How to preserve tea taste for 6-7 hours?

Question

I am new to this site and I hope my question is clear to everyone.

1. I prepare 4 cups of black tea in the morning by bringing water and tea powder to boiling.
2. Then I pour this into flask by filtering tea powder.
3. Whenever I feel like drinking tea, I pour black tea from flask, add sugar and milk and heat it for 1 minute in microwave.

I noticed that tea taste is changing from fresh prepared tea to 5 hours after.

Is there anyway to keep the same taste? I don't want to prepare tea every time I want to drink.

Answer 1

Have you considered investing in a good (read: expensive) insulated flask that is rated for 6+ hours and hot liquids? As long as you only open it long enough to pour your cup out, it should keep it at a drinkable temperature and (hopefully) not spoil the taste like reheating does.

If you do this, you should heat your milk separately so it doesn't cool down the poured tea.

Answer 2

Can you describe the taste? Black tea will usually go bitter after a few days.

Fresh tea and the lovely aromatics is very different than tea 5 hours later. Mech's comment about an insulated flask that can limit the air exchange should help.

If that doesn't work, you might try a reverse approach. Brew your black tea hot. Plunge the flask into ice cold water to stop the brewing. Keep the flask in the fridge or in a portable cooler with ice. When you go to make your hot tea with milk and sugar use the cold black tea from your air sealed chilled flask and microwave it for a little bit longer to get it to the desired temperature.