Does Ground Coffee Lose Caffeine Over Time?

by Peter Taylor | Last Updated: 27 January 2021

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Does Ground Coffee Lose Caffeine Over Time?

If you make coffee regularly at home, you’ve probably found the beans and brewing style that make the perfect cup, and if you’re like the rest of us, you may be impatient to get your hands on that first cup.

To save some time between waking up and that first sip, you’ve started buying pre-ground coffee or maybe want to pre-grind your beans for the week. But now you’re wondering, does pre-grinding seep away that first jolt of caffeine?

Ground coffee does not lose caffeine over time, but pre-ground coffee does lose its freshness. To find the sweet spot between pre-ground beans and the freshness you love, grind limited amounts of coffee beans and protect the fresh grounds from exposure to air, major temperature changes, and light.

We’ve gathered tips on how to enjoy your caffeine boost throughout the day by properly storing pre-ground coffee to maximize its freshness and tips on limiting caffeine without having to sacrifice taste.

Coffee and Caffeine

The caffeine in coffee comes from the bean and is stable for up to 4 years, which is hopefully longer than most of us keep a bag of coffee. In addition to the type of bean, the amount of caffeine in your coffee can be affected by the roast, the volume of coffee you brew, and the brewing method you use.

Beans, Roast, and Brew

Coffee beans are the seeds of coffee cherries, which grow on coffee trees, predominantly from one of two coffee plant species: Arabica and Canephora, also called Robusta.

When coffee is harvested, the seeds are removed and cleaned, yielding “green” coffee beans, which are later roasted to extract moisture and concentrate flavors. Arabica is the most common coffee species and has 34.1–38.5 grams (1.2-1.4 oz) of caffeine per kilogram of dry beans. Robusta has almost double the caffeine with 68.6–81.6 grams (2.4-2.9 oz) per kilogram.

Based on the typical mix of beans and the amount of coffee used for each type of brew, the average amount of caffeine in an 8-ounce (237-g) cup of filtered coffee, regardless of the filtering method used, is approximately 95 mg. Cold-brew steeped 8 to 24 hours yields 102 -159 mg of caffeine per 8 ounces, and espresso shots deliver approximately 63 mg of caffeine per ounce.

Specialty coffee shops may use different beans, blends, and amounts of ground coffee, and their caffeine levels vary accordingly.

The Benefits of Caffeine

According to researcher Mary M. Sweeny at the Johns Hopkins University School of Medicine, caffeine is a commonly consumed psychoactive drug that positively impacts mood and alertness and may have other benefits, including improving memory, athletic performance, and possible protection against diseases such as Alzheimer’s, Parkinson’s, diabetes, and certain cancers.

The U.S. Food and Drug Administration recommends that adults intake a maximum of 400 mg of caffeine per day, which leaves plenty of room for a few good quality cups of coffee.

Ground Coffee

Coffee is ground to extract its aroma and flavor from the roasted bean to help you get the richest flavor from your beans.

While grinding won’t impact the amount of caffeine in your cup, the longer ground coffee sits unused, the more its quality and flavor fade.

When To Grind Coffee

Because brewing from pre-ground can diminish its flavor and aromas, the best time to grind your coffee is right before using it to the right size for the brewing method you will use.

If you have a coffee grinder, it’s best to buy whole beans and grind them just before you brew them. If you have been thinking about getting a coffee grinder, experts recommend electric burr grinders, such as this Baratza and Bodum models, with a range of settings to ensure you get the right grind.

If you’re looking for one with more bells and whistles, both this Breville model and Baratza are designed for home use and have been well-reviewed by baristas.

Storing Ground Coffee

Exposure to air is the main reason the flavors and quality of coffee deteriorate over time. Exposure to air allows the coffee to absorb moisture, which causes it to lose the aromas and oils brought to life during roasting. Exposing the grinds to heat accelerates these processes.

The finer coffee is ground, the more its surface area is exposed to air, and the faster it will deteriorate.

Coffee Storage Pointers

You can store ground coffee for up to three to five months at room temperature. To preserve its freshness, you should store it in an airtight container at room temperature, protected from moisture and heat.

Does Ground Coffee Lose Caffeine Over Time?

Vacuum sealing is an excellent way to preserve coffee’s flavor but not a realistic option for most. The next best thing may be vacuum-sealed canisters. You can choose among several options, such as this one from Planetary Design or FoodSaver, or this Coffee Gator canister with a CO2 release valve.

Alternatively, to store the ground coffee in its paper bag, after taking what you need, push the air out of the paper bag as you close it, secure it with a rubber band, and place it in a resealable plastic bag, pressing the air out of the plastic bag before sealing it.

The Freezer Debate

Whether you should store coffee in the freezer is a matter of ongoing debate that depends to some degree on how it is packaged. Vacuum-sealed ground coffee can last up to two years stored in the freezer but only a month if it is not.

According to the National Coffee Association, coffee will absorb moisture, odors, and tastes from other stored foods in the freezer. It also will degrade from condensation, which is moisture that forms when the coffee is taken out for use.

If you want to store ground coffee in the freezer without a vacuum seal, store it in a well-sealed container and minimize the time it is out of the freezer to prevent condensation from forming.

The refrigerator is the least recommended spot to store coffee because it will draw in the ambient moisture and flavors of other foods, accelerating the loss of freshness and taste.

Ways To Cut Down on Caffeine in Coffee

If you need to reduce your caffeine intake without giving coffee up altogether, you can take incremental steps, such as using pure Arabica beans, using a lower caffeine coffee, reducing the volume of coffee per cup, or changing the way you brew it.

Drinking decaffeinated coffee, with an average of approximately 2 mg per 8 ounces, can also help you reduce your caffeine load. Decaffeinated coffee has suffered from a bad reputation for being a poor quality substitute for full-strength coffee, but the naturally decaffeinated options available today may be changing things.

Several websites round up their lists of the best-decaffeinated coffees; to find the one you like best, you can start your search here or here.

Final Thoughts

Whether you want to make sure your morning cup is full-strength or find ways to cut back on caffeine, aged ground coffee isn’t the way to go.

For the best-brewed coffee, make sure to use good quality coffee, the right grind for your brew, and optimize storage of unused coffee to preserve its aromas and flavor.

If you’re looking to limit caffeine, think about ways to vary the volume of ground coffee you use, the roast, the type, and your serving size. With many varieties of beans, roasts, brew methods, and decaffeinated options, you shouldn’t have to sacrifice your cup’s quality.


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