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Giuseppe Leone

Let's talk about coffee storage.

If you’ve found your way to this blog, first off -- hi, hey, welcome! Second, you probably put a fair amount of thought and consideration into how you can enjoy great coffee all of the time, which just so happens to be something we think about a whole lot around here. (Also, can we be best friends?) In this query lie enough variables to make your head spin, but for the perfect cup at home, the importance of storage is key to unlocking coffee that tastes delicious for longer. 

Give me Freshness or Give me Death… or a Vacuum Canister

To understand the importance of storage is to understand that coffee has both a long and short shelf life. It’s long in that it doesn’t spoil in a traditional way (i.e. the soggy bag of greens at the back of our fridge). However its deliciousness is short-lived. Over time, coffee loses what makes it special in the first place. The flavors and aromas you experience in a high quality cup are primarily lost to oxidation, along with exposure to excessive heat, UV light, and moisture. Oxygen is the enemy.

In an ideal world, we would always be enjoying coffee freshly roasted, which, by the way, doesn’t mean right off the roaster. It means giving the beans a recommended one week off roast to release carbon dioxide buildup from roasting, also known as degassing. 

From there, you have a two to three week window where the coffee will be in its prime, tasting more lively and delicious than it ever will. 

With coffee subscriptions becoming more common, it’s more achievable to drink fresh coffee like this all the time. Especially when you don’t necessarily need a fancy canister or container. Our packaging is pretty damn good, arguably the best available: a triple poly foil composite bag with a one-way valve. That valve ensures that the aforementioned carbon dioxide from roasting is released while pesky oxygen doesn’t get in. We also highly recommend a vacuum canister, but really any airtight container will get the job done. Just make sure it’s cleaned with an inert smelling detergent. Coffee absorbs aroma!

Store your fresh coffee (one week off roast) in a vacuum canister or our 12oz bag with as much oxygen squeezed out of the valve as you can, and place in a cool, dry and dark place. Enjoy those exquisite beans within the month from roast. 

Alas, life often has other plans, so what do we do when we can’t get through our coffee in that time?

Chill it Down

It’s been commonly promoted by coffee experts and specialty coffee roasters that once opened, coffee should be placed in an airtight container and stored in a cool, dry, and dark place, away from the fridge and freezer. However, it wouldn’t be like us if we simply accepted the recommendations out there without challenging the status quo. 

In 2016, Chris Hendon, et al. published a study on Nature.com showing that somewhere between -2.2°F and 68°F there is a wider variation in grind particle size compared to grinding coffee at colder temperatures. Even though it was not known where in this temperature range grind particle distribution was truly affected, this led to the third wave cafes around the world experimenting with freezing coffee to compare the effects of a more even grind particle distribution. (Check out a couple articles on this trend here and here.)

In two experiments spanning over twelve weeks, we took Hendon's paper into consideration while testing the industry recommendations for storage.

Our goal is to provide you with our best recommendations for coffee storage and enjoyment. 

Our Wholesale Manager, Matt Brown, comes with more than eight years of experience around this topic. He was involved in multiple storage studies commissioned by Seven Miles Coffee Roasters in Sydney, Australia between 2011 and 2019. The following is what he, along with resident Q grader and former Director of Coffee David Wilson, did in their experiments. 

Experiment #1: Room Temp vs. Fridge & Freezer

In our first experiment, we wanted to test room temperature (ambient, approx. 68°F) storage vs. the fridge and freezer. We roasted our Naia Bombe Natural process Ethiopian coffee to our usual light/medium roast profile for drip. The coffee was put into Weber Workshops’ single dose bean cellars with one way valves, as soon as the coffee was cooled from the roaster. They rested at room temperature for seven days before being put into either the fridge, freezer or left out in a cool, dark and dry place. This was to replicate the process of purchasing a bag from one of our cafes. 

Three weeks later, we roasted the same coffee with the same roast curve before immediately storing in a bean cellar. We also repeated this at weeks four and five, in order to test if week old coffee was considerably different to coffee at four to six weeks old in their unique storage environments. 

We used our standard cupping practices to assess the coffee and conducted them blind to reduce bias. We tasted:

  • Coffee stored ambient for four, five and six weeks
  • Coffee stored ambient and roasted one week prior to weeks four, five and six
  • Coffee stored ambient for one week and stored in a commercial fridge for four, five and six weeks
  • Coffee stored ambient for one week and stored in a household freezer for four, five and six weeks

The fridge and freezer samples were ground cold, except for the week 4 freezer sample, which was brought to room temperature. Here are our results: 

Rating of coffee samples on a scale from 0 (poor) to 10 (highest quality) 

An interesting result occurred in week four vs the other weeks due to a mistake. Due to some bad timing, our freezer sample was brought to ambient temperature before grinding. This shows one result in favor of grinding coffee cold. 

The freezer samples for week five and six were noticeably the best, with the fridge at a close second. The week off roast was a close third – all delicious coffee. The only compromised product was the ambient storage. We weren’t happy with this product in any of our tests, confirming our recommendation to brew the coffee within one month from roast date if you’re storing it in a cool, dry and dark place. 

What we didn’t know from these results is if you opened a 12oz bag and put them back into the environment if the above was replicated. We also wanted to confirm our suspicion that bringing the coffee to ambient temperatures from the fridge and freezer were detrimental to the coffee. This led to our second test. 

Experiment #2: From Fridge and Freezer to Room Temp and Back Again

For this experiment, we used our Manuel Gomez Natural process coffee. We stored the coffee in an airtight, quart sized container at ambient temperature (approx. 68°F). We then placed individual doses of the same coffee from the same roast in Weber bean cellars, our standard 12oz packaging, as well as a Fellow Atmos vacuum canister, and stored those in the fridge. All coffees were put into their unique storage environments as soon as they were cooled to room temperature after roasting.

Again, we used our standard cupping practices to assess the coffee and conducted the tastings blind to reduce bias. We tasted:

  • The coffee in the bean cellars:
    • One was brought to room temperature before grinding (two hours at 68°F)
    • The other was ground straight from the fridge 
  • The coffee in the quart container, ground at its ambient temperature
  • The coffee in the 12oz bag, opened, ground cold and put back into the fridge, with as much air squeezed out of the bag as possible
  • The coffee in the vacuum canister was ground cold and re-vacuumed 

We tasted these coffees sporadically over a four-week period from roast date. Here’s what we found:

Rating of coffee samples on a scale from 0 (poor) to 10 (highest quality) 

As you can see the winner of this storage test is the Fellow Atmos vacuum canister! Our 12oz bag came in second, which is encouraging as we spend a lot of money on this to ensure flavor is preserved. This shows that removing oxygen from around the coffee is undeniably beneficial.

The ambient storage in the quart container gave us some interesting results. By Day 9, we picked up a flavor that wasn’t consistent with the other samples. We confirmed this as a taint on Day 12, but on Day 9 it was just a subtle and pleasant tropical fruit flavor. It turned out we had used a brand new quart container that wasn’t washed before the coffee was stored. You could smell this in the plastic, and the coffee absorbed that aroma right up! 

We saw the most inconsistent results with the Weber bean cellars. We’re not exactly sure why. Perhaps the silicon valves failed, or the rubber o-ring connecting the lid to the canister allowed moisture in from the fridge, because we certainly didn’t see this in Experiment #1. We feel the quart container, 12oz bag, and vacuum canister presented consistent results, none of those storage methods showed the swing in quality that we found with the Weber bean cellars.

So it’s confirmed: if you won’t get through your coffee immediately, put that 12oz bag or vacuum canister in the fridge or freezer. Grind it cold and by the cup as needed. Make sure you put the remaining coffee immediately back into the cold with as much oxygen removed as possible. 

What’s Next? 

We haven’t covered all bases in these two experiments. We would love for you, the reader and coffee enthusiast, to bring us more problems to solve and questions to answer in the world of coffee storage. What are some challenges you face in storing and crafting great cups of coffee at home? What are some variables we may have overlooked? 

Your suggestions would help bring us closer to the very thing we want most in this life: to fuel you with delicious coffee, anytime you want it and wherever life takes you.

Thanks for reading, and happy coffee drinking! 

Have a suggestion? Please email us at info@coffeebar.com. We can’t wait to hear from you!

By Matt Brown and Kristina Tuason

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