Archaeologists hope to discover more about Angkorian civilisation by using ancient pottery-making techniques

The Angkorian Khmers were prolific ceramics makers, and the Angkor Archaeological Park is still littered with fragments of ancient pots and bowls that were used in households and temples for storing water, foods, oils and other materials.

Finding pieces of them today is, literally, just a matter of a walk in the park. It’s harder, however, to understand how they were made and determine what they can then tell us about the people who lived there.

Seeking to build on that knowledge, the Ecole Française d’Extreme Orient (EFEO) has designed and built an Angkor-era kiln in the middle of the school’s tropical gardens.

Over the course of a week, the researchers fired up two separate lots of ceramic ware as part of their efforts to understand the techniques involved, and also how the Angkorians created natural glazes, which occur as a result of the process rather than from applying anything to the wares before they are fired.

The first attempt ended explosively after they allowed the temperature to drop. Refuelling the oven again, the temperature soared too quickly, shattering the pieces inside.

“It was a little bit for the fun of it,” admitted Armand Desbat, an archaeologist from the school who has been researching Angkorian ceramics for the past seven years, when asked about the EFEO’s motivation.

“But it’s also for the pedagogy. We start to see how they created natural glazes, how long they needed to fire the pottery, how much wood was required, all of these things.”

The Angkor-style kiln. Nicky Sullivan

Understanding the techniques, glazes and materials enables the researchers to distinguish and date the ceramics and the workshops where they were produced, yielding clues about trade and cross-cultural exchanges, or the periods during which temples were in use and particular sites inhabited.

The Angkorian Khmers used a kaolinite clay, which can be red or white. It appears to be homogenous in composition, which has limited the ability of the researchers to distinguish production sites based on chemical analysis of the pieces they find.

Many workshops, however, used unique designs that can be fixed to a particular time and location. The glazes are also different colours in different locations, which helps to identify the origin of pieces.

Desbat and his colleague Nicolas Josso constructed a Dragon kiln, based on a design originally seen in China, though the Khmers would very likely have adapted it to their own needs.

“It is difficult because, unlike in Thailand, where they made their kilns in the ground, here they were above ground, so they disintegrated once they were abandoned,” said Desbat.

From the outside, the kiln is a clay hump-shaped shell about three metres long and one metre wide. One large and three small holes at the front allow the fire inside to be fed with air and wood, while a flue at the back belches out the smoke. Along the sides, bricked-in holes provide access to the interior and gauges monitor the temperature. The fire burns in a recess at the front while, on a brick platform behind, the pots and bowls cook at temperatures hotter than lava.

It took heats of up to 1,200 degrees Celsius and 50 hours to successfully fire the pieces inside. This meant a constant vigilance had to be maintained as the fire consumed roughly 10 cubic metres of wood through two firings of about 70 pots and bowls.

The researcher’s second attempt to use the kiln was far more successful than the first. On Wednesday morning they pulled out 34 intact bowls and pots, some with traces of a naturally formed glaze on their exteriors.

They were rough and rang with an almost metallic tone when rapped. The insides had petrol-like traces of blue-green created by the burning of rice husks placed in them. The exteriors were blackened in uneven patches.

“I’m very content,” said Desbat. “It has gone beyond my expectations.”