The design specification for our new range of ceramics was that they should be beautiful, tactile, practical to use on a daily basis, dishwashable, white, handmade and affordable. The new range includes coffee cups, tea bowls, rice bowls, plates, and carafes. The cups had to be capable of being made in 3oz, 6oz, and 8 oz sizes to fit different types of coffees, espresso, flat white, and americano.
The inspiration for the design was found in St Ives Harbour while watching a lovely old yacht on the visitors mooring I was struck by the shape of the hull which had a gorgeous 'tumblehome' curve to its hull.
I experimented with throwing these shapes on the potter's wheel until I had a set of proportions which looked good at different sizes. I carved custom throwing ribs out of old plastic bank cards to help make the replication of the shape easier. When I fired the prototypes, I loved the way in which the pots nestled into my hand as the clay curved in at the top and bottom.
The next decision was about the thickness of the sides of the pots. I decided to have quite thick sides to make the pots resilient and also to give them a high thermal mass to keep food and drink warm longer without being too hot to hold. In use, this seemed to work well. The pots absorb some of the heat immediately and then retain the residual heat.
There are two types of bottoms on hand thrown pots, wire cut and turned. The first is cut off the wheel with a twisted steel wire. The second is placed back on the wheel with the rim downwards and carved into the base with a turning tool to produce a foot on the bottom of the pot.
I decided to use a wire cut base on the cups, and a turned recessed foot on the bowls and plates because I wanted the tumblehome line to go from the top to the bottom of the pot without interruption.
There are numerous white glaze recipes, and I selected three different ones to experiment; zirconium white, tin white and dolomite white. Dolomite produces a lovely matt finish and in many ways is my favourite but rejected it because it can become stained with use. Zirconium provides a very stark dense blue white (refrigerator white) which can look stunning, but with use sometimes left scratches from metal utensils. The glaze I chose is a tin white, it has a lovely creamy old English white tinge to it and has proved to very forgiving when glazing and practical and resilient in everyday use.
I decided to glaze the cups and bowls thoroughly on the inside but half way down the outside. The glaze is poured into the pot, swirled around and then in a single movement the pot is inverted and dipped halfway down into the glaze. It is a quick and efficient way of glazing which cuts down on the number of unwanted dribbles on the pot. The plates are glazed inside and left as natural clay outside.
The half glaze technique produces a lovely effect with the smooth glaze contrasting with the rougher texture of the clay. It also has a practical benefit as the rougher texture makes the cup easier to hold.
The final element in the design is the clay itself. I experimented with different amounts of grog and iron in the clay and finally opted for clay with low levels of both giving a smooth white clay body which I like with the tin white.
So there you have it, the tumblehome range of coffee cups, I hope you like them.
Illustration by Viola Watkins.
