Sourdough Jar / Pot

How are they made?

Form

These stoneware sourdough pots are hand-thrown on a wheel before being trimmed and left to dry, slowly, over a couple of days. At this stage, when the clay is not too soft to touch but not too dry, which is called ‘leather hard’, finishing touches and intricacies are applied. The ceramic pieces must be dried very slowly at a consistent temperature to prevent them cracking. Unfired pots are often termed ‘greenware’.

Additionally, they are fired to 1050 degrees celsius, which is called a ‘biscuit’ firing. During this firing, the pot has made the transformation from clay to ceramic. At this stage the piece is sanded, washed, and sometimes waxed, ready for glazing.

A glaze is a combination of clay, silica and a flux, plus any oxides, all of which fuse at certain temperatures. When working with these materials the possibilities are almost infinite. Most of our glaze materials are sourced via a wholesaler who sources materials from all over the world, but we sometimes source our own materials too, such as wood ash, which is collected from sources in South Yorkshire and washed and processed by us at our Sheffield studio.

Glaze

The glaze materials are mixed in water, sieved twice and suspended in water – the ratio of water to glaze is measured using a hydrometer. Once we are happy with the consistency we apply the glaze to the ceramic by dipping, pouring or brushing. The biscuit fired pot soaks up much of the water and leaves a coating of powder on the surface. We ‘fettle’ away any unwanted drips with a small knife and clean up any areas of the pot which will touch the shelf of the kiln to prevent them from fusing, then fire again, in an electric kiln, to 1250 degrees celsius for a period of 14 hours, plus cooling.

Care Instructions

These ceramics differ from some mass-produced ceramics in their composition. They are made carefully by hand and we recommend washing them by hand too, although they are dishwasher safe. Regular dishwasher use may shorten their lifespan with chips and cracks being more likely. To help prevent crazing in the teapots, it is best practice to warm the teapot with warm water before using.

Just like any object, with use wear and tear is more likely and ceramics are obviously breakable. In the unfortunate event you have a chip or breakage, there isn’t an awful lot you can do to restore the piece, but we can recommend Kintsugi (you can purchase DIY kits online).

A look behind the product. CRAFT