Stone Milling Barley

By Amrita Ray, Ph.D. | Northern Crops Institute

Barley is one of the most important and ancient among the cereal crops domesticated about 10,000 years ago. The grain mainly comprises of pericarp, aleurone layer, endosperm and embryo; has various health benefits and helps in disease management. Barley is usually milled to flour and utilized to develop food products like flatbread, pasta, bakery products etc. mainly with incorporation with wheat; it is also explored in the preparation of porridge.

Barley can be milled as whole grain flour or fractionated in its various botanical components using different milling equipment. At the Northern Crops Institute (NCI), we wanted to explore barley milling using our stone mill. Stone milling is an ancient technique which typically produces whole grain flour. In this system, multiple physical forces, namely shear, compression, and abrasion, are used to mill grains in between two horizontal circular stones dressed with furrows and placed one on top of the other. Usually, the bed stone is fixed and the other (runner stone) rotates; the grains are fed to the stone and ground. The degree of fineness of flour is controlled by adjusting the gap between two stones. The advantage of whole grain flour is that it contains all the components of the grain; thus, nutrients of all the grain components stay in the flour.

 The NCI stone mill can produce whole barley flour with more than 95% extraction rate. We used dehulled barley that was milled at a medium to narrow stone gap producing a bright whole flour. The stone milled whole grain flour showed very little redness or yellowness and can be utilized to replace refined wheat flour for product development. We produced a fine flour with more than 80% going through a 60mesh (250ยต) sieve. The particle size distribution is suitable for incorporation with whole wheat flour as well as independent product formulation.

We developed stone milled whole grain barley pizza crust with good sensory and textural properties. Barley bread can also be prepared by incorporation with wheat flour; other products like cookies, crackers, pasta will be good nutrient rich alternatives. Being a good source of protein, mineral and fiber, whole grain stone milled barley flour can be utilized as a nutrient rich alternative grain flour for product development.