I see this everywhere on websites and in cafes, like a golden rule, or some sort of market monopolization they have. But good coffee isn’t as simple as “fresh is best”. This may be a hang over from years ago when the NZ market was flooded with Australian roasted coffee. But I thought I would tell you a bit about freshness.
During the first 6-10 hours after roasting, the coffee may not be a true representative of how it will taste a few hours later, as there are many gasses being released which impact the cup flavour. Many roasters and coffee cuppers will wait a day before cupping coffee, to allow for this degassing and settling.
Beans will age faster the darker they have been roasted. Also, lighter roasts will last longer as less of the oils have been transferred from the cell structure of the bean to the surface – it is partly the oils on the surface of the bean which in time turn bad and give ‘off’ flavours.
For plunger and filter, what we call “soft brewing”, beans are good from day 2, and as the days progress, the flavours will develop. Some coffees come alive days after roasting but in general, around day 10 things will start going down hill.
Most of us drink espresso in cafes. Did you know you DON’T want fresh beans for espresso? 7 day old beans are great! Espresso coffee goes through a very different process to brew, part of which is emulsification, and requires different rules to soft brewing (espresso not being soft). Espresso coffee shouldn’t really be used before day 3, as it will taste tangy, give bubbly shots, and generally be annoying to work with for the Barista. We recommend day 3-9 as ideal for our espresso blends and roast profiles.
There are differing opinions about the “expiration date” of coffee, but I generally recommend a maximum of a week for retail shelf life. Coffee doesn’t really go off, like food, but more undesirable flavours become dominant. If you buy coffee from the supermarket, you may be aware of “roasted on” and “best before”, there is a big difference. Supermarkets inherently tend to retail aged product (especially coffee) – it might be over a month old before it reaches the shelf. The ‘best before’ date really tells you nothing, as it is often recommending 6 months as good shelf life. Sadly this is the main outlet where we should be seeing “freshly roasted coffee”. So when buying, look for “roasted on”, rather than “best before” and do the math.
Here is a little summary which is a good enough starting place:
“Babbie’s Rule” (how long before coffee goes stale):
15 seconds; to serve espresso
15 minutes; to brew ground coffee
15 days; to grind beans for brewing
15 months, to roast green beans
November 1st, 2012