What is "dry matter"

n. dry weight; a measurement of the mass of something when completely dry

The dry matter (or otherwise known as dry weight) is a measurement of the mass of something when completely dried.

The dry matter of plant and animal material would be its solids, i.e. all its constituents excluding water. The dry matter of food would include carbohydrates, fats, proteins, vitamins, minerals, and antioxidants (e.g., thiocyanate, anthocyanin, and quercetin). Carbohydrates, fats, and proteins, which provide the energy in foods (measured in kilocalories or kilojoules), make up ninety percent of the dry weight of a diet. Water content in foods varies widely. A large number of foods are more than half water by weight, including boiled oatmeal (84.5%), cooked macaroni (78.4%), boiled eggs (73.2%), boiled rice (72.5%), white meat chicken (70.3%) and sirloin steak (61.9%). Fruits and vegetables are 70 to 95% water. Most meats are on average about 70% water. Breads are approximately 36% water. Some foods have a water content of less than 5%, e.g., peanut butter, crackers, and chocolate cake. Water content of dairy products is quite variable. Butter is 15% water. Cow's milk ranges between 88-86% water. Swiss cheese is 37% percent water. The water content of milk and dairy products varies with the percentage of butterfat so that whole milk has the lowest percentage of water and skimmed milk has the highest.

In the sugar industry the dry matter content is an important parameter to control the crystallization process and is often measured on-line by means of microwave density meters.