Bakery oven seminar

by admin on 23/04/2009

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Slow Food Oslo together with the Society for the Preservation of Norwegian Ancient Monuments (Fortidsminneforeningen), the Foundation Bogstad farm and Kompetansenettverket, a public organization for aiding small-scale food producers arranged a bakery oven seminar at Bogstad farm on Thursday 23 April.

The person who initiated the seminar was Elsa “Sprossa” Rønnevig and in addition, the following persons held speeches:

  • Hotel director and cook Harald Olav Lie-Nilsen
  • Mason Espen Martinsen
  • Baker Øyvind Lofthus, Åpent bakeri (Open bakery)
  • Norwegian champion in cooking, Trond Moi, Bølgen & Moi
  • Architect Ole Christian Torkildsen
  • Baker Erik Olofson, Sweden

The seminar was opened by Elisabeth Seip who told us that the bakery oven was built in the 1760s and is still located in the same house in which it was built. Bogstad farm was privately owned for about 200 years until 1955 when the sisters Egeberg donated the farm to the municipality of Oslo provided that it should still be driven as a farm.

History of the bakery ovens

Harald Olav Lie-Nielsen went back to the origin of the bread about 9,000 years ago before turning to the Romans. After having conquered Greece, the Romans brought Greek bakers to Rome and they also taught the Romans how to bake. Thereafter, the art of baking has been passed down generations up to our times.

Since grains are best conserved as grains, while flour will turn inedible after a short time, our ancestors began to make flat bread in the 1300s for the simple reason that it doesn’t mould, while rich people imported wheat, malt and honey from Great Britain.
The bakery ovens are dependent on an abundant access to wheat and rye which led to that the bakery ovens were located mainly along the coast, while making of flat bread was continued inland. Besides, an abundant source of fuel has to be available, which consisted mostly of spruce in Norway.

The bakery ovens were constructed in houses where heating was necessary for activities like brewing beer, making liquors, slaughtering animals, washing clothes and moulding candles.

The cast iron oven arrived around 1850 where many breads could be baked at the same time, but the bakery ovens were still in use until about 1945.

As leavening agents were used yeast, sourdough starters and enzymes from calves’ stomachs where yeast has been used for the longest time.

Contruction of bakery ovens has been based on local traditions and materials.

Problems and joys in connection with bakery ovens

Else Rønnevig decided to use the bakery oven as a means to increase interest and respect for our building heritage in 1987. Then, she got restored an old bakery oven which had been used for ages by her grandmother. One of her childhood memories was when they fired the oven with heather which they collected and let stay outside when the frosts arrived having the fortunate consequence that the roots broke off.

Restoration of the bakery oven was far from easy, among other things, an iron door to open and close the oven. She called the iron works at Ulefoss in order to order one, but was instead told that they hadn’t been produced for about 60 years. In the end, she got one door made at a local workshop in Arendal. Thereafter, the iron works at Ulefoss has restarted their production of iron doors, but in small quantities only. The grandmother of Ms Rønnevig used a wooden door which was made wet just before another baking should start.

In order to pay for the restoration, Ms. Rønnevig cycled around the town of Lillesand with homemade bread priced at 60 Norwegian krones each!

Small and big bakery ovens have been built in Norway for several hundred years. None of them were equal and no drawings were made. Instead, the building of bakery ovens were passed on from generation to generation. For each oven which was built, available space, the number of breads which could be baked at the same time in addition to the craftsman’s knowledge and capabilities decided the resulting oven.

Those who are interested in baking bread in a traditional oven, can join a course run by Ms. Rønnevig.

She also mentioned decoration of bread which originated with the Hanseatics in Bergen.

Experience with restoring old bakery ovens

Espen Martinsen is master mason, who restores old bakery ovens. Before restoration can start, the bakery oven has to be documented. This consists of photographing and registering the present state of the oven in addition to disassemble it in order to see how it has been made. Restoration of an oven will always be a cooperation between the owner, the craftsman and local authorizing authority, normally the local master chimney sweeper.

Building and restoration of bakery ovens is mainly done with local materials, that is, clay and lime mortar in addition to bricks and stones. Lime mortar isn’t so hard and strong as cement mortar, but its advantages makes it invaluable in a bakery oven because it releases strains in the oven. The strains arise when the oven is warmed up and the materials in the oven expand at different rates with temperature. While concrete will not give way, the lime mortar will, leading to that the different expansions of the materials in the oven will be released. Instead, using concrete, the strains won’t be released and cracks will arise.

Another building material which is widely used is clay. Clay originates either from sediments in lakes or from moraines. In order to find the right type of clay, Mr Martinsen cooperates with the Geological Survey of Norway. Thus, using local clay and stones, all or most of the oven consists of local materials.

In addition to lime mortar and clay, bricks are also used. Based on years of trial and error, it has been found that weakly burnt bricks should be used in the lower part of the heating chamber, while strongly burnt ones may be used in the upper part of the same chamber.

Principles for building of bakery ovens, fire regulations, etc.

Ole Chr Torkildsen works as an architect, but he also has a versatile experience as a carpenter restoring old wooden houses. He has demolished many bakery ovens in order to see how they are built. A bakery oven should at least consist of the following:

  • smoke channel
  • heating chamber
  • cast iron door

and it should be constructed by means of bricks and stones. The bricks should be used in the heating chamber, while stones may be used for the rest of the oven. Iron should be used as little as possible because it expands much more with increasing temperature than the other materials of the oven. The door is an exception since this will be hinged and not work against the other materials.

The fire regulations are from 1924 which are based on a description on bakery ovens made by agricultural engineer Tandberg in 1885.

Open bakery

After the speeches we were invited downstairs to have a look at the bakery oven. We were met by Øyvind and Andre from Open bakery, who showed us baking of sourdough and yeast dough bread. The dough was made at a bakery called Samson in advance.

We also got a demonstration of how to measure the temperature of the oven. Throw some flour into the oven and measure the time it takes to be burnt. If it gets burnt after less than 20 seconds, the oven is too hot. They are only using dry spruce to heat the oven at Bogstad farm. Pine contains too much tar to be used, while oak contains too much tannic acid.

After heating, but before baking, the ash and the embers had to be removed. This was done by raking followed by brushing. Judging by the taste and the look of the breads, it seemed like the cleaning of the oven was done well.

The bakers from Åpent bakeri demonstrated breadmaking of the yeast dough by forming big “doughnuts”, which they put in baskets specially made for keeping the shape intact. The sourdough was originally in a big trough before they poured it onto a table. Then, they cut it into small pieces, forming buns and putting them in other types of baskets. Unfortunately, we didn’t have time to see the breads being put in the oven and being taken out again after baking.

After having eaten a delicious lunch consisting of, among other things, the newly baked breads, the seminar continued. Then, we were informed that the state doesn’t support restoration of old bakery ovens nor support education of masons who can restore them.

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