Dandaweedman

This was originally posted by Pfc J at Breedbay...

Red cabbage contains a pigment molecule called flavin, an anthocyanin.
This water soluble pigment is also found in apple skin, plums, poppies, cornflowers, and grapes.
Very acidic solutions will turn anthocyanin a red color.
Neutral solutions result in a purplish color.
Basic solutions appear in greenish-yellow.
Therefore, it is possible to determine the pH of a solution based on the color it turns the anthocyanin pigments in red cabbage juice.
The color of the juice changes in response to changes in its hydrogen ion concentration. The formula for pH is the -log[H+].
Acids will donate hydrogen ions in an aqueous solution and have a low pH (pH < 7).
Bases accept hydrogen ions and have a high pH (pH > 7).

Chop the cabbage into small pieces until you have about 2 cups of chopped cabbage.
Place the cabbage in a large beaker, stove pot, or other heat proof container, and add boiling water to cover the cabbage. You could also place about 2 cups of cabbage in a blender, cover it with boiling water, and blend it.
Allow at least ten minutes for the color to leach out of the cabbage.
Filter out the plant material to obtain a red-blue-purplish colored liquid. This liquid is your pH drops.
The range of color change with cabbage juice is as good, or better, than commercially available pH drops.

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Peace seeker

wow...natures own ph meter

plus red cabbage is good for us. As well as all the red vegies (eggplant, red brocoli, etc)

Dandaweedman

You are a goldmine of pertinent information.

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sixpiece

yeah what about phenolthalein solution . etc.. that can be purchased for $5 . general hydroponics , etc.. but i recommend a pH meter in general though that's interesting danda

Dandaweedman

Yeah, as I found out today.
Using drops in water with nutrients in it is tougher than first thought. The natural colouration of the organic nutes foils my attempts to check the ph.

Back to the pen...

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