1, the capacity of a liter of military kettle is the accumulation of experience, because the maximum capacity that a kettle (except plastic water bag) can carry is one liter, which is not cost-effective, but it is too heavy and bulky to carry. Moreover, a liter of water can also meet a person's daily drinking water (excluding the water obtained from eating), and the army can also replenish water when marching. The capacity of 1 liter is the best balance between capacity and weight.
2. In theory, green tea can be put into a military kettle, but military kettles are generally made of aluminum. Putting green tea will have a metallic taste (the taste of tannic acid in tea and the smell of metal contact), and it is easy to have tea stains that are difficult to clean.
It depends on the specific types of other drinks.
That's the introduction of how many liters of military kettle is here.