Sustainable materials from hop stem

Bast fibers derived from phloem tissue are widely recognized for their availability, durability, mechanical properties, and wide range of applications. These naturally occurring fibers have garnered significant interest from both the scientific and industrial communities due to potential use in textiles, composites, and bio-based materials, aligning with the global trend toward more sustainable and renewable production methods. Hop (Humulus lupulus), a dicotyledonous plant belonging to the Cannabaceae family, alongside hemp, is primarily cultivated for flowers, which are extensively used in the brewing industry. Although hop bast fibers have interesting potential uses, they remain underexplored and underutilized. Hop bines, which contain these fibers, are often mistakenly regarded as an agricultural by-product of the crop. This review presents a deep and comprehensive analysis of the current state of knowledge concerning the valorization of hop stalks for material innovation and applications. The review considers contemporary strategies for transforming hop fibers into high-value materials, such as non-flammable panels, textiles, structural composites, and other innovative products. To the best of current knowledge, this review represents the first effort to consolidate existing research on hop bines and offers a critical analysis of properties, processing methods, and potential applications in sustainable material development. By underlining recent studies, technological advances, challenges, and opportunities, this review highlights the untapped potential of hop fibers as a raw material for sustainable materials development and potential integration into industrial applications. This review specifically focuses on the utilization of Hop (Humulus lupulus) stem fibers, a neglected by-product of the brewing industry, and examines potential contributions of hop stem fibers to sustainable material development.