The weight lost by a ceramic compound during firing. The loss is due to water and organic materials that turn to gases. It is assumed the sample has been boil dried. Some labs also do 25-100C LOI.
For a detailed test procedure, see the LDW test.
Enter LOI percent value
The Physics of Clay Bodies
Learn to test your clay bodies and recording the results in an organized way and understanding the purpose of each test and how to relate its results to changes that need to be made in process and recipe.
Atterberg Limits on Wikipedia