What is Bagasse? Lets start with the easy stuff. It's pronounced: . What is it? Bagasse is a plant fiber. More specifically, it is the fibrous matter that is left over after the production of sugarcane, sorghum or agave. So in a word, it is bio-waste. Historically, bagasse was treated as unusable and disposed of - thrown away, burned or left in open piles to rot. It was not seen as a useful by-product. Fortunately, things have changed and bagasse is being seen as a valuable, renewable resource. It is currently being used in a number of applications worldwide, including power production, tree-free paper production and in some countries it is being investigated as a viable base for livestock feed.