Why Grind Fresh?

You may have heard before that you should grind your coffee fresh, which is totally true. You can retain a LOT more flavor if you grind right before use. However, it left me wondering what happens if you wait, and what specific things you lose when waiting for 15 minutes, 30 minutes, 45 minutes, or even an hour after grinding. So, we conducted a pseudo-scientific test on our most popular coffee; Brazil.
Feel free to try this at home, this is what you need:

• 5 equal size small cups
• A few soup spoons
• Timer
• Scale
• Filtered Water
• Kettle
• Fresh Coffee
• Grinder

The coffee we used was 5 days off roast. We measured out 12g of coffee, ground it at a medium-coarse grind every 15 minutes, and laid it out in trays. After the full hour, we smelled each coffee to analyze the fragrance; the smell of coffee before adding water. We started by smelling the coffee ground an hour earlier, and made our way up to the freshest. The freshest was more pronounced; smelling of cocoa, peanuts, and apples. We felt as though the older coffees lost some of the more delicate notes and settled more into the cocoa region. 

Without waiting too long, we added 185g of 203° water to each cup using two gooseneck kettles to ensure the coffee was saturated all at the same time. Of course, using two kettles aren’t necessary, but it does look a lot cooler. Keep that in mind. 

We waited for 5 minutes before we realized that our plan was to stop brewing after 4...then we broke the crust that formed at the top, now analyzing the aroma. At this point, it was still on par with what we found in the fragrance. We then cleared off the remaining foam into a separate cup, and waited an additional 10 minutes before we started to taste. This gave us time to prepare our minds to be blown…also for the coffee to cool down and for the grounds to sink to the bottom.

We started tasting oldest to freshest, building our way up. In order to truly tell the nuances of flavor, I drank some mineral water before and after each cup...or maybe I just really like Topo-Chico. Either way, the main thing I noticed was that the biggest transition in flavor was between fresh ground and 15 minutes. While the fresh option was juicy and balanced, the 15 minute option tasted dry, bitter, and the acidity tasted sharper, and less specific. Each cup after that just tasted more and more like a cuppa from your local Motel 8.

Now, it’s not like it was terrible. I started off with good, fresh coffee. This test might have been even more evident with 2 week old coffee; which has more time to fully degass. Keep this in mind when grinding your coffee! Or, try this at home, and let us know what you found.