Now that winter is on our doorstep, we are thinking of ways to get through the chill. One of the best ways to not only survive the winter, but also to enjoy it is to get yourself a vacuum flask.
For those who want to know a thermos flask and a vacuum flask are same. They re also referred to as insulated bottles or flasks.
How Does a Vacuum Flask Work?
A thermal flask (thermos) consists of two insulated layers (inner and outer) and trapped between them is a layer of air or simply vacuum in some cases which keeps liquids hot by stopping the escape of heat through three layers of protection (inner, vacuum, outer) and keeps liquids cold by not letting heat from outside enter the container, this achieved via double wall stainless steel.
The vacuum flask was devised to preserve liquefied gases by preventing the transfer of heat from the surroundings to the liquid. The evacuated space between the walls (which are ordinarily glass or steel) is practically a non-conductor of heat; radiation is reduced to a minimum by silvering the glass or steel.
In case you were wondering, in 1892, Scottish scientist Sir James Dewar invented the vacuum flask. Through his work in cryogenics, he identified a need to keep a chemical placed in a flask at a stable temperature. To do this, Dewar placed a glass bottle in another larger glass bottle, and evacuated the air between the two bottle walls.
So, now vacuum flasks are one of the most versatile accessories for people who eat out of home and it is a fragile accessory that needs special treatments if we want to preserve it properly over time.
Maintenance Tips for Vacuum Flask?
Clean the vacuum flask with warm water and make sure you wash up the liquid before initial use.
- For the best results, make sure you pre-fill for 3 minutes, with either hot water for hot beverages and cold water for chilled beverages.
- Avoid using a microwave to pre-heat the flask
- Avoid overfilling the flask. Make sure there is some space to fit the stopper
- Rinse the bottle in warm water if you haven’t used the bottle for some time
- Avoid submerging bottle in water as it may get between the liner and bottle
- Avoid using chlorine bleach to clean the thermos as it can damage the steel weld
- Not suitable for the dishwasher.
Can you Put boiling Water in a Thermos?
You can safely put boiling water in a Thermos without any issues. You do need to be careful with glass lined Thermoses as the quick change in temperature can cause it to shatter, but stainless-steel Thermoses are fine. The boiling water will stay hot for 6-12 hours.
Some of the wide-neck flasks are perfect for soup.
How to Clean your Vacuum Flask
Wash, rinse and dry the vacuum flask before using it for the first time. Always empty the vacuum flask after use. Wash it by hand, adding bicarbonate of soda or washing-up liquid to the water. Use a bottle brush to make sure it is thoroughly clean inside.
You can also sterilise it if needed:
- Pour the vinegar or peroxide into the bottom of the thermos.
- Add the baking soda.
- Fill the remainder of the thermos with hot (the hotter the better) water.
- Let sit for several hours, like overnight. (Do not cap.)
- Dump the container and rinse thoroughly.
- Wipe out as much water as you can with the towel.
You can also use tea bags to clean your flask. Put a tea bag in the vacuum flask and add boiling water to it. Fill the bottle and leave this mixture in the vacuum bottle overnight. Throw away the mixture in the morning and the bottle will be spotlessly clean.
The Issue of Milk
A good tip to keep the contents of your flask longer, it to first rinse the flask with boiling water to heat up the large surface area. This will keep your warm drink warmer for longer. You can put milk into a thermos but it needs to be below 40ºF (4.4ºC) or above 140ºF (60ºC) otherwise harmful bacteria can grow causing your milk to spoil and become dangerous to drink. It’s difficult to monitor exact temperatures so companies advise against putting milk in altogether.
The most common reason for an exploding flask is when food or drink is left inside. After some time, bacteria will start to grow and produce gas.The higher the pressure, the likelier the lid and its contents will “explode” when you open it.
In addition to drying your flask thoroughly after washing, a good storage trick is to insert some kitchen paper inside before storing it. Crumple it a little, making a ball. It is also suggested not to close the lip, you can also store it next to the base of the vacuum flask.
Cleaning and maintaining the flasks in the right way to increase the durability of the product and also ensure that the bottle is germ-free.