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How to Test the pH Level of Citrus Juices

The pH level of a solution is a measurement of its acidity, and is an important tool for food scientists. Given that citrus fruits are among the more acidic foods common in the human diet, it is no surprise that they are common subjects for acidity testing. Using easily obtainable pH testing strips, you can conduct your own pH tests to determine the relative acidity of various citrus fruit juices.

Instructions

- 1
  Slice the citrus fruit in half, using a large chef's knife. If your test includes multiple types of fruit, thoroughly wash and dry the knife in between each cut.
- 2
  Mark several sanitary, disposable cups with the name of the fruit you will test, using a permanent marker.
- 3
  Squeeze a small amount of juice from each fruit into its corresponding, pre-marked cup.
- 4
  Lay one strip of pH test paper in front of each cup.
- 5
  Insert a clean, disposable pipette into each cup of liquid. Take a small amount of liquid into the pipette, and deposit one drop onto the corresponding pH test strip.
- 6
  Allow the test strips to process for 10 minutes.
- 7
  Check the color of the pH strip against the color chart provided by the manufacturer to determine the specific, numerical pH level of each juice. All of your test strips should be pink or red, indicating the presence of acidity. In general, the darker red the test strip, the more acidic the liquid.

Nature