There’s more to world of coffee then just Starbucks and Cafés! Home-brewed coffee is so much cheaper, and it tastes just as good, if not better. Doing things yourself is so much more satisfying isn’t it? You can tinker your grinds to your preference, according to the process you want; plunger, espresso, you name it.
But why does fresh ground coffee taste so good? Is it just my personal taste, or does science have something to say about it?
Well, science did have some interesting things to say and there were 3 contributions; oxidation, moisture and CO2 depletion.
Oxidation
The different compounds within coffee beans is creates your brews beautiful aroma and flavour. However, not all these compounds are considered stable, meaning they can change easily.
Through oxidation, a process by which compounds interact with oxygen to create different molecules, certain desirable flavour and aroma compounds are released from your coffee beans. When you grind your beans, you kick start this oxidation process, which is a good thing if you brew right away, but not if you wait too long. As soon as your beans touch air, the oxygen begins to zap their flavour, making them smell different almost immediately. It causes coffee solubles degrade and oxides.
This oxidation is what gives the coffee its unique aromas and tastes, but oxidation will happen whether or not you are brewing. So, brewing with a fresh grind, and not pre-ground coffee, you make the most of the coffees deliciousness. There’s a clock on your coffees tasty lifespan!
Moisture
Here is something you may not know: the oils in coffee beans are water soluble.
Water solubility is a great thing, otherwise the coffee we enjoy wouldn’t taste or smell as good as it does. But careful, because even the moisture in the air can dilute your beans.
Unless you live in the Sahara, the simple act of exposing your delicate beans to our New Zealand atmosphere can sabotage their integrity, and grinding only makes it worse. When you grind your beans, you create more surface area for moisture to dissolve those oils, and therefore hasten the dilution.
So once again, we are on clock for freshness!
CO2 Depletion
Alright, so this point is pretty similar to the previous, but in a reverse effect. CO2 is the main agent that transfers your coffee beans’ oils into your coffee, and when you grind your beans you create more surface area for the CO2 to escape. Coffee beans are already very porous, so grinding only makes it worse, which is a good thing if you are brewing right away (like you should).
If you aren’t careful, improperly storing your beans can cause them to quickly lose most of their CO2, and grinding only makes this harder. If you let your grounds sit for hours or days, you are essentially wasting the one mechanism responsible for your coffee’s great flavour.
