About Soda Firing

Spraying the soda solution in at 2300*F

Pulling the soda rings to see if the pottery has enough glaze.

In 2014 the first Soda Kiln was built in Prince George.

In 2011, Leanna Carlson tested her hand dug clay in a variety of kilns at Medalta in Medicine Hat Alberta. Although the clay performed well in all the atmosphere kilns (Wood, Salt and Soda), it was especially attractive when fired in the Soda Kiln. The orange flashing and the bright colors brings a spontaneous uniqueness to the pottery that no other type of firing can achieve.

Soda firing is an atmospheric firing technique where “soda” is introduced into a kiln when it's above 2300°F. It is sprayed in with a garden sprayer or dropped in wrapped in newspaper. The soda that we use is: sodium bicarbonate, also known as baking soda, and sodium carbonate, which is also known as soda ash.

The soda vaporizes and is carried on the flame throughout the kiln. The soda vapors create a glaze when it lands on a piece (or a kiln post, or the wall of the kiln). Wherever the flame travels- so does the soda. When placing the pieces in the kiln during loading, you have to think carefully about when and where you want a piece to get lots of soda, or when and where you want a piece to be more protected. The kiln must be evenly loaded because the flame will travel on the path of least resistance (and therefore the soda will also be traveling on the path of least resistance). You also have to think about whether or not the piece is glazed. The soda is basically a glaze, and when two glazes mix, they can react chemically with one another and run down the side of the piece. It’s beautiful when you can control the run- but can be disastrous when it gets away from you!

What is the history of soda firing? Where did it come from?

The predecessor of the modern day soda firing, is salt firing. It is believed that salt firing began in Germany in the 13th century. As many things go, it was most likely come upon by accident. Perhaps some salt soaked wood (from pickling barrels?) was tossed into the kiln for the wood fuel. The salt vaporized and glazed the pieces inside the kiln. It was a great time saving measure. No need to glaze the pieces before they went into the kiln. Old German jugs were salt glazed, along with tankards and sewer pipes. The pieces that we think of as early American traditional ceramics from the southwest corner of the US were also salt glazed.

In the 1970's, several grad students at Alfred University started researching sodium alternatives to salt firing. With their investigations into soda bi-carbonate and sodium carbonate, soda firing was born.

The Kiln was built by Bruce Dehnert from New Jersey.