The Science Behind Freshly Ground Coffee
Since I first opened my eyes to coffee beyond Starbucks, I’ve been told that freshly ground coffee is better than pre-ground coffee. I didn’t know why, and I could never get a better answer than a pretentious scoff from the know-it-alls, yet I accepted their unquestionable logic and found that it is true: fresh is better.
However, maybe it’s due to an unresolved issue with authority (12 was a challenging year), or perhaps it’s my OCD (self-diagnosed), but I had to know why: why is freshly ground coffee better? Is it just personal taste? What does Science have to say about it? Am I just trying to fit in with all the “experts?”
The Degrading Process of Coffee
At the risk of sounding a little dramatic, you’re faced with a ticking timebomb as soon as you grind your beanbag. Your coffee is degrading before your eyes, losing both aroma and taste. The countdown starts as soon as the beans are roasted, but keeping them in their whole form will hold off the degradation a little longer.
Studies have shown that freshly ground coffee can lose up to 60% of its aroma after 15 minutes. Three factors contribute to this tragic degradation: oxidation, moisture, and CO2 depletion.
The Role of Oxidation in Degrading Coffee
The complex compounds within your coffee beans create your brew’s aroma and flavor. Not all these compounds are stable, meaning they can change quickly.
Through oxidation, a process by which compounds interact with air molecules to create different molecules, specific desirable flavors and aroma compounds are released from your coffee beans. When you grind your beans, you kick start this oxidation process, which is good if you brew right away, but not if you wait too long. Once those beans touch air, the oxygen zaps their flavor and immediately makes them smell different, causing coffee solubles to degrade or oxidize.
Oxidation is what gives your coffee its unique (depending on the roast) flavors and aromas, but oxidation will carry on whether you are brewing or not. You are making the most of your coffee’s deliciousness by brewing with a fresh grind, not pre-ground coffee.
The Impact of Moisture on Coffee
Here is something you may not know: the oils in coffee beans are water-soluble. If a peculiar brand of sarcasm does not affect you (I don’t blame you, it’s terrible), that was a joke. Coffee oils are water-soluble (laugh now).
Water solubility is a great thing. Otherwise, our coffee wouldn’t taste or smell as good as it does. However, it doesn’t take an entire cup of boiling water to dissolve those precious oils because even the moisture in the air can dilute your beans.
So unless you live in the Sahara, exposing your delicate beans to your home’s AC-moderated atmosphere can sabotage their integrity, and grinding only worsens it. When you grind your beans, you create more surface area for moisture to dissolve those oils, which hastens the dilution.
If you want the best-tasting coffee, it’s clear that freshly ground coffee is the way to go. Invest in a good grinder and enjoy the full aromas and flavors your coffee beans offer.
Why Freshly Ground Coffee Is Better: A Consumer’s Guide
1. Preserving Flavor and Aroma
Alright, so this point is pretty similar to the previous one. One CO2 is the primary 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 scratching only worsens it, which is good if you are brewing right away (like you should).
If you aren’t careful, improperly storing your beans can cause them to lose most of their CO2 (source) quickly, and grinding only makes this more complicated. If you let your grounds sit for hours or days, you waste the one mechanism responsible for your coffee’s great flavor.
Besides those three (excellent) reasons to grind only right before brewing, there are also two others to consider.
2. Avoiding Contaminating Odors
Here is a scary thought: all those other odors floating around your kitchen slowly infect your ground coffee, especially that onion you just finished cutting. If the idea of onion-flavored coffee frightens you (chills down my spine), don’t buy pre-ground coffee beans.
And if you think your grounds are safe in the fridge, guess again. Although the cold might neutralize your sense of smell, there are still plenty of odors around your refrigerator that you don’t want to settle into your grounds.
3. Controlling the Brewing Process
Brewing great coffee is all about control. You are Lenin, and coffee is your USSR. The more power you have over each aspect of the brewing process, the better shot you have of making exceptional coffee. Just don’t be a Stalin.
When you grind your beans, you have greater authority over grind size, which significantly impacts flavor. Most methods of coffee brewing, like espresso, pour-over, and AeroPress, require different grind sizes, but buying pre-ground coffee limits you to only one.
Choosing to grind your beans puts another step between you and your beloved coffee, but even if you only brew with one method, having the ability to change your grind size slightly can substantially impact the quality of your coffee. To find yourself a great grinder, click here for my list of 2021’s best hand options.
The Science of Freshness
Unlike the stoic snob behind the counter at the instantly Instagrammable coffee house, Science has opened its mouth and shared some knowledge bombs. Like most food items, fresh is better, and coffee is no exception – especially during coffee cupping sessions.
These flavor-packed little stimulants are sensitive and will only relinquish their best if appropriately handled. Whereas pre-ground coffee has already lost most of its delicate aromas and oils, freshly ground coffee beans are ripe for brewing. So yes, if you haven’t guessed yet, you’ll need an excellent burr coffee grinder to help with this.
Let me know your thoughts in the comments below, and if any of your friends ask you, “Why is freshly ground coffee better?” then send them this article. Also, check the article ‘Does coffee go bad?’ and never worry about a stale and bitter brew again.
FAQs – Freshly Ground Coffee
Why should I grind my coffee?
You should grind your coffee to ensure it gets all the aroma and flavor you’re paying for. Whole beans can last for about a month with careful storage; ground coffee begins to deteriorate in 30 minutes or less – good if you’re having pizza delivered, not so much if you’re keeping ground coffee in your kitchen.
Why is ground coffee cheaper than beans?
Ground coffee is typically cheaper than whole beans because it uses less expensive coffee beans that are roasted and ground at a lower price point.
The coffee beans sold as whole beans, mainly from specialty coffee roasters, are usually sourced from better producers, often single-origin farmers, and represent a higher quality product. When it comes to coffee, there are things to save money on and things to save money for, and whole beans fall into the latter category.
How do you keep ground coffee fresh?
Keeping ground coffee fresh is challenging. It begins to deteriorate after about half an hour.
If you need to keep ground coffee, such as when traveling without a grinder, pack it in an airtight container and store it away from light and heat. However, even with proper storage, ground coffee gradually loses its flavor daily. Once you experience genuinely fresh coffee, you’ll realize the difference.
Is ground coffee the same as instant coffee?
No, ground coffee and instant coffee are not the same. They differ in taste, quality, and strength.
Although they may look similar, instant coffee is produced differently and offers a distinct flavor profile. To experience the difference, try some high-quality instant coffee and compare it to ground coffee. Check out our recommendations for the best instant coffee and learn more about the differences between instant and ground coffee.