Indicator?

Indicator may mean:

In chemistry:

pH indicator, a chemical detector for protons in acid-base titrations
Redox indicator, a chemical detector for redox titrations
Complexometric indicator, a chemical detector for metal ions in complexometric titrations
Zeta potential, a property of interfaces in fluids for Zeta potential titration
In biology:

Indicator (genus), a genus of birds in the honeyguide family
Environmental indicator of environmental health (pressures, conditions and responses)
Ecological indicator of ecosystem health (ecological processes)
In economics:

Technical indicator, a tool used in the technical analysis of financial securities
Economic indicator or business performance indicator
In engineering and mathematics:

Indicator function of a subset of the domain, a concept in mathematics
Dial indicator, an instrument that measures small distances
Indicator diagram, a graph of pressure against stroke within a piston engine
In society:

Neighborhood indicator describes certain quality of a neighborhood
A synonym for the Turn signal of an automobile

In this case it happens to be water in which 2 lots of purple sprouting broccoli have been blanched, to leave a most magnificently emerald vegetable and this liquid.
On the right: ''As is'',
on the left: + the addition of 0.25tsp white distilled vinegar.
I couldn't be harassed to add it drop-wise, titration fashion, but similarly couldn't find of my heart to chuck it out without a bit mess about.

Well! You HAVE to.
Don't you????