Storing Ground Coffee for Maximum Freshness

In another article, we discussed the storage of coffee in general. In that article, we mainly focused on the storage of whole green beans and whole roasted beans, but touched only briefly on the storage of ground coffee. Because many people use pre-ground coffee – either purchased in vacuum-sealed cans, or ground at the supermarket - we thought it useful to devote an article to the proper storage of ground coffee.

It is rather interesting that so many people have used so much ground coffee for so many years, and there is no universally understood (i.e., known) method for the “best” storage of ground coffee. Many people don’t think about it at all (and they usually drink dried-out and/or stale coffee), and have merely become accustomed to the lackluster flavor of improperly stored coffee.

Ironically, many others take real pains to store their coffee in unusual ways (based on strange theories) that are also wrong, and that can damage the coffee just as much as taking no pains at all. We want to address a few fundamentals here, and then explain the best basic ways to store ground coffee.

It should come as no surprise that the main thing that damages ground coffee is prolonged exposure to air. This is why factory-ground coffee is vacuum-sealed. Air works to damage coffee via two different mechanisms.

The first is the absorbtion of moisture out of the air. The second is the loss of moisture into the air. And of course, high temperature accelerates both mechanisms. The best way to store ground coffee is to store it in ways that avoid both mechanisms (i.e., that hold coffee in “equilibrium”) and to avoid high temperatures. Simply freezing it is also a bad idea, if this is all that you do.

Vacuum Sealing & Freezing

By far, the best thing that you can do to keep ground coffee fresh is to vacuum-seal it. Vacuum sealing equipment is now inexpensive, and is available today in any department or appliance store. These vacuum sealers use FoodSaver bags (which are sold in rolls), and many of them also come with special canisters that you can use with them.

A good way to use these two types of containers is to vacuum pack the ground coffee in a FoodSaver bag if you are goingf to freeze it, and to use the FoodSaver canisters for pantry storage.

If you intend to freeze the coffee for longer-term storage, you may leave the coffee in its original packaging, and place multiple such packages into a FoodSaver bag. Vacuum seal it, leaving about an inch at the end of the bag to allow for opening and resealing of the bag. (Alternatively, you can pour the ground coffee out of its original packaging directly into a FoodSaver bag.) In either case, vacuum seal the bag, and then store it in the freezer.

If you do not intend to store the ground coffee for a very long time, then there is no reason to freeze it. Instead, to store the coffee in the pantry, pour it out of its original packaging into a FoodSaver Canister. Then vacuum seal the canister, it and store it in the pantry. Ideally, the pantry should be cool (at or below room temperature), and if the canister is clear, then the pantry should be dark.

As a “rule of thumb,” frozen ground coffee can last and keep its freshness for up to two years if the coffee has been vacuum-sealed, but not more than six months if it has not. And when not frozen (e.g., for in-pantry storage), vacuum-sealed coffee can keep its freshness for five to six months. But if the coffee has not been vacuum sealed, it will not keep fresh for more than a month.

So vacuum sealing will prolong the life of the coffee by a factor of 4-5X, and freezing it (after vacuum sealing it) will extend its lifetime by another factor of 4-5X. But it is not a good idea to freeze the coffee without vacuum sealing it first.

This is because moisture inside your freezer can permeate the coffee and crystallize, thereby imparting various freezer odors to the coffee when it is eventually used. Interestingly, when not vacuum sealing, whole roasted coffee beans will suffer from freezing more than ground coffee, because there will be more air (and hence, crystallization) in a package of whole coffee beans than in a package of tightly-packed ground coffee.

When you want to use coffee that you have vacuum-sealed and frozen, open the bag and remove only as much coffee as you will use in a week or so, then re-seal the bag, and return it to the freezer. Allow the coffee that you took out to come to room temperature before brewing it.

In general, you should not keep coffee (that is not vacuum-sealed, nor frozen) for more than 2-3 weeks. Only buy as much coffee as you are likely to use in that interval. If you buy more than that, you should really vacuum seal a portion of it for later use, and then freeze it. (Again, don’t merely freeze it without vacuum sealing it first.)

And when you are keeping coffee around for use within the 2-3 week period, you should keep it in an air-tight container at room temperature. Don’t refrigerate it. Again, at refrigerator temperatures, water molecules in the air within the canister will condense at these temperatures, and permeate the coffee.

The best material for an airtight container is ceramic or glass. Metal and plastic can impart strange flavors to the coffee, since they are both reactive materials. Ceramic and glass are not. And it is best to keep light away from the coffee, so a solid ceramic canister is better than a clear glass one.