Perishability of coffee varies widely! It varies between roast degree, roasting methods, and roasting equipment.
The two major types of roasting are air roasting (convective) and drum roasting (conductive). Coffee goes stale as it oxidizes, and oxidation is aided when bean structure is damaged during the roasting process. Conductive roasting is more damaging to the beans, because direct contact with hot metal walls damage and deform the beans, making it easier for them to oxidize and go stale.
A lot of drum coffee roasters are more conductive, and they tend to damage the bean more. They cause the cellulosic structure of the seed to open up more during roasting, making the coffee ready to drink sooner (~48hrs), but also drastically shortening its shelf life to sometimes as little as 7 days. This is why there is so much controversy and misunderstanding about freshness in coffee.
I roast on a Probat P5/2. While it is technically a drum roaster, Probat is known for adding a lot of convective heat in their roaster. They get this done with proprietary paddle technology inside the drum that kick the beans constantly into the air. The result is a hybrid convective/conductive roast with a lot of characteristic of air-roasting.
I've learned over time that this hybrid roasting technology, in combination with state-of-the-art roasting techniques by Scott Rao, produces coffee with a very long shelf-life.
Our light- and medium-roast coffees typically need to sit at least 4-7 days before they have off-gassed and rested enough to be delicious. All our coffees are stored in air-tight bins that allow the one-way exit of co2. This removes any oxygen from the container and provides a long shelf life of up to 6 weeks before we start to notice any loss of freshness.
Our dark roasts are an exception, they typically become ready 48 hours post roast and should be consumed within 3-4 weeks for maximum freshness.
Our bag is designed to accommodate off-gassing while remaining air-tight. If your bag puffs up a bit (with co2), just give it a little squeeze to let it release from the on-way valve.
We taste test every single batch that goes out to customers, and we re-test passed coffees every 2 weeks. Although they typically sell faster than that. As such, we are always getting surprised by 4 and 5 week old coffees that taste as fresh as they did 7-10 days off roast, and in many cases the age makes them even better.
So, I'll leave you with a few tl;dr notes:
-The Specialty Coffee Association, in their stalling study, said properly stored coffee beans get better until day 21 post-roast. then they plateau in freshness, i.e. peak in flavor for 7 days before they start to fade in freshness gradually during week 5, and then precipitously lose freshness during week 6 and beyond.
-Our coffee is meant to be stable at room temp for about a month after you receive it. If you plan to keep it longer, please freeze it.
-ON FREEZING: Do not take your coffee in and out of the freezer for daily brewing. This causes condensation and unwanted moisture. If you like to freeze your coffee I recommend taking out of the freezer 2 weeks' worth at a time, and then storing that at room temp as you brew it.
-If you use your own storage option, we recommend something air-tight, that doesn't allow light in. They make really cool coffee storage canisters (my favorite being the Airscape) with a plunger as a lid that sits down on top of the coffee to achieve these goals.
-When you buy from subterra, you will be receiving coffee that is no more than 2 weeks off-roast, and its freshness is guaranteed for another 3 weeks after you receive it.
-If for some reason your coffee isn't perfect, PLEASE hit me up at will@subterracoffee.com and take advantage of our 100% satisfaction guarantee. Seriously, nobody does this!
I hope this covers some questions about freshness and perishability! Don't hesitate to reach out to me for further clarification on anything! -Will