Fire!

I recently had the chance to help with the firing of the Johanna Kiln at the St. John’s University Pottery. It’s the largest wood-fired kiln of its kind in North America, and firing it is an awe-inspiring experience.

Usually, the kiln is fired every two years, but Covid caused a one-year delay after the last firing in 2019. The kiln has three chambers, and firing generally takes about ten days. The kiln holds thousands of pieces–around 10,000 for this firing, and it takes seven or eight weeks to load the kiln before the firing. Richard Bresnahan designed and built the Johanna Kiln (and its predecessor). Richard is a master potter and has been an artist in residence at St. John’s at St. John’s since 1979. He studied with Nakazato Takashi, a Japanese living treasure ceramic artist in Karatsu, Japan before coming to St. John’s. I was in one of Richard’s first classes at St. John’s and we’ve been friends ever since.

Richard and his most experienced assistants talk about the kiln as a living thing. It might be hungry or need to breath. It may be tired or slow. Firing always begins with a Japanese-inspired lighting ceremony. If temperatures rise too high too fast, the pieces in the kiln can suffer thermal shock and crack, or even explode. So the firing starts out slowly. There are four stoking teams for each firing, each working a six-hour shift to keep the kiln fed 24-hours/day for the ten days of the firing. Usually, the first chamber is done after four or five days of firing. From that point, the fire in the front of the kiln is kept at a maintenance level, just to keep a draft going through the kiln. Richard himself almost always fires the glaze chamber, the second chamber of the kiln, which takes only a few hours. Once the glaze chamber is done, it’s on to the tanegashima chamber, the third and longest chamber of the Johanna Kiln.

The tanegashima chamber has nine stoking ports on each side, where members of the stoking teams place wood directly into the chamber. The pottery in the tanegeshima chamber rests on shelves that border the lanes under each pair of stoking ports. That arrangement allows the flames in the chamber to flow onto and around the ceramics, depositing ash, which forms a glaze, and giving the pieces in the tanegashima chamber their distinctive, beautiful and unique wood-fired appearance.

Stoking the tanegashima chamber is an amazing experience. When you look into the chamber from a stoking port, you see living flame flowing through the chamber like water. Stoking is done every ten to twenty-five minutes once the second chamber is done, and goes on around the clock until the kiln is sealed on day ten of the firing. Richard and the other stoking team leaders make the call on how often and how much to stoke, bringing the kiln up to full power slowly, then maintaining the optimal mixture of ash and flame. One spectacular part of stoking is “burping” the kiln. Often when stoking in tanegashima, the lanes are filled completely full of firewood. The fuel doesn’t have enough oxygen to combust fully, so the stoking ports are opened, one by one, to get more oxygen into the kiln. As each stoking port is opened, the oxygen-starved gases inside explode into the air outside the kiln, forming fireballs up to five feet high. It is an incredible sight!

Teams of volunteers led by Colette Bresnahan, Richard’s wife, prepare meals for the stoking teams and visitors each night of the firing, and a final, celebratory meal at the end of the firing. Richard and Colette’s three kids come back for all or part of the firing. It’s a warm and wonderful community. Old friends stop by, and artists who have works in the kiln stop by to get updates on the progress of the firing. Visitors are always welcome. If you’re ever in Collegeville when a firing is going on, don’t miss it!