Iron Age Life: Experimental Archaeology in Denmark

Day two

The morning of the second day was bright and hot.  By this time, I had ceased to be surprised by the sun high in the sky by the time we awoke.  The sun set around 11 at night and rose again at 3 or 4 in the morning.  No one had a watch, so we were never sure of the time.  Without getting into the metaphysical nature of things, that was for the best.  It helped our minds come to terms with the juxtaposition of our modern expectations and the activities at which we were playing.  

The day was hot with the full sun of summer.  Before long most of us women were without our under dresses, the men without their shirts, and the smaller children from the other families wore no clothes at all.   Lejre allows multigenerational families to live for a week on their Iron Age Village and 19^th century farms throughout the summer.  So, for this week we were one of the four families.  As we conducted our experiment, we called the families over to demonstrate what we were doing and to explain the process.  For the most part we were isolated in our own little project located on the outer edge of the village.  The secrecy and isolation of the smithing clans throughout Africa documented by Schmidt and others seems logical now.  Smelting iron requires space and produces a lot of smoke, fire, and debris that no one would want near their homes. 

Our tasks for the second day were twofold; the first step was to produce charcoal.  Coal was not used during the Iron Age to smelt iron.  In the United States it was not until 1837 when ore and coal deposits were discovered near to each other that smelting with the fossil fuel was widely embraced (Gordon).  Lethra is supplied with pallets of birch for the communal fire and, unintentionally, for iron smelting.  Near the blacksmith shop along the path that runs perimeter of Lethra is a small pit with deep sloping sides.  When first we saw it during our initial a tour of Lejre, I thought it was for roasting whole pigs.  In truth the pit is used for producing charcoal.  In the center of the coaling pit five of us began stacking logs vertically in the shape of a donut.  The center of this circle of logs was filled with charcoal.  A chimney of alder was constructed to maintain the open center.  It also was useful in maintaining a solid construction as the charcoal pile grew in height.  Each course of wood was about five or six logs deep.  As the charcoal pile grew in height, sod was piled on the outside of the pile to keep the wood vertical and smother the fire once the coaling pile was lit.  Were the fire not smothered the wood would be reduced to ash and not charcoal. 

 

Bog ore broken into smaller pieces.

Placed between each course of wood was a layer of iron ore we had broken off larger blocks of ore.  Iron ore needs to be roasted prior to using it in a smelt.  The roasting process evaporates water vapor from the rocks and causes the rust in the ore to take another oxygen molecule to become iron oxide, FeO3 or FeO4.  By placing iron ore between the layers of wood, it took care of both necessary steps.  By alternating layers of wood and ore, the charcoal pile grew three courses high to measure about 42 inches tall.  At the base the circumference was 174 inches and the mound tapered so that the top was about 40 inches in circumference.    

  

Stacking wood to make the charcoal pile.

The charcoal pile appeared as a small volcano when we stood back to view our efforts.  A few of us had crushed fingers and toes from the few times the stacks of wood had collapsed.  It was early afternoon.  The other families and museum visitors had gathered to see the culmination of the morning’s work.  Since we had an audience we had to light the charcoal pit with time period correct items.  Parents sent their children off to get flint, tinder, dry bark and moss.  With an audience I struggled to catch a spark on the moss and finally passed it off to Kim.  After a few skilled strikes he passed a piece of smoldering plant wrapped in straw to me.  “Blow on it” was the silent command.  So I did.  After a very long breathless minute, flames leaped up in my hand.  For a moment the charcoal pile did look like a volcano as the flames climbed down the alder chimney.  Then the last piece of sod went onto the top, and began white smoke began to seep out of the mound. 

Trying to catch a spark to light the charcoal pile. 

Lighting the charcoal pile and burning my fingertips in the process.

“Its all right,” Kim said to my worried hands.  “To know that everything is going well inside the mound, just use your nose”.  Charcoal is forming when the smoke smells wet and the smoke will be white.  If the smoke gets dark or smelling like tar then the fire is being smothered.  When that happens a small air hole needs to be opened at the base.  If flames appear, throw lots of dirt on it.  It’s pretty easy.  We also had to watch the mound until all the charcoal was formed: 24 hours a day for the next few days.  The wind made it difficult; it trapped the smells among the trees.  Tar and smoke mingled in the air.  You had to place your nose right next to the warm soil where a fire burned and struggled for life inches away.  It could also burn at different rates within the pile; the top could burn better than the bottom or the windward side different than the leeward side.  There was lots of sniffing and to the curious visitor we must have made quite a sight, sniffing around a smoking pile of dirt.       

The charcoal pile with smoke rising through the dirt creating a haze in the air.

Two of the girls from our group working the clay and hay with their feet.

The guys making billets of clay and stacking them. 

Once the charcoal pile was burning, we began constructing the bloomery furnace.  Quite a production line began that would perhaps have impressed even Henry Ford.  Two of the women from our group mixed the clay and straw we had gathered the day before with their feet.  Two of the men reconsolidated the pile, another two formed billets of clay, and two or three of us took the billets blending them together to build the furnace.  The stack must be a meter high, Kim said. When we stared at him, he explained that was about the height of a man’s belt.  We decided then to keep the taller men away from the bloomery stack.  The walls began down inside the pear shaped pit we had constructed.  They were about three inches thick.  The point of the pear was where the trough was and was not built up with clay until the walls were level with the ground.  This created a window that would be to be sealed with a door on the day of the smelt.  Quickly the furnace gained height.  Too quickly in fact, the clay was too wet to support the weight.  After several hours of work the walls began to slump.  We had to cut away about ten inches of our work. We decided to let the base dry overnight so it could take the weight of the additional height.  There was nothing to do but wait and smell the charcoal as it burned.    

“It will be fine,” Kim said with a smile and a wave.  It was closing time for the museum and time for him to go home.  Everything was now in our hands.        

It was a cool night and damp.  A light rain fell as I forced myself from my warm bed.  We had discussed taking shifts throughout the night before I had done to sleep.  It was predawn and no one had come to wake me.  Panic set in.  What if the charcoaling pit had gone out? What if it had caught on fire and everyone was asleep? I hurried down to blacksmith shop and was reassured to smell no tar, see no fire, and find three of my ‘family’ sleepily tucked away in the shelter of the blacksmith’s shop.  At the start of the night everyone had stayed to watch the pile and as the hours moved by unmarked, the number of sentries had dwindled.  With little protest, these last sentries sought sleep.  The rain stopped for the sun to rise.