In Which Ophelia and I Make Our Own pH Measuring Stuff From Cabbage
Recently, I got some litmus test strips and Ophelia and I have been pHing everything in the house. It has been a fun adventure. While researching this, I learned that some common foods have colorful dyes in them that can act as pH indicators. The most commonly mentioned is red cabbage, which contains an anthocyanin pigment called flavin that changes color according to pH. We bought a red cabbage, boiled about half of it in an inch of water for 20 minutes and then collected the juice. In order to use it, we took about 2ml of the juice, added 8ml of water, and then about 2 ml of the test material. The package of the fancy pH strips has a color guide to compare the strips to, but there is no cabbage scale available, as far as I know. We decided to make one ourselves. The pH values on the card were measured with the strips and marked here for reference. The color in the squares is Ophelia’s best attempt to imitate the liquid using colored pencils. The values seem to go from yellow/brown (basic) through cyan, then purples, then pinks (acidic). The next logical thing to do would be find some “unknowns” and try to call the pH using the cabbage juice. I am really quite surprised that this solution responds, seemingly, across the entire range. Turmeric is next. I will let you kow how it goes.