Best of 2019: Ceramic glaze made from human urine

Originally published on 21 January

For her project This is Urine, designer Sinae Kim aims to re-evaluate the potential role and value of urine, by using its inorganic components as an alternative resource to glaze in the ceramics industry.

With a population of 7 billion people, we produce and waste on average 1.5 litres of urine per person per day. In the past, urine was used for a variety of purposes, like tanning leather, doing the laundry or using as mouthwash if you were a Roman (not necessarily something we’d recommend). Urine consists of over 3,000 components, many of which are valuable, including various minerals, water, urea, and more. Nowadays, it’s uncommon to recycle urine due to the ‘ick-factor’ which means we flush valuable materials down the toilet.

Kim’s project explores the potential of human urine by using it as alternative for glaze. First, the urine is collected and distilled, separating the water from the other compounds. The remaining dark-coloured solution is then filtered, which leaves sediment consisting of minerals. This filtered sludge is then fired at a high temperature to 9 to 10 hours with 20 minutes of soaking. The mineral residue crystallises and forms an opaque glass coating on the ceramic surface. The glaze can have various textures depending on different conditions.

Kim used the process to glaze tiles and a collection of decorative vessels, which shape is inspired by the human bladder and laboratory flasks.

“I hope to not only question the ethics of disposing such a vast raw resource simply because it is considered to be an unpleasant natural process and resource, but also form a social consensus on human urine as a potential material, so that more relevant technology and industries can be developed,” Kim says.

Photos: Sinae Kim