
Traditionally, spring water collected for tea always maintained a connection with the earth it was drawn from. The longer this connection with the earth is maintained, the more fresh the final tea. In the past, long, narrow, cylindrical earthenware containers were used to collect water from natural sources. These containers very much resemble antique milk cans in shape with small fluted openings on top and two eyelets on each side for which rope was strung to ease the sometimes long journey home with a heavy load of fresh water. These vessels were primarily unglazed or with just the outside glazed with full exposure of the clay to the water collected inside. This allowed for complete interaction between water and earth. This whole process brought the tea drinker closer to the earth, the water, and the nature world.
After making the trip home with this water, it was immediately emptied from its collecting jar and into a ceramic storage jar. To this day these collecting vessels are still used in Korea, sometimes if just to transport tap water to storage containers. Either way, the important connection between earth and tea is reestablished. The result is better tea.
Because water is always interacting with the storage vessel, the raw material of the vessel is important in the maturation of the water. Glass vessels are rather neutral and don't enhance the character of the water inside. However, they also don't negatively impact the water. With that said, if water sits in a glass storage container for long enough, its qi will gradually deplete.
Nowadays almost all water containers are made of some sort of plastic. The materials for plastic will leach into the water, negatively impacting the final product. The idea of storing water is to maintain its connection with the earth and with nature. Plastics leach a range of very unnatural chemicals into water thereby degrading its qi.
If you purchase mineral water in one of those clear plastic bottles, it may be BPA free but it will still interact with the plastics of the bottle. Checking the date the water was bottled will not only limit the exposure to the plastic but will also ensure that your water is fresh. Of course there is also the environmental consideration of the disposal of these plastic bottles.
If you do use the large blue 20 gallon jugs ensure that the water in them is fresh and consider using a old ceramic crock to dispense the water in them. This will at the very least start into motion the renaturing of the water, establishing its connection to the earth once more.
The best material for the storage container is of course, clay. Ideally the best clay would be that closest to the source of the water. This would ensure that the water's connection with the earth is maintained. If an earthenware water jar is from the same location as the water its effect is increased. If that water is used to brew local tea, its effect is once again compounded. However, most times the earth is simply not appropriate for making these vessels. If earthenware water jar is made of materials closest to where you live it also has benefits, because it will bring the imported water closer to harmony with that of the drinker- this should also be considered. If the vessel is older it will have a vibrant qi of its own, and will not only nurture the water faster but will do so more effectively.
Finally, the technique for drawing water from these water storage containers should be considered. How you draw the water will subtly impact the qi of the water. You should use gentle and graceful motions to draw the water from the storage vessel. This not only imparts the qualities of reverence for the water but also helps quite the mind for the tea session. Also it will not stir up the sediment which will settle at the bottom.
Water is usually skimmed from the top of the container. This water has had the most interaction with air and nature and because it floats on top it is imparted with the softest, lightest qi, the most yang. This water harmonizes best with lighter teas. If you wish to get a heavier water you should scoop deeper into the water storage jar, but not too deep as to stir up the sediment at the bottom. This heavier water will harmonize with the heavier teas. The tool you use to scoop the water should be bamboo such as a Japanese hishaku or a gourd such as a Korean pyo choo bak. These scoops ensure the connection with water is maintained, bamboo and gourds are also light in nature which harmonize with the water they scoop from the container. A wood scoop is also acceptable, metal should be avoided.
Most 20 gallon jugs drian (have a spout) from the bottom. To combat this place the kettle lower as to create a large stream, this adds movement and gives the water some lightness and vibrancy before boiling. Likewise, if water from the tap is used run the taps for a minute to encourage the elimination of stagnant flat water before filling up the kettle. This will ensure that the water at least has some vibrancy to it.
Most people don't consider the storage of water and how breathability and stagnancy impact the water used for tea. The breadth and quantity of the information above strikes at the importance of this often overlooked issue when preparing tea.
Peace