Should You Freeze Your Coffee Beans?
Price is a common lament among coffee drinkers, with upscale roasters and chains charging upwards of five dollars for a single caffeine fix. Brewing your own coffee can cut down on the expense, but if you invest in high-quality coffee beans, you’ll want to ensure that their flavor and aroma last. A popular “life hack” is to put them in the freezer, but is this effective? To answer this question, let’s turn to science…
Really Cool Beans: Storing Coffee at Below-Freezing Temperatures
A 2019 article from the Wall Street Journal details the extreme lengths that baristas and coffee roasters alike will go in order to preserve their beans and blends, which — taking both quality and fair trade into account — can cost more than $100 per pound! Tactics include separating beans into smaller containers and sticking them in dry ice as well as keeping the beans in ice cream freezers and even cold-storage warehouses.
What’s the best way to store coffee beans?
Along with cost efficiency, the purported benefits of frozen coffee beans include:
- Preserving the flavors and aromas of fresh-picked beans
- Achieving a more even grind, and therefore, a better cup of coffee
- The opportunity to store rare and premium blends for longer periods of time (potentially years instead of weeks and months)
The Wall Street Journal article suggests that to see these benefits, you would need to go beyond just throwing the bag of coffee into your freezer. This is because frost could form in the bag, or odors from other food products could contaminate the coffee. For a successful freeze, you should use an airtight container that protects the beans against condensation and excess moisture.
Studying the Coffee Bean Conundrum on a Molecular Level
So, does freezing coffee beans actually offer any benefits? According to research from the College of Agricultural Sciences at Penn State University, it does — but only for certain varieties of beans. The research method used to make this claim, called headspace gas chromatography–mass spectroscopy, enabled the Penn State researcher to separate all of the different types of molecules in a coffee bean and identify which ones are responsible for the coffee’s aroma. Looking at the length of storage time, temperature, and type of roast, the researcher then measured the rate of loss for these special molecules.
The results of the headspace GC–MS analysis were used to set up a blind taste test among a few dozen coffee consumers, comparing beans of equal age stored at room temperature vs. freezing temperature. The results of both the chemical and panel analyses suggest that freezing coffee beans is beneficial to the aroma and taste of dark roast blends, while the difference is less noticeable in light roast beans.
The evidence suggests that you should, in fact, freeze your coffee beans (depending on the type of roast), as long as you use an airtight container. However, more research is needed to determine how freezing rates and humidity affect the process, as noted by a chemistry professor at the University of Oregon in the Wall Street Journal article. Perhaps, that’s a case for simulation?
- Check out these other food science topics on the COMSOL Blog:
- Learn more about research into freezing coffee beans from the following sources:
- COMSOL Now
- Fluid & Heat
- Structural & Acoustics
- Today in Science