Difference between revisions of "Oven Building"
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There have been a couple of oven attempts at a few long shows over the past few years. These ovens have been partly due to the efforts of Ted Jones and a few other individuals. My thanks must go to those people. Without their interest I wouldn't get to play with so much mud. Before two years ago I would never have attempted an oven without their encouragement.
The basic principle of an oven is a mound to put dough in which retains heat for cooking purposes. The 1992 Brockhole oven was built so that a fire was not actually lit in the oven at the time of baking. This eased the problem which we had during the Brockhole 1991 show where we kept burning the bread. More details about cooking methods at the end.
All of the ovens from our period which have been excavated have been in houses, not built in the open. Usually these were separate 'bakehouses' where all the various stages of baking went on from grinding the grain to the baking. The 'Ofn' was one of the "many things a farmstead must have." However, if they wanted bread in a tented encampment they must have sometimes built them outside. According to surviving literary evidence the ovens could be big enough for a man to fit inside, as some ovens discovered by archaeologists have been. At West Stow half a sunken floored building was occupied by the remains of a large clay oven 3'6" long. Its floor was of clay, 2 ½" thick, with a layer of flints, with 6" thick walls at it's base. North Elmham yielded an oven of similar size. At Porchester in building S11, probably the bakehouse serving the hall, there was an oven built largely of re-used Roman tiles and some lumps of limestone set in clay. The walls were about 15" thick and the floor had been considerably worn with use. It had been built over the remains of an earlier oven 3' x 5' in area and 9" deep, the floor of which showed considerable signs of intense heat.
Ovens were probably a fire risk. It was probably this risk, as well as the convenience of having all the baking processes together in a single purpose building, that caused them to be housed separately. However, in Hedeby a house was found with an oven as well as living quarters.
The oven's most important function was to cook bread, but they could also have been used for roasting joints of meat, perhaps coated in a flour and water paste which sealed in the juices. After the bread was baked, ovens could have been utilised for a range of dishes that needed long, slow cooking.
How To Build an Oven
Although there are several methods of building ovens, this article will concentrate on one, the sort we built at Brockhole.
- Cut a piece of turf slightly bigger that the proposed oven including the surrounding walls.
- Build a bed of large flat stones covering an area approximately 2' by 3' which will change according to the required size of the finished oven. Any cracks/gaps in the bed can be filled with clay, which was the local soil in the case of Brockhole.
- The sides of the oven were then built remembering to leave an area for a door, using a dry stone walling technique. Build these sides to the required height of the door. A layer of clay can be smeared around the inside as a mortar/lining/gap-filler.
- The roof on the oven is built in a dome like manner, also using a dry stone "igloo" technique called "corbelling". The igloo should be higher at the back than the front. A small opening (approximately 6 x 3 inches) near the top of the back should be left as a flue (other people may refer to it as an afterburner!). Do not be tempted to have a single large slab as the roof, it will be very prone to cracking and collapsing as occured with the 1991 Brockhole Oven.
- Cover the structure with a thick layer of soil, which will serve as insulation. This should be at least 5" thick over everything. No stones should be jutting out.
- A layer of turf covers the structure. This provides yet another layer of insulation and protects the structure from rain. This obviously wouldn't be needed if the oven is built inside a house.
- Dig a shallow trench from the door to one side of the oven. The end of the trench should have a deeper area which is used to rake hot ash and embers into.
- A large slab is used to close the door of the oven.
- A large fire is built in the oven to dry it out. At this stage you may plug any gaps that smoke escapes though.
How to Use the Oven
- Light a fire in the oven to heat up the structure. Add more fuel as necessary to achieve required temperature.
- When the structure is hot rake out the fire and ash. Make sure that you extinguish any hot embers once in the trench.
- Place the item to be cooked in the oven (not on a metal skillet, as this tends to burn the underside of the item). The items may be placed directly on the floor of the oven, in a clay cooking pot or on a flat stone.
- Leave item until cooked. Don't ask for things like exact cooking times, it's as long as it takes.
Other techniques of oven building all use the same principle, although materials may vary. The oven may be constructed from turf, clay over a wicker frame or dug from a mound.
he oven in the image to the right is built in the more usual style of clay over a wicker frame. This was built in Denmark at the Lejre Folk Historic park near Roskilde in 1994. The structure is the same as the glass kiln built at the same site. All the clay was dug out of a bank by hand from nearby and rendered to rid the clay of any small stones. The frame of the structure was made on a thick clay 'stead', by marking out, and then pushing sharp hazel rods into the ground. Over these rods, a large sausage mix of clay and hay was bound together over the rods to create a thick base to the wall. The intention was to weave a basket like structure over which more clay and hay would be added. However, it soon became clear that as the wall rose, more hazel stakes could be rammed into the clay walls in between previous rods. This is how we continued to create the finished form you can see above. It was fired both inside and out (not the kind of thing you can do inside a building). The base walls were about 6 inches thick, thinning in the roof to about 3 inches. It's external plan was roughly 5 feet long and 4 feet across, rising to 3 feet in the roof. The final fired shape was strong enough for a man to stand on, and for a thin man to get his shoulders through the door and get most of his trunk inside the oven itself. Whilst there, we used it on three separate occasions to cook bread and some meat. Prior to each baking session, we threw some grains into the oven when the fire was raked out, to determine whether the oven was hot enough. If it is, the grain of wheat will burst open with the heat. The door was made from a thick off cut of timber, trimmed to fit the entrance. This was considered to be sacrificial, and not made very elaborately. During the cooking, the door was sometimes plugged with clay if there were too many gaps as it 'died'.
For the winter months, the oven was covered with a thick layer of turves to protect it from water penetration and subsequent frost that would have started its destruction. The oven was still intact in 1999.
Original article by Mark Beadle, 1992
Revised by Roland Williamson, 1999
Illustartions Colin Levick