Does freezing actually preserve coffee beans well?

Freezing slows oxidation and metabolic activity in coffee beans, locking flavor compounds inside, so flavor can hold up for roughly two to three months in a frozen state. It is a practical option for large batches after roasting. Improper handling, however, brings moisture and odor transfer, so the method matters as much as the temperature.

Frozen beans sit in a pseudo-fresh state, close to but not equal to the flavor a few days after roasting. Freshly roasted beans taste ideal from 4 to 30 days after roasting, once they have released carbon dioxide and shed the smoky, pungent edge of the roast. For daily storage, match the method to how soon the beans will be used.

How to properly store coffee beans after buying them home is a topic frequently discussed among many enthusiasts. Some people are used to putting the beans in the refrigerator, while others worry that moisture might instead affect the quality. After noticing this issue in the chat group, Front Street specially sorted out the principles behind frozen storage and the applicable conditions. Freezing can indeed slow oxidation and lock in flavor, but improper handling can also bring problems such as moisture and odor transfer. This article will explain the purpose of freezing coffee beans, its impact on grinding results, the hardware conditions that need to be met, and more practical ways to store coffee beans in daily life, so that you can also keep your beans in good condition at home.

"Front Street recently noticed a topic in the chat group"

How do you all store coffee beans after buying them? Put them in the refrigerator! I've seen many coffee experts put their beans in the refrigerator. But won't the beans get damp in the refrigerator? The refrigerator is dry! (So Front Street interviewed all the major coffee beans 🎤)

First, we need to understand why coffee beans are frozen.

What is the purpose of freezing coffee beans?

The purpose of freezing coffee beans is to keep them fresh. Freezing for freshness preservation is often used by merchants after large-batch roasting to ensure the freshness of coffee beans. Freezing treatment can greatly reduce the oxidation and metabolic rate of coffee beans, and can effectively "lock" flavor compounds better inside the coffee beans. According to research, in a frozen state, coffee flavor can remain in good condition for 2-3 months. Although freezing can preserve coffee flavor, the beans are in a "pseudo-fresh" state. Even if the flavor is close, it is certainly not as good as the flavor a few days after fresh roasting.

(Schematic diagram)

Front Street often emphasizes the freshness of coffee beans. Freshly roasted coffee beans are at their best tasting period from 4 to 30 days after roasting is completed. Why is it after the 4th day following roasting? Freshly roasted coffee beans produce a large amount of carbon dioxide inside, and the smoke generated during roasting gives the coffee beans a smoky, pungent taste after roasting is completed.

During these 4 days, the coffee beans release carbon dioxide on their own through the one-way exhaust valve, and the carbon dioxide carries the smoky, pungent smell out with it. This period is what we often call the resting period. Of course, depending on the roast level and roasting approach, the resting time for coffee beans varies, and 4 days is the "minimum" resting time.

So why do coffee experts freeze coffee beans?

To improve the grinding quality of coffee beans, making the particles after grinding more uniform. Coffee beans in a frozen state become more brittle, and the oils in the coffee beans are also in a congealed state. Grinding at this time makes the coffee particles more uniform and reduces the production of overly coarse or overly fine particles.

(Note! This is in a frozen state, taken out and ground immediately. Once thawed, moisture will form on the surface of the coffee beans due to the temperature difference, which will not only affect grinding but also affect the flavor performance of the coffee.) Moreover, during brewing, the water temperature also needs to be adjusted because the temperature of the coffee grounds is lower than room temperature.

So can we also use this method during daily brewing to make coffee particles more uniform? Front Street thinks it is unnecessary. First, this frozen grinding requires a very quick operation. Because the temperature difference is too large, in many cases frozen beans begin to produce moisture in less than 1 minute after returning to room temperature.

Second, hardware is also an important factor. If you find in daily use that coffee beans are very uneven after grinding, it is recommended to replace them with a better-quality coffee grinder. If there is only an excessive amount of fines, it is recommended to buy a fines sifter and sift out the fines.

What conditions are needed for freezing coffee beans?

Freezing coffee beans is not as simple as everyone thinks. It is not enough to just put them in the refrigerator. After roasting, coffee beans are placed into portion bags, the gas inside the packaging is extracted, and then they are sealed, keeping the coffee beans in a vacuum state before being placed in a refrigerator at -18°C to -21°C for freezing. Once frozen coffee beans are thawed, they cannot be frozen a second time.

(Schematic diagram)

Front Street has heard that many enthusiasts like to put the original packaging into the refrigerator's fresh-keeping compartment. If opened coffee beans are not properly sealed, the "colorful" odors in the refrigerator like to run into the coffee bean bag, and coffee beans happen to be in a state of "accepting everything," absorbing it all. After such beans are ground and brewed, the taste can make you question life!

How should coffee beans be stored in daily life?

First, when buying coffee beans, try not to stockpile beans. Buy the next bag after finishing one bag. When storing coffee beans, choose a cool, dry place. High temperatures will accelerate the dissipation of the beans' flavor.

For storage, you can choose to keep them in the original packaging. The coffee bean packaging sold by Front Street all has a one-way exhaust valve, which can release gas inside the packaging while also blocking outside gas from entering, but remember to seal the zipper properly. Those who have the means can also buy vacuum-sealed jars for storing coffee beans.

The above content is compiled by CoffeeHunters, a coffee news website.