How to Determine the Moisture Content in Liquid

Moisture content, also referred to as water content, is the amount of free water present in materials such as soil, rock, ceramics, fruit, liquids or wood. It can even be measured as a component of a gas. Moisture content calculations can be applied across a wide variety of scientific and technical areas of expertise, and the value of moisture in the sample is expressed as a ratio that can range from 0 (completely dry) to the value of the porosity of the material at saturation, given on a volumetric basis.

Things You'll Need

• Sample of liquid
• Sample container
• Heat-resistant beaker
• Drying oven
• Calculator

Show More

Instructions

• 1

  Take a direct measurement by using a known quantity of the liquid you wish to test and drying it in an industry-approved laboratory drying oven at a temperature that corresponds to the liquid (the sample or the water in the sample) with the lowest boiling point. This depends on the material your sample contains. At the boiling point, one of the materials will evaporate, leaving you with a "dry mass" of sample (which is actually a liquid). (Moisture content equals wet mass minus dry mass divided by the density of water multiplied by the volume of the sample before drying.) Weiss Gallenkamp manufacture and supply suitable drying ovens for this purpose, according to the company's website.

• 2

  In the laboratory, use a chemical titration to determine moisture content. As reported by Sigma Aldrich, an example of a suitable method is the Karl Fischer Titration, which allows you to calculate the mass loss on heating optionally in the presence of an inert gas or after the process of freeze-drying (not an identical technique, but comparable).

• 3

  In the food technology industry, the Dean Stark Method is used as an alternative. According to the American Society For Testing and Materials, the equation required here is: The fraction of total evaporable moisture content equals the mass of original sample minus the mass of dried sample divided by the mass of dried sample.

• 4

  As a further alternative, if you already know the individual values, you can apply the basic equation: Volumetric water content is equal to the volume of water divided by the total volume of liquid and air in the sample.