It’s a humbling moment when you realize how little you know about something you considered yourself an expert on. Especially when it’s not just new ideas you hadn’t kept up with, but things you have to relearn.
That happened for me a week ago when I got a proper grinder. I’ve been drinking coffee since I was 11 years old (CdM in a can and a Mr. Coffee), have owned and tried many different ways of brewing coffee, and generally can make coffee I like. (I’ve written about this before.)
I know the theory – why a burr grinder beats a blade grinder, why fresh beans matter, that brewing coffee is a combination of water temperature, grind size, and the time hot water is in contact with the ground coffee.
All of that came down around me when I made my first cup of coffee from La Pavoni.
So much focus is given to the brew method used – automatic drip, french press, moka pot, percolator (really?), espresso, pour over with small holes, pour over with big holes, pour over with many holes, Chemex… that we forget the grinder is a more important part of the journey from bean to cup.
Let’s start by running through the basics:
Ground coffee is brought into contact with hot water. Hot water pulls out from the coffee various oils and chemicals present in the bean. Then you filter the spent coffee grounds out of the brew, and voila – a cup of coffee. The trick is to pull out lots of the tasty flavors, and not so much of the less tasty flavors.
Now compare the two ends of the grind spectrum, espresso and french press. Espresso is made by pumping hot water at around 9 bar of pressure through a puck of coffee. The coffee is very finely ground, and as a result the contact time between water and coffee is very short – a shot of espresso should take 25-30 seconds to brew. By contrast, the coffee in a french press is much more coarsely ground and steeps in hot water for about 4 minutes. So – finer grind, less contact time; coarser grind, higher contact time.
This is important because – here’s the lightbulb going off – grind particle size is not uniform. Think about it – your grinder’s job is to crush a roasted bean into pieces. It’s not likely that the coffee bean will break into very exact pieces. What you actually get is a distribution of particle sizes, with most of them being in the range of what you want – but a not-insignificant amount of them being much smaller, known as “fines”. (Math geeks will recognize a “bimodal” distribution, with a major peak where you want it and a minor peak less defined and wider in the fine particle sizes.)
Now, why do fines matter: Remember that getting the good stuff and not the bad stuff out of coffee depends on marrying the water/coffee contact time with grind size. If the grind is too fine, then the resulting coffee will be bitter – it’s over extracted and pulled out the bad flavors. So, think back to our french press, with its large coarse coffee grounds. Except there’s also fines in there as well. And those fines make the final cup bitter.
And this is part of what makes a great grinder versus an okay one. An okay burr grinder will grind coffee as you need it, but will also have fines present. Better grinders grind more consistently.
So, meet my new best friend – the Baratza Vario-W. Fitted with metal burrs that were designed specifically to minimize fines (instead of the standard ceramic burrs).
This is not a small investment; it’s Baratza’s top of the line model, does weight-based grinding (so I don’t have to try and pre-measure), remembers different weight settings, and has something like 240 distinct grind size settings. However, it saves me having to separately weigh out the beans in the morning, or having to grind them by hand while water comes to a boil. And – this is the kicker – I’m making better coffee than I ever have with a great grinder and a $4 plastic Melitta pour over I bought at the grocery store. Mind: blown.
In the week running up to the Vario, I had a chance to try out Baratza’s entry model, the Encore. At $130, it’s not necessarily cheap either, but I highly recommend it before investing in different coffee pots. It grinds evenly, it grinds well, and it’s easy to use. The Encore was a major step over my hand-cranked grinder. The Vario is a noticeable but incremental step up from the Encore.
(Another time, we’ll talk about water quality and temperature. In a nutshell, optimal brewing is 195F-205F, and most automatic drip makers don’t do a good job of getting water there and keeping it there.)
Some extra reading:
- Here’s a link to particle size distribution analysis from home-barista.com
- Baratza Grinders – great grinders from a great company
- A post about the metal burrs in my Vario-W from David Walsh, coffee geek extraordinaire.
- Greenway Coffee, my
pushersource for great coffee and info.