In modern grinding processes the field of application for vitrified bonded wheels is constantly increasing. Regarding the grinding itself, the advantages of these wheels are obvious. But their ability to be dressed offers further benefits as well. Usually in-machine dressing is favorable. Nevertheless, in-machine dressing causes non-productive-times during which no part production is possible. To reduce this disadvantage, a powerful monitoring is needed in order to minimize the number of needed dressing strokes and to verify the created grinding wheel geometry. The approach applicable for industry is to use an acoustic emission sensor for monitoring, which is usually integrated in modern grinding machines to minimize the air grinding time. This article also provides basic knowledge about Acoustic Emission.