method, and your taste either.
See more about the whole Arabica Vs. Robusta debate and 'Big Coffee' methods.
At Recent Beans, we will be more than happy to grind the coffee for you. Just let us know which brewing method you will be using, how you like your coffee, etc. and we can adjust things to your preferences. We know that one size does not fit all and are determined that everyone will get to experience a magical cup. Even if you really do prefer medium ground coffee, we can do that for you too.
Written for Recent Beans by Jack Sheard, Freelance Writer - JACKEDCONTENT.COM