Treating the water

The first step of the process and the one most often skipped, because water arrives free from a tap.

Why it comes first

Water is most of the product, and what is in it reaches everything downstream: extraction, fermentation, flavor and shelf life.

It is also the only input that changes without anybody telling you, seasonally and by supply.

Removing chlorine

Chlorine and chloramine are in the supply deliberately to suppress microorganisms, and they will do that to your culture too.

Activated carbon filtration removes both, and it is the minimum for anything fermented or tea-based.

Boiling drives off chlorine and does not remove chloramine, which is why "we boil it" is not an answer in a chloramine area.

Change the filter on schedule. A spent carbon filter is not neutral: it is a warm wet bed of organic material with water running through it.

Hardness and minerals

Hardness changes extraction from tea and coffee markedly, and it changes mouthfeel.

Reverse osmosis or deionization gives a reproducible blank, which is what a producer selling the same drink in two towns needs.

Fully stripped water can taste flat, so building minerals back to a specification is the professional answer, and it makes the water an ingredient with a number rather than a variable.

Keeping treated water clean

Treated water has had its residual disinfectant removed, which makes it a better growth medium than what came out of the tap.

Use it promptly, do not store it warm, and sanitize the storage.

A tank of filtered water standing over a weekend is a microbial culture that will seed every batch made from it, and it is a genuinely common cause of an unexplained spoilage problem.

References