Submitted to: National Egg Quality School Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 25, 2007
Publication Date: May 21, 2007
Citation: Jones, D.R. 2007. Why Measure Haugh Units?. National Egg Quality School Proceedings. p. 313-316 Technical Abstract: Most people associate the determination of interior egg quality with candling eggs. While this is the most commonly utilized method, it is very subjective and takes some skill. The Haugh unit was developed in 1937 by R. Haugh and is revered as the “gold standard” for measuring interior egg quality. This objective method of interior quality determination is based on a correlation of egg weight and height of the thick albumen. USDA Agriculture Marketing Service (AMS) has published specific guidelines for Haugh unit readings and egg grades in the US market (AMS 56.210). Haugh units are determined with the aid of a micrometer, balance, and flat surface (such as an egg break-out table). A break-out table can be useful during measurements because the mirror allows the operator to determine exactly when the micrometer comes in contact with the thick albumen surface and also allows for viewing of the underside of the yolk. Due to advances in technology, there are now electronic methods, as well as manual, for determining Haugh units.