Vacuum sealing coffee keeps it fresh for an extended period of time, even a year past roast date.
Whether it’s a competition coffee or a bag acquired from travel, some coffees are so spectacular that you want to hold onto every bean. By vacuum sealing whole beans and storing them in the freezer, you can preserve your coffee for over a year without noticeable degradation to flavor.
What does Stale Coffee Taste Like?
Stale coffee tastes bland and dry, like cardboard. Usually a bag of stale coffee will lack aroma and smell papery. The best way to prevent your coffee from losing flavor is to preserve its freshness.
Keeping Roasted Coffee Beans Fresh
Vacuum sealing coffee works because it reduces coffee’s exposure to the four horsemen of coffee apocalypse:
While coffee naturally degrades over time (around 30 days post roast date), oxygen, moisture, light, and heat cause coffee to become stale quicker.
When coffee beans are left out in the air, molecules that are responsible for flowery aromas and fruity tasting notes quickly degrade because of oxidation.
Oxidation is a chemical reaction that occurs when molecules are exposed to oxygen, like the browning of an apple or rusting of a bridge.
Coffee is exposed to less oxygen when stored in a mylar bag or an airtight container, but vacuum sealers remove the oxygen out of its container, slowing down oxidation completely.
As in brewing, water dissolves the flavor compounds in coffee. Because water is naturally found in the air, coffee beans degrade faster in humid weather.
Vacuum sealed coffee prevents coffee from being exposed to moisture both in the air and in the kitchen.
When coffee is exposed to light, it undergoes a chemical reaction called photodegradation, which breaks down fats and proteins responsible for flavor.
By storing vacuum sealed coffee in the freezer, you can reduce the coffee’s exposure to light.
Like in roasting and brewing, heat breaks down fats and acids in coffee. Constant exposure to sunlight or warm surfaces negatively affects coffee, because it breaks down flavor compounds prior to brewing.
Like with food, by bringing temperatures down, refrigeration and freezing slows down the natural decay of coffee.
The Myth of Roast Dates
Many roasters and magazines will argue that coffee is best consumed fresh, or immediately after roasting. While it is good practice to avoid grocery store coffees that lack a roast date or have an expiration date in place of a roast date, roast dates should only be used as a guideline for coffee freshness.
Resting and Degassing Coffee
Carbon dioxide (CO2) is trapped in freshly roasted coffee, as a byproduct of the maillard reaction during roasting.
Over a 10 to 14 day period post-roast, the carbon dioxide is slowly released or degassed from the coffee bean. This period is also commonly referred to as the “rest” or “degassing” period and the conclusion of this period coincides with when coffees peak in flavor and aroma.
Coffees degrade past this period and generally go stale by 30-45 days post roast.
How to Vacuum Seal Coffee as a Roaster
As part of our coffee tasting community, we allow coffees to rest for 14 days post-roast before brewing. We brew and taste coffees between days 14 and 21, looking for maximum flavor and extraction. When we deem the coffee to be at its peak, we label, vacuum seal, and freeze the whole beans in food sealer bags.
Through this process, we’ve enjoyed anniversary geishas and pink bourbons that have been roasted over a year ago, at peak flavor. This process feels similar to storing wines in a temperature controlled environment, and we reserve it for coffees that are truly spectacular.
Tips and Equipment for Vacuum Seal Coffee
We like the Nesco Deluxe Vacuum sealer, because it can seal multiple bags of coffee at once, in 20 seconds or less. Moreover its LED lights blink during sealing and act as a nice progress indicator.
The only downsides of the Nesco are its short electrical cable (less than 2 feet) and its volume when sealing (loud).
Priced at around $100 USD at time of writing, we think it's a worthwhile investment for anyone storing coffees worth preserving.
When brewing vacuum sealed coffees, we like to allow the coffee to return to room temperature before grinding.
While Nolan Hirte from Proud Mary argues that freezing allows for a more consistent grind size (even going as far as to freeze beans in their hoppers before grinding), we’ve found that the colder beans require a higher water temperature to fully extract the coffee. Because we dial in our coffees prior to freezing, we prefer the consistency of our recipe over the marginal benefit of a more consistent grind.
“It feels like there is a slight reduction in the aromatics, but the character in the cup seems to be absolutely still there.”
If you’re storing coffees at home, be wary of protruding items in your freezer that might puncture the plastic or damage the seal of your frozen coffees. We recommend storing the vacuum sealed coffee samples in tupperware or a dedicated box to prevent any accidental exposure to moisture or aromas in your freezer.
Coffee peaks in flavor and aroma 10-14 days post roast.
Vacuum sealing protects coffees against oxygen, moisture, light and heat.
To preserve coffees in their most flavorful state, you should vacuum seal and freeze them.
We recommend the Nesco Deluxe and Huispark vacuum seal bags.