lately i started to drink matcha tea, as an experiment instead of coffee, and i have read many descriptions about it.  I want to drink matcha tea to work, but i dont want to make it every time here,but instead to have it in a thermos.I have an 1L stainless still thermos and the quantity is quite enough for 3~4 cups of tea.  So, is it ok to make the tea in the morning and having it till the end of working day or this process is not good for the tea? Will it change the color of it also?  Regards 
If you are not allergic to citric acid you can use it as a substitute for lemon juice in canning.   Related  Can I use citric acid instead of lemon juice when canning? 