This is the final thesis of the faculty of Industrial Design Engineering of Delft University of Technology in collaboration with the Politecnico of Milano (Italy). The assignment is commissioned by Re-Worked (UK) and the main research question is formulated as: ‘how can waste coffee based-materials be designed both technically and experiential to optimize the material (and product) experience?’ This experience is a result of the material’s technical properties and its experiential properties. A study of literature and additional experiments were conducted to create understanding of the field of bio-composites. The technical boundaries were mapped out. Waste coffee grounds can be used as filler to create bulk and in general decrease the technical properties of a matrix. Short or long fibres can be added to enhance the performance of the material. Bio-based polymer matrixes are in development and becoming available commercially. The experiential properties are a result of the aesthetic experience, the emotional experience and the meaning experience. Materials based on coffee have preordained meanings?of being sustainable, natural and waste materials. The aesthetics of the material and the product function and context can be used to communicate to these preordained meanings. Many qualities are best perceived when they are multi-sensory, although designing paradoxical experiences can lead to more exiting emotions. Imperfections of materials link to the pillars of this?thesis: D4S, wabi sabi and standard unique. In addition imperfections are indispensible in communicating the sustainability and naturalness of materials, especially if they occur as a sign of the maturing of a material. Embracing imperfections as an aesthetic creates economic opportunities for the industry of bio-composites and creates opportunities to have more rich and enduring relationship with the user. Waste coffee grounds are small particles that can contain nutrients for plants and greens and they can biodegrade. The matrix determines the technical behaviour of the composite material and how it can be produced and manufactured. Moisture in the grounds can influence the technical properties of the material. This waste material does not evoke negative associations and its colour is the strongest connection to coffee. This is a great influencer of the meaning experience and associates to meanings as natural, organic and sustainable. Coffee smell seems to be important because it recalls memories. Fibres and pigments increase imperfections in the material surface that enhance the earlier mentioned meanings. The domain for the new material design is: ‘user-relationships between waste coffee ground-based bio-composites in 2015’. The new context of 2015 includes themes that relate to this domain, such as ‘loose ends connect’, ‘visual deception’, ‘material driven design’, ‘embrace imperfection’, ‘dynamic bonding’, ‘wake up and smell the coffee’ and ‘subconscious misbehaviour’. The vision statement that was derived from this is ‘I want people to feel desired by the material and captivate them in the course of material bonding’. To fulfill this vision in material design, the interaction has to be a ‘tempting exposure’. It was found that the material has to be modest and provocative in order to evoke this interaction. Modest and provocative materials have qualities that can be contradicting and others that can enhance each other. New materials based on waste coffee grounds will not be designed for their technical properties, but rather for their sensorial properties. Three material concepts are proposed, which are Cofflexi (a flexible rubber/silicone composite), Café Maché (a lightweight recycled paper composite that is fully biodegradable) and CapPurcino (bio-polyurethane composite material). A workshop, reflection and evaluation helped to decide which of the materials were most valuable to continue to work with in this thesis. It was concluded that Café Maché is the best match to the vision as it creates a rapidly changing bond with the user. Suggested product categories to target with this material are nutrient packaging (for coffee products) and events. CapPurcino is most promising for Re-Worked to implement on a short term. The company is already working with a PU specialist that is developing the bio-based PU polymers. The material’s imperfect aesthetics and potential to mature in time due to bad UV-resistance are a perfect fit to the vision. The final product proposal is Cof2Grow: a product set to grow greens at home. It consists of tablets and a pot. The tablets contain seeds for greens (cress, alfalfa and bean sprout) and they are packaged and filled with Café Maché that provides the seeds with nutrients. Additional nutrients may need to be added for optimal germination and growth, but this needs to be further developed. After the greens are consumed, the entire tablet can be disposed in the organic waste, because it will fully biodegrade. The pot is made of CapPurcino using a principle of standard unique to create authentic pots in each mould. The tablets fit the pot and the pot has a drainage system that collects and re-feeds the redundant water to the tablet. The pot is 100% bio-based, reused and matures in time.