Navy ship have to create their own drinking water. Using Reverse Osmosis, the ships convert salty sea water into something drinkable. The process creates a more acidic soft water instead of the hard water used for making tea. The soft water brews tea faster, but alters the flavor typically achieve during the brew. All About Tea’s HMS Bulwark teabags as sent to the crew. They contain a Ceylon, Assam, and African blend, and are designed to work with soft water to create the best flavor.

Key Takeaways:

• Ships make their own water—they don’t carry tanks of water around the place—and they use a process called reverse osmosis; they have RO plants on board
• soft water is more acidic, and hard water more alkaline. It’s this that affects tea brewing.
• “Standing on the bridge at 3 o’clock in the morning during the middle watch, a cup of tea makes all the difference, and if it’s something that really tastes good—which, frankly, MOD-supplied tea doesn’t—it’s one of those little things that can make a huge difference.

“The end result is drinkable, but not necessarily the best for a brew.”

https://motherboard.vice.com/read/why-british-sailors-need-special-tea