Here’s Why Your Pre-Ground Coffee Is A Big NO-NO

A window into the world of coffee grinding

Two coffee grinders
Electric vs manual

Oxidation

Oxygen is coffee’s nemesis. Let me explain — once coffee is roasted it immediately starts to react with oxygen in the air causing it to lose flavour quite rapidly. Roasted beans, even when stored well (away from air and sunlight) should ideally be consumed within two months and actually taste best around 1 – 4 weeks after roasting, depending on how you plan to brew it.

… just 15 seconds after its ground, coffee starts to lose flavour and aromatics and within just a few hours there’s a significant and very noticeable drop in the quality of the cup.

If coffee, even in the bean form, is so easily affected by exposure to air, then you don’t need to try too hard to imagine how rapid the degradation would be if the exposed surface area was increased exponentially. That’s exactly what grinding does. To really drive this point home, know that just 15 seconds after it’s ground, coffee starts to lose flavour and aromatics, and within just a few hours there’s a significant, and very noticeable drop in the quality of the cup. In a nutshell, stop buying pre-ground coffee, buy smaller quantities of freshly roasted beans and grind right before you brew. Try it, I guarantee it’ll blow your mind! But, the only way to be able to do this is to have your own grinder. Not just any grinder, though, but specifically one with burrs and not blades. Let me explain why.

Coffee brewing workshop

A sealed coffee bag greatly reduces oxidation

Burrs vs blades

The lower the variation in particle size in ground coffee, the more evenly it will be extracted. If you want to dive deeper into why this is, follow this excellent thread over at Home-Barista. Blade grinders use varying speeds to chop the beans and this leads to two major issues — One, there’s no way to control the size of the resulting particles so having this vast spectrum of sizes results in very uneven extraction. Two, it generates a fair amount of heat, causing the coffee to release its tasty flavours into the air instead of being dissolved in hot water and brewed into your cup. Burr grinders are precision tools that push the coffee beans through two, revolving, abrasive surfaces separated by a distance that is set by the user to achieve the desired particle size. This level of control is what makes burr grinders far more suited to grind coffee than regular blades.

Coffee brewing workshop

Burrs vs blades

Electric vs manual

Now that we’ve covered why grinding fresh is so important and why burrs are better than blades, we can now look at the two broad choices that exist in the world of coffee grinders — electric and manual (hand). The two are quite different and have their own set of advantages:

Electric Grinders

  • Minimum effort
  • Quicker to grind
  • Larger hopper

Hand Grinders

  • Very portable
  • Far superior grind quality when compared to electric grinders at the same price point as they don’t require any motor or other electronic components
  • Allows you to immerse yourself more into the coffee brewing process
  • Typically offer a wide grind range all the way from Turkish to French Press
  • Quieter

If you haven’t already then check out 5 Hand Grinder Tips.

Coffee brewing workshop

Burrs of a Comandante hand grinder

Brewing Method

Another thing to factor in when you’re in the market for a coffee grinder is how you brew your coffee. The particle size that is required to brew an espresso is far smaller than what you’d need for a V60 and a French press is even coarser still. Espressos are very sensitive to even minute changes in grind size and so, most decent espresso grinders will be built to perform better with finer grinder sizes and will also be equipped with micro/fine adjustments to be able to really dial in the grind size. These grinder may not be the best choice if you primarily drink pour overs. Grinders designed for pour overs will be optimised to perform better with medium to coarse grind sizes and won’t need the micro adjustments. So before you go out and spend your money, make sure you buy something that is designed to perform well for your brewing method of choice.

Coffee brewing workshop

A cornucopia of coffee brewing equipment

If you love coffee and enjoy brewing it yourself, hopefully this post helped explain how important a grinder is and why it’s more of a necessity rather than a luxury. So stop buying pre-ground coffee and do justice to your next bag of beans!

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