Silverskin, the delicate outer layer of the coffee bean discarded during the roasting process, has gained attention for its diverse applications. Chemically, it consists primarily of cellulose and hemicellulose, which contribute to its fibrous and brittle characteristics. It also contains up to 20% protein, around 3% lipids, and essential minerals like potassium and magnesium, though in smaller amounts compared to the coffee bean. Additionally, silverskin contains antioxidants, including polyphenols and chlorogenic acids, albeit in lower concentrations than those found in coffee beans (Mendes dos Santos et al., 2021).

One of the most promising applications of silverskin is in skincare. High in  phenolic compounds such as chlorogenic acid, and vitamin precursors provide antioxidant and anti-radical properties that help protect the skin from oxidative stress and premature aging. Additionally, the lipids extracted from silverskin, which have a composition similar to cocoa butter, are highly valued in cosmetic formulations for their moisturizing and skin-conditioning properties.

Additionally, caffeine, another key compound, offers multiple benefits for skin and hair care. Its vasoconstrictive properties can help reduce dark circles, brighten and firm the skin around the eyes, and improve scalp health while stimulating hair growth. These bioactive components make silverskin an appealing addition to cosmetic formulations, offering natural and sustainable skincare solutions.

Silverskin’s potential is not limited to non-food applications. Its nutritional composition, which includes dietary fiber, protein, and antioxidants, makes it a viable ingredient for food products such as cereal bars, where it could enhance their nutritional value. However, taste, texture, and safety considerations must be carefully addressed. Additionally, regulatory approval is required before silverskin and its extracts can enter markets such as the US and the EU.

Furthermore, silverskin is being repurposed for sustainable energy solutions. Some large roasting companies, including J.J. Darboven in Germany (Tomblog, 2018) and CF Nielsen & BKI Foods in Denmark (CF Nielsen, n.d.), have begun pressing silverskin into pellets for use in biogas plants, contributing to efficient waste management and renewable energy production.

Sources: 

• CF Nielsen. (n.d.). Agricultural briquetting cases. CF Nielsen. https://cfnielsen.com/agricultural-briquetting/cases/
• ICO 2024, Beyond Coffee: Towards a Circular Coffee Economy coffee-development-report-2022-23.pdf
• Mendes dos Santos, É., Malvezzi de Macedo, L., Lacalendola Tundisi, L., Ataide, J. A., Camargo, G. A., Alves, R. C., Oliveira, M. B. P. P. (2021). Coffee by-products in topical formulations: A review. Trends in Food Science & Technology, 111, 280-291. https://doi.org/10.1016/j. tifs.2021.02.064
• Tomblog. (2018). Tomblog. (17 September 2018). J.J. Darboven: Kaffeehäutchen als Energiequelle. Coffee News Tomblog. https://coffeenewstomblog.wordpress.com/2018/09/17/j-j-darboven-kaffeehaeutchen-alsenergiequelle/