You have an expensive coffee machine, the right beans, and the perfect roast, but you’re still unable to achieve the desired coffeehouse flavour. This is because numerous factors affect the flavour of coffee. Yes, the aforementioned factors are significant, but so are the grind size, the water-to-coffee ratio, and the roast date. While it’s nearly impossible to pinpoint the missing ingredient without practise and experience, many home brewers overlook the process of grinding beans.
Most grounds are stored in airtight containers to prevent them from going stale, and coffee grounds only lose a limited amount of flavour during storage. However, as soon as the beans are ground, they begin to release flavours and oils that will not be present in the final brew (according to Coffee Bean). To preserve as much of the coffee beans’ original flavours as possible, avoid the following.
Too early grinding diminishes coffee’s flavour. Simple Home Coffee suggests that a simple way to comprehend this is to consider why coffee beans are ground in the first place. The grinding of beans creates a larger surface area for water to contact, which extracts the desired flavours. The same holds true for coffee that has been exposed to air. When there is a greater amount of exposed surface area, more of the coffee’s flavour and aroma can be extracted. The purpose of grinding coffee is to liberate all the flavours contained within the bean. Once they are exposed to air, however, they begin to oxidise, which is a fancy term for spoiling, and you have less to extract when you brew.
The simplest solution is to delay grinding until you are ready to brew. Always store your coffee, whether ground or not, in an airtight container in a cool, dark location (via National Coffee Association). Additionally, keep all caffeinated beverages out of the refrigerator and freezer, as they may absorb the flavours of other foods.