The INSIDER Summary:
- Coffee only stays fresh for seven to 10 days after it's roasted.
- That's because it releases CO2, after which it begins to oxidize, causing the coffee to lose flavor and caffeine.
- Most coffee from large retailers sits in bags for at least a month.
- A good way to tell if you're drinking fresh coffee is to look for a layer of foam or crema.
Here's some bad news for those who enjoy a daily cup of coffee from chains like Starbucks or Dunkin' Donuts: That cup of coffee is most likely not fresh.
According to coffee expert and Roasting Plant co-founder, Thomas Hartocollis, the vast majority of large-scale coffee retailers don't supply their stores with fresh roasted coffee. Here's why.
Coffee only stays fresh for a short amount of time.
Hartocollis compares roasted coffee to wine. Just like a bottle of wine turns flat and loses flavor after a few days of being opened, so does coffee.
According to Hartocollis, roasted coffee stays fresh for seven to 10 days after being exposed to the elements. That's because during this time, roasted coffee goes through a natural process where it releases carbon dioxide.
Once it finishes releasing CO2, though, it starts absorbing oxygen. This causes the coffee to oxidize, which in turn ruins the flavor profile and decreases the caffeine content. And unfortunately, no Tupperware can stop this from happening.
It's expensive and difficult for large retailers to supply their stores with coffee that's truly fresh.
According to Hartocollis, most large retailers roast their coffee in central facilities, meaning they roast huge amounts of coffee at a time and then package that coffee and distribute it. This is more cost-effective than small-batch roasting.
In an effort to keep the coffee as fresh as possible, the retailers use bags with a small valve that prevents the coffee from oxidizing.
But Hartocollis says this method only goes so far. The valve on the bag allows CO2 gas to exit the bag while preventing O2 from entering, but this means that once you do open that bag you don't have the usual seven to 10 days of freshness to drink it.
Instead, oxygen is going to rush into the bag and immediately become absorbed. Hartocollis says that studies have shown that coffee that's been sitting in a bag for a month loses 70% of its flavor very rapidly after being opened.
He says this is why bags of coffee from large retailers won't say when the coffee was roasted, but they will have a "fresh flavor until" date.
Coffee retailers don't want consumers to know this![Coffee Shop]()
Not surprisingly, most large coffee retailers are reluctant to talk about whether or not their coffee is truly fresh. According to Hartocollis, smaller shops that roast in store — like Roasting Plant — aren't afraid to bring it up because their coffee is served within two to seven days of when it was roasted.
Plus, drinking stale coffee isn't harmful for you in any way. Yes, it has less caffeine and less flavor, but most people don't know the difference because that's all they drink.
Hartocollis says the best way to tell if the coffee you're drinking is fresh is to look for a layer of crema or foam. If the coffee you're getting is just a jet black liquid, Hartocollis says this is a telltale sign that your coffee is actually stale.
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