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How to Make Thermos Coffee?

There are many ways to brew coffee. Some of them, like pour-over coffee-making, are simple, while others require more skill.

These are the conventional methods of coffee making that we all know about. But there are others that few people are aware of. And making coffee in a thermos is one of them.

People have been brewing coffee in thermoses for ages. It’s just not widely recognized as a coffee brewing method.

It’s a quick way of making coffee when you don’t have a coffee making machine such as a French Press.


silver and black travel mug


Brewing coffee in a thermos is as simple as pouring coffee grounds into a thermos, filling it with hot water, and sealing it. While thermos coffee making is simple, some factors determine how good it tastes. These are


Factors to Consider When Making Thermos Coffee


brown coffee beans beside white ceramic mug


The Grind

The grounds you use to brew your coffee will determine its flavor. Fresh, coarsely ground coffee makes the best brew when preparing thermos coffee.

You can use coarse grounds to prepare cold brew during hot weather and a strong batch of coffee during cold weather. That’s because brewing thermos coffee gives you a chance to steeps grounds for a minimum of 3 hours, allowing them to release their flavor.

Brewing Time

The longer you brew thermos coffee, the more flavor you can expect from it. That’s why coarse coffee grounds are recommended because they need a long time to release their coffee flavors.

It’s best to brew thermos coffee at night before you head to bed. That will assure you of a hot, strong brew in the morning. You may also brew it before going to work and carry it to the office.

While you can brew Thermos coffee overnight, keeping it in the thermos for a whole day will ruin it. Therefore, drink it within 3 hours of opening the flask after brewing.

The Thermos

The quality of your thermos coffee will depend on the kind of flask you use. It should be a quality thermos that can keep your coffee hot for more than 12 hours.

Otherwise, a thermos that does not preserve heat will cut down on the coffee brewing process and result in weak, tepid coffee.

A good thermos for hot coffee is a stainless steel thermos. It should be made of food-grade stainless steel because it’s easy to clean and will not stain easily.

The state of your thermos will also determine the flavor of the thermos coffee you make. Therefore always clean your thermos thoroughly to get rid of any residue or odor. That way, you can brew your thermos coffee in a clean vessel that will not spoil the taste of your coffee.


Advantages of Making Thermos Coffee

  • It Saves Time

Once you know how to brew thermos coffee, you won’t have to wake up early to brew it every morning.

Leaving the coffee brewing in the thermos overnight means you can take your coffee first thing after waking up.You may also grab the thermos and have your coffee on the go while in the car.

Thermos coffee brewing is the perfect coffee making method for people that are always on the move.

  • Extracts All Flavors 

The longer you brew coffee grounds, the more flavor and caffeine you get from them.

While brewing coffee using a machine takes minutes, thermos coffee brewing is often done overnight. That gives the grounds enough time to release their flavors resulting in a flavorful, caffeine-rich beverage.

It’s the best way to brew coffee using coarse coffee grounds.


Disadvantages of Making Thermos Coffee

  • Loss of Aroma

Although thermos coffee making is an ingenious and simple way of brewing coffee, it does not preserve the flavor and taste of coffee.

Coffee loses its aroma within 20 minutes of brewing it. That’s due to the loss of a chemical called 2-furfurylthiol that decreases the more you have coffee in the thermos.

2-furfurylthiol is responsible for the aroma of freshly brewed coffee, which makes drinking it enjoyable. That aroma decreases by 50 percent within 20 minutes of preparing thermos coffee.

Therefore, if you leave your coffee to brew overnight, you can expect it to have no aroma. However, it will be hot and strong, which is what you need in the morning.


How to Make Thermos Coffee Overnight?


stainless steel vacuum flask beside brown cookies on brown wooden



2 Tbsp of Coarse coffee grounds

6 ounces of hot water

A flask


  1. Scoop coffee grounds into the thermos.
  2. Boil water to 95 degrees celsius and pour it into the thermos.
  3. Tightly close the thermos lid and leave it for a few hours or overnight.
  4. Gently flip the thermos upside down 3 -5 times before serving the coffee.
  5. Strain it into a warm coffee cup and add creamer or sweetener if preferred.


How to Make Thermos Coffee in Minutes?

It’s important to note that you do not have to brew your thermos coffee overnight. You may brew it for a few minutes in a travel mug.

Some great examples of travel mug coffee brewers are Bodum Travel Press, Soma Brew Bottle, and AnyCafé travel brewer.


A travel coffee brewing mug

1 Tbsp of medium grind coffee grounds

Hot water


  1. Scoop the coffee grounds into the filter basket that comes with it.
  2. Fill the coffee mug with water you’ve boiled to 96 degrees celsius.
  3. Tightly cover your travel coffee mug and wait for a few minutes.
  4. Twist the cap off your coffee brewing mug, throw the grounds out of your filter, and enjoy your coffee.
  5. Most travel coffee brewing mugs have a system that tells you when your coffee is safe enough to drink.
  6. For example, the Xterra coffee brewing mug has a color-changing band that tells you the right time to drink coffee.
  7. If your travel mug doesn’t have a temperature alert system, pour your coffee into a mug before drinking to avoid burning yourself.



Now you know how to make thermos coffee. It’s quite a simple coffee brewing method that you can use to prepare your morning coffee overnight. You may also use it to make coffee on the go.

The most important thing to have when brewing thermos coffee is a good quality coffee flask.

Try this coffee brewing method to make your next batch of coffee and see how it goes. It may free you from having to use coffee making machines.


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