Brewers' grain as an alternative organic filler to wood powder

Abstract

The Korean paperboard industry uses wood powder as an organic filler to improve paperboard thickness and to reduce drying energy consumption. However, given the mixed wood base of this material, industry has great interest in exploring new biomass alternatives to maintain stable supply and price of organic fillers. In this study a new non-wood organic filler from ground brewers' spent grain (BG) was evaluated. The study identified the effects of BG filler on paperboard properties and imputed drying energy consumption by measuring the physical strength of handsheets and the after-pressing moisture content of wet webs containing BG filler. The BG filler increased the bulk and reduced the imputed drying energy requirement more effectively than commercial wood powder. BG filler fractions containing larger particles increased the bulk of the paperboard and decreased imputed drying energy requirement more than those fractions containing smaller particles, but this was at the cost of a decrease in paperboard strength. For commercial use it will be important to control the particle size of BG filler to obtain the desired bulk, strength, and drying energy consumption of paperboard.