Time Your Coffee Grind

Timing is everything… and the timing of when you grind your coffee beans matters. I’ve briefly mentioned it before, but there is a huge difference in the taste of brewed coffee when you brew within 60 seconds of grinding vs. brewing coffee with beans you ground the night before while setting up the coffee machine before bed (or worse, preground coffee). Here’s why…

The thing that makes coffee taste so good are the coffee oils found inside the coffee beans. During the coffee roasting process, sugars are caramelized and oils are formed and trapped inside the bean, encapsulated and protected from the outside world for a very short period of time. These coffee oils are essentially what gives brewed coffee its great taste.

In a perfect world, these oils would just hang out inside the bean indefinitely, but there are 2 forces working against these oils: carbon dioxide and oxygen. These two goons have a special assignment: destroy the coffee oils within 10 days, and if we let them, they’ll do just that – every time.

Let’s take carbon dioxide. One result of the coffee roasting process is that carbon dioxide is emitted from a freshly roasted coffee bean for about 2 weeks. The CO2 is the result of the volatile roasting process… think of it like a Pepsi can shaken up. It takes a little while for the Pepsi to normalize and the pressure to subside. Same thing with fresh roasted coffee – the coffee bean is in a volatile state and over the course of 10 days or so, the carbon dioxide slowly pushes the trapped coffee oils hiding inside the bean out to the surface, the oils escaping through cracks and crevices found throughout the interior and surface of the bean. The cracks are too small for oxygen to enter, so the carbon dioxide does the dirty work by forcing the oils out.

Now that the coffee oils are exposed on the surface of the bean, the second force – oxygen – takes over by attacking the oils and in a very small amount of time (30-60 minutes) the oils become rancid and if the beans are used, the resulting coffee will taste very stale and bitter.

With that background, it’s easy to see how ground coffee creates so much more surface area for oxygen to come in and do its thing. And not only do you have 30-60 minutes to brew your coffee after grinding, but 80% of any carbon dioxide left inside the coffee beans dissipate into the atmosphere within 60 seconds of grinding! CO2 is the main transport mechanism for pushing out any oils inside the bean casing into the water when we brew, so we really need to do what we can (brew quickly after grinding!) to use it to our advantage to get those oils out.

Try brewing within 60 seconds of grinding your coffee beans and I bet you’ll make a better tasting cup of coffee. -Ken

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