December 2023

Is Fresh Best?

Welcome to the Cog Blog. We’re busy Holiday-ifying our spaces, gifting, and stocking up – and likely you’re in the same boat. One thing we love so much about the cooler temps is getting that extra excuse to have another round of coffee. Name a better duo than “wintertime” and “cultivating comfort”.

Resting coffee: freshest isn’t always best. 

You just got your hands on a freshly roasted bag of specialty coffee. You’re told, “let it rest a little, the coffee needs to de-gas.” 

But… how long do you wait? When is too soon, or too late? How should you store while it “rests”? 

We’ll answer these questions in looking at the science “coffee resting,” so you can buy for yourself (and others) with confidence that you will get the best out of specialty coffee.

The act of roasting introduces CO2 into the beans. Pulling a bit from James Hoffman’s A Beginner’s Guide to Resting Coffee, the presence of CO2 means a mix of bad but interesting things:

  • The bad part of CO2 is it is highly volatile, which means if you brew within a day of roast, your extractions will be unpredictable. You can see these gases escaping whenever you’re doing the bloom stage of a pour over, for example.

  • This volatility is especially problematic when brewing espresso, as that volatility is amplified by the pressure in those systems

  • The interesting part is that roast levels affect the amount of CO2 in a bean. Lighter roasted beans will have less CO2 than darker roasts and they will age more slowly than their counterparts.

  • CO2 won’t impart any particular flavor to a coffee, but it will prevent water from extracting the flavors out of coffee that we want, according to Jonathan Gagne’s The Physics of Filter Coffee.

In summary, we want these gases to leave, as they produce creating volatile brewing and can even shield flavors being extracting. If anything in your life should have rest, it should be coffee.

Ok, so resting coffee makes it better.

Can you brew a dusty coffee bag that’s been shoved into a cupboard’s corner for a year? 

The Specialty Coffee Association (SCA), who maintains the standards on all things coffee related, has done some science-ing on this, and have even made a handbook specifically for this.

Data from that handbook that jumps out are the various aromas that age over time. In this graph, note that the bottom line, described as an undesirable “cooked potato aroma.” In other words, if you want delicious coffee, brew when this has reduced significantly.

Of course, after a couple of months, all these aromas will decline to the point that they become stale and uninteresting, and that old dusty coffee will taste like old dusty coffee.


Is the range then from one day off roast to a couple of months?

Let’s see what Scott Rao recommends: 

“Drink old coffee! Seriously… lighter roasts will taste best 3-5 weeks after roasting, yet the majority of customers seem to want to buy fresh coffee, and I’m betting most of them drink it well before its flavor peak. We frequently recommend customers “rest” our coffee for several weeks, but it’s not always practical to do so.”

At Cog, we don’t roast our coffees to narrow “light”, “medium”, or “dark” profiles –– rather, we roast each bean to what we think is most delicious version. We do skew towards the lighter end of roasts, so we recommend brewing Cog coffee anywhere from 1 to 4 weeks off roast.


Here are some best practice for storing coffee at home

  1. Keep the coffee airtight. If the bag can be resealed, then make sure it is kept that way. If the bag can’t be completely resealed, transfer the coffee to an airtight container, such as a plastic tub with a lid or one designed specially for storing coffee.

  2. Keep the coffee in a dark place. Light rapidly accelerates the staling of coffee, especially sunlight. If you keep your coffee in a clear container, place it inside a cardboard box.

  3. Don’t put it in the refrigerator. This is a common practice, but it does not extend the life of coffee, and you can get cross-contamination of aromas if you have something particularly fragrant in the refrigerator with the coffee.

  4. Keep it dry. If you can’t keep it in an airtight container, then at least avoid placing it in a humid environment.

  5. Lastly, if you need to store some coffee for a long period of time, place it in the freezer to slow down the staling process. It is important to package it in an airtight container. When you want to use the coffee, defrost it thoroughly, but be sure only to defrost the amount you are planning to use straight away.

Imports from the coffee community

Clearing the chaff.

Are there topics you’d like the Cog Blog to cover? Any issues in your personal brewing? We’re always happy to troubleshoot, whether 1-on-1 in email, or going wide in these blogs so that others may benefit. Send us any questions, concerns, suggestions, existential dilemmas, or anything in between, to contact@cogcoffee.com.

Still not enough Cog in your life?

Until next time,
Cognoscenti Coffee Roasters


Cog Coffee