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Thermos flask - The secret to keeping coffee fresh longer

Being a coffee lover but also a white-collar worker busy from 9 to 5 who cannot find a coffee shop nearby is a dilemma. Many have thus chosen to make their own coffee and store it in a thermos flask. But maintaining the taste properly is trickier than it may seem. We’re going to unveil four simple, yet effective hacks to solve the problem. 

Storing beans  in an air-tight container

Once coffee beans are roasted, they are immediately attacked by surroundings affecting the quality and life span. Oxygen is considered the main factor in coffee stalling, through a process known as oxidation. The longer the coffee grounds or beans being oxidized, the more unpleasing and stale our coffee will become.  


Therefore, it is advisable to keep the precious beans in a container with an airtight lid and store them in a dark and cool place to slow down the oxidation process and preserve the freshly roasted flavor. Despite the attractiveness of the coffee beans, it is better to avoid transparent jars as the light could taint the flavor.

Buy the right amount of coffee

The oxidation continues when we grind our beans. It is estimated that fine espresso grind has a total surface area, which exposes to air, nearly 11,000 times larger than that of a whole bean. Therefore, it is a good idea to purchase smaller amounts of freshly roasted coffee which is enough for one or two weeks and grind it right before brewing.



Another way, in case we don’t have time or a grinding machine, is to divide our pre-ground coffee into multiple small jars and remember to fill it to the brim. By doing such, we will minimize the chance of oxidation by letting the coffee be exposed to the environment whenever the lid is opened.

Keep clean the thermos flask for coffee

If we have spent hours online to find out the answer to the secret behind the freshness of thermos-stored coffee, the common answer would be the thermos cleanness. Over time, with a lack of appropriate cleaning, the oil and coffee residue starts to accumulate on the thermos’s inner surface. Oxidation doesn’t stop when coffee is brewed, and the oxidation of coffee oil is the main reason behind the highly unpleasant rancid taste of coffee. 

Pre-heating the thermos flask for coffee

The key factor for coffee as a beverage to maintain its taste for a long period of time is temperature retention. One way to boost the heat insulation capacity of the thermos is to preheat it. This simple step is often skipped, but it’s easy to do and worth it, especially on winter days. Just fill the thermos about two-third full of boiled water while our coffee is being brewed, put the lid on, then pour out the water and quickly add our hot coffee. It is ideal to pour it right into our thermos flask for coffee and fill it to the brim to avoid contact with air.

Should you have any questions, wish to share your ideas of vacuum flask, or request a quotation, please send us an email: to export@rangdong.com.vn.

Our website: vacuumflask.rangdong.com.vn.

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