Water affects tea.
(Emphasizing this for those who are unfamiliar with the concept: Using good water is the single most important thing you can do to significantly improve your brew.)
More specifically, the mineral profile of your water affects the brewing process of tea, which affects every aspect of how you experience your tea: taste, aroma, mouthfeel, and more. This mineral profile is defined by two main parameters: hardness and alkalinity.
In order to create a custom recipe, you need to start from a “blank slate” water which contains no minerals, like reverse osmosis or distilled water. Then, by adding minerals for hardness and alkalinity, you can create your own mineral profile from scratch.
Your resulting brew will taste different depending on the particular minerals you choose for each parameter. Unfortunately, there’s no guide that explains how each mineral affects the brewing performance of your water. So we have to figure that part out for ourselves, and boy, can it get complicated.
To keep things simple, I won’t go in depth on all the different forms of calcium and magnesium one could possibly use for hardness. I’ll just say that Epsom salt (magnesium sulfate heptahydrate) is by far the easiest mineral to find and use for the purpose of adding hardness to water, and that its use is well known in the coffee world.
For alkalinity, I haven’t heard of anyone using anything other than baking soda (sodium bicarbonate), but I will be testing out potassium bicarbonate someday soon to see if it’s any better. Edit: I tried it!
Anyway, here’s my recipe:
- Concentrate: 10.14 grams of Epsom salt and 3.38 grams of baking soda dissolved in 986.48 grams of reverse osmosis or distilled water.
- Brew water: 17.5 grams of concentrate mixed into 1 gallon of reverse osmosis or distilled water.
(Technically, since a gallon contains ~3785.4 grams of water, the recipe would be 17.5 grams of concentrate mixed into 3767.9 grams of water. But that’s just being pedantic, and won’t result in a noticeable difference.)
You will need to use a scale with a 0.01 gram resolution, or better yet, a 0.001 gram resolution, and you must test that it is accurate with a calibration weight. This isn’t optional, though luckily it won’t run you more than $20.
In separate posts, I will compare my recipe to popular bottled waters, distilled/RO water, and altered versions of my own recipe.
October 29 Update
I have written a brewing guide specifically for use with this water recipe. Please use it as a reference before passing judgment on the recipe.
Also, it should be clarified that this water recipe is currently best suited to less-oxidized teas. I’m in the process of creating a different recipe to produce a thicker, richer brew from other teas.