How to extract citric acid from fruit

Updated April 17, 2017

Eating citric acid makes your eyes water and your mouth pucker. Citric acid causes the sour taste in many fruits and other foods. People use it as a food preservative. Fifty grams of citric acid can be extracted from 1 litre of fruit juice. Lime, orange, and lemons contain a high volume of citric acid. Extraction of citric acid from fruit is an easy process. Simple materials available at your local hardware store are needed.

Pour 1 litre of lemon juice and 1 tablespoon of calcium hydroxide into a large glass flask. Any fruit juice can be used.

Heat the flask in the microwave for 1 minute. Mix the solution by swirling the flask in a circular motion. This turns citric acid into calcium citrate.

Place the flask in the freezer for 5 minutes to cool the solution.

Strain the solution through filter paper. The calcium citrate collects to the filter paper.

Scrape the calcium citrate off the paper using a butter knife. Collect the calcium citrate on a separate piece of paper.

Repeat Steps 1 to 5 until you collect 100 grams of calcium citrate.

Place the calcium citrate in a cooking pot. Pour 70 grams of sulphuric acid. Cook the solution to 150F. Check the temperature using a cooking thermometer.

Heat the solution for 10 minutes. Stir the solution occasionally. Carbon evaporates and leaves the citric acid.

Let the solution cool. The remaining solution turns to solid citric acid.


Calcium hydroxide is available at your hardware store.


Sulphuric acid is very corrosive. Safety gloves, goggles, face mask and clothing should be worn.

Things You'll Need

  • Lemon juice
  • Calcium hydroxide
  • Large glass flask
  • Freezer
  • Filter paper
  • Butter knife
  • Cooking pot
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