The obsession with “roasting dates” has led a lot of home bean brewers to accidentally ruin their own coffee. If you grind your own the second they come off the roaster, you’re essentially drinking a cup full of trapped carbon dioxide, which creates a sour, metallic tang that hides the actual flavor. But if you wait too long, or leave that bag open on the counter, oxygen rushes in to strip away the volatile oils that give coffee its aroma, leaving you with a dull, bitter mess. So hopefully you aren’t relying on bags to keep your Joe as fresh as possible.
If you’re serious about coffee, using the recommended burr grinder for consistent extraction and the golden ratio to brew is a good start. Bean freshness is another element that’s always worth considering. It’s a fine line, but knowing the best time to grind and the best way to keep beans fresh will go a long way towards improving the resulting coffee.
At this point, you’d be forgiven for thinking you’ve covered all the bases. But for the truly obsessive — and if you’ve made it this far, you know who you are — I’ve called on an expert to guide us through the best bean practices.
Luciano Repetto, co-owner of the multi-generational, artisanal San Francisco coffee roaster Graffeo, talks us through everything there is to know about optimal grind timing and storage for maximum coffee bean freshness.
Can coffee beans be too fresh?
There’s a temptation to believe that the best coffee comes from beans still warm from roasting, but what is true for the bagel you’re having with your coffee isn’t necessarily true for the bean. There is, in fact, such a thing as beans that are too fresh.
“With a traditional drum roaster, you have to wait several days before grinding, at least,” says Repetto. “The beans need time to release some of their aromatics, which can be a bit too strong right after roasting.” Much like you need to give a steak a few moments off of the heat before slicing into it, freshly roasted coffee beans also need a moment to rest.
“Off-gassing” or “degassing” is the necessary phase in which roasted beans release carbon dioxide after the roast. Skipping ahead to grinding before the CO2 has been adequately released may result in an inconsistent extraction in the resulting coffee.
The roasting method, however, also plays a big part in the timing here. According to Repetto, who uses a fluid bed roaster rather than a typical drum roaster, “based on taste tests we’ve done, you don’t have to wait weeks or days,” he says. “With fluid bed roasting, the tremendous amount of air used in the process strips the beans of smoke and chaff. The result is a very clean taste that’s ready much sooner, within 24 hours.”
For best results, wherever you are, ask your local roaster what method they use for roasting, or for their recommendation on how long to wait before grinding.
Grinding beans at home
You don’t actually have to grind beans daily for the best results. Grinding the whole bag upon arrival for convenience surely isn’t recommended, but “grinding a few days at a time is fine,” says Repetto.
But he echoes a sentiment many coffee pros we’ve spoken to have emphasized. “It’s how fresh the beans are and when they were roasted,” he says, that makes the real difference in flavor. “Beans don’t stay fresh for very long.”
Keeping beans fresh: Should you freeze or refrigerate?
So then, how to preserve that freshness? Perhaps you picked up a nugget of intel somewhere that suggested you can put your coffee beans in the freezer. And you’re thinking that you can buy freshly roasted beans in bulk to save yourself a bit of coin in the long term. Unfortunately, you’re going to want to file that nugget under “not great advice.”
“We do not recommend freezing them,” says Repetto. The low temperature may help slow the loss of freshness, but unless you are diligent about regular freezer upkeep and cleaning, it is simply too volatile an environment to do any good. Ambient humidity and persistent aromas can contaminate coffee beans, rendering useless whatever preservation of aromatic compounds you thought you were achieving.
You do want to keep them at a lower temperature and in a more airtight container than the bag you purchased them in to preserve the oils responsible for flavor. “The goal is to protect the beans from moisture while keeping them at a cool, stable temperature,” says Repetto. “That’s what keeps the oils fresh and the flavor intact. You can slow the staleness by storing them in a sealed container, such as a good jar with a lid and refrigerating.”
A jar or vacuum-sealed packaging is recommended, as the paper bag the beans likely came in will not sufficiently keep out moisture in the refrigerator. While you can grind up to a few days’ worth of beans at a time, when you’re storing them in the refrigerator, “your beans should be stored whole until you’re ready to use them,” says Ripetto.
The bottom line with bean freshness
No matter when and how you grind your coffee beans, or how you store them, the single best thing you can do for your coffee routine is to buy them local, freshly roasted and often.
“I’ll say this with no equivocation,” says Ripetto, “if the coffee you purchase is already two or three weeks old, you can grind it all you want and it’s not going to get any better.”
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