Building a wood fired bread and Pizza Oven - Fabricating the arch supports

It's been a few days since I had chance to work on the wood fired oven project.  The temperatures are forecast to be above zero for a few days, so I had to make progress today.  Even though this is Poland in January, I was able to work all day in just a shirt.  The goal for the day was to fabricate the steel strapping that is designed to prevent the weight of the arch from pushing the supporting brickwork outwards.

Before staring on the steel work, I decided to mock up the soldier bricks that will support the roof dome.  I also rendered the cast lintel with refractory mortar to give the surface a harder wearing outer layer and to fill any voids.  This was a great suggestion made by Terry on The UKWoodFiredOvenForum.  If anyone is planning on building their own oven, would recommend signing up to this forum and discuss you plans with the other members.

Soldier bricks mocked up

For my steel arch strapping, I have chosen to use this 'C' section, I was not entirely sure what size to use, without going into engineering calculations, so instead I used the largest size I could get.  My oven design has a low, parabolic arch which will produce a substantial outward force on the soldier bricks, so it is very important that my strapping is ridged enough.

steel section chosen for bracing arch supports

 The steel frame is first cut to size using a cutting disk on a hand held grinder, then the vertical angle pieces and flat section, lower perimeter pieces and carefully positioned to be in the correct alignment before two small tack welds done on each joint.  The tack welds are small enough to make the frame ridged enough, without pulling the frame out of shape as the weld cools.  My welding skills at beginner level, but I really enjoy doing this bit.

Lower perimeter and vertices tack welded 

 In order to reach the framer on the wall side of the oven, I had to remove the plastic sheet siding.  Once the oven is finished we will build some proper walls.

Welding the oven strapping

 In order to weld the larger arch support pieces in place, which weigh about 60 Kg each, a support block at each end at the correct height made this part of the job very easy.  In this picture you can clearly see the two little tack welds.

Temporary support block while tack welding

 The same technique was used to position the tension strap above the oven door and at the rear of the oven.

Above door tension strap

 Once all the tack welds are in place the frame is already very ridged and has no noticeable flex.

Tack welds completed

 Finally each joint is re-welded with a proper full length weld making sure that the weld penetrates fully to give maximum strength.  With the oven strapping now completed, the next step will be to set the soldier bricks.

Oven strapping now completed

Building a wood fired bread and pizza oven - Lintel now cast, but not without some issues

The lintel has now been cast and cured for 48 hours.  Even after spending hours carefully compressing the layers of refractory into the mold, I am disappointed with the amount of voids, but I do think this this will still be strong enough for the job. I am also a bit concerned that the lintel has very bad abrasion resistance, probably, I did not reach high enough curing temperatures. I have re-covered the lintel now with a heater as I am sure there is still some curing to be done. I will have to find something to treat the surface with to improve the surface durability, probably sodium silicate.  There are a number of treatments that can be sprayed on and soak into the surface before hardening.

The back of the lintel shows the transition from oven to chimney.  This is an important feature designed to ensure a good airflow during firing of the oven.

Building a wood fired bread and pizza oven - Casting the door lintel

Further progress has been made on my wood fired bread and pizza oven.  The supports have now been build that will hold the cast refractory door lintel.  They need to be left overnight to harden enough to position the lintel mold in place.  The shorter brickwork are the reducer arch supports.

Lintel and reducer arch supports

While the mortar in the lintel supports is going off, the mold has been made.  This has been knocked together out of some left over exterior ply.  the inside has been painted with vegetable oil, which will stop too much moisture from being absorbed, prematurely drying out the refractory and will make de-molding easier.

The mold is filled in thin layers, each layer compacted to remove voids.  The thin layers ensure that the matrix of stainless reinforcing fibers are aligned in the plane that will give the most strength benefit to the composite. This is the same technique used and described in more detail in my earlier post Casting the hearth slab.

Filling the mold with refractory

The will be kept like this until tomorrow night when i will de-mold.  I can fee the heat generated by the chemical reaction.

The filled mold hardening

Building a wood fired bread and pizza oven - Hearth completed

My little project to build a wood fired bread and pizza oven is well on the way now.  There is much work still to do before any fires will be lit, but a few late nights with the help of my Dad and we have completed the hearth.  It has not been easy, the irregular shapes and inconsistent sizes of the brick have made job as hard as I thought it was going to be.  

The hearth bricks finished

Next time I build an oven I would sort through all the bricks before starting and pick out the most consistent sizes and undamaged ones.  There are a few locations on the hearth where there are local height changes due to some deformed bricks.  Before the brick dome is built the hearth will be smoothed with a diamond grinder to make it as flat as possible.

The next step will be to cast the over-door lintel on its brick supports.  This will be done in place as it will fit better that way.  Then the steel braising will be welded to fit what has been built so far.

Spiced Christmas Sweet Buns.

Yesterday I baked some sweet buns. This uses my general purpose sweet bun dough that I use to make a range of different treats like hot cross buns, Chelsea buns and tea cakes.  This time I am made a sort of Christmas spiced rolled bun.  In describing this dough, I have tried to be as exact as I can, but this is one of those dough recipes where I never way anything out, its all done by eye and feel.

I start by making a pre-ferment the day before I want to bake using half of the flour that I want to use in my final dough, in this case, it was about 250 g of flow and my final dough would contain approx 500 g of flour.  The flour I have used is standard Polish wheat flour, type 650, it is not a strong bread making flour as it is not available locally.  I have discussed this in more detail in my post Bread Making with Polish Flour.  To the flour I have added about 250 ml of cold water and 4 g of instant yeast.  This is not very much yeast for this quantity of enriched dough and if you wanted to make buns within 3-4 hours, you would have to use significantly more, but as I am going to allow the yeast to have a long fermentation, this will give the yeast plenty of time to multiply into a much larger active culture.  The long fermentation of the flour by the yeast will produce byproducts that will bring a far better flavor to the dough compared to using lots of yeast and short fermentation, which will give you the carbon dioxide you need for a rise, but no flavor.  The first 3 hours of fermentation was done at low room temperature to get things moving, approx 19°C and then left overnight at a around 10°C.

The next day I loosen the pre-ferment with 250 ml of milk and beat in one egg.  I then mix a teaspoon of salt in with 250 g more flour and then mix in my pre-ferment.  80 g of melted butter is mixed in and the whole mixture left to rest for ten minutes.  The result is a sticky dough that I knead using a dough scraper in one hand and ether flour or water on my other hand, depending if I want to adjust the dough to be wetter or dryer.  The dough is then left for another fermentation at room temperature for 2-3 hours.  During this time I will gently de-gas once to prevent the dough from over stretching.

After fermentation the dough is tipped out onto a floured board and gently stretched into a long thin rectangle.  The Dough is lovely to tough at this point, is is super light, soft and silky.  If is does not want to stretch far enough, I like my dough to be no more than about 4-5mm thick, then wait a few minuted between stretches for it is relax.

Portioning sweet buns in our temporary kitchen

While the dough was fermenting a mixture of butter, dark brown sugar, cream and  some flour to stabilise it all was blended together.  This mixture is spread of the dough and a blend of cinnamon, nutmeg, cloves and mace, sifted over the surface.  I have used whole spices grown down in a pestle and mortar.  The dough is then rolled up.  I use this opportunity to further stretch the dough to make each layer even thinner.  The roll is then cut into slices with a dough scraper and placed on a baking tray. 

 Baking was done in a fan assisted oven at approx 170-180°C until lightly browned, turning once for a more even bake.

The first piece of our concrete counter tops just brought up to what will be our kitchen, with the sweet buns and the spices used.

Resisting the amazing smells long enough to take a few picture for the blog gives the buns just enough time to cool down.  I'm so happy with the first piece of concrete counter top to be finished that I had to use is as a background for this image.

Left over bread - Warming winter tomato soup recipe

If you have some left over bread, it's winter and your immune system needs a bit of a boost, My winter tomato soup recipe is just what you need .  Its really easy to make, takes very little time, one of the cheapest meals I know.  I used to make this recipe a lot as a student, and had not make it in many years until the other day when I was wondering what I can make from the large amounts left over from experimenting with a focaccia recipe.

You want to use a bread that is going to hold together, focaccia, ciabatta or a good sourdough are best, but you could use a slightly stale ordinary commercial bread.

This recipe can use tomatoes that you have preserved from the summer, or can use a combination of tinned and fresh tomatoes.  There are some very good quality tinned tomatoes available which will produce great results.  Here is what I used this time, because is was already in the house;

Makes about 4 portions

3 medium sized onions
400 ml of tomato passata (could substitute for 2 tine of tomatoes)
a handful of cherry tomatoes
one hole bulb of garlic
approx 500 ml lamb stock (also works with just water or stock cube)
salt and pepper
olive oil
sprigs of dried thyme
left over Focacca (or other rustic bread)


Finley chop the onions and soften in a olive oil, be very generous with the olive oil.  Chop and add the garlic, passata, season with lots black pepper, throw in a few branches of dried thyme and stock, leave to simmer for 15 - 60 minutes depending on how much time you have.  After simmering you can pull the twigs of thyme out, the good bits, the little leaves will have fallen off.  Put your fresh tomato into the pot and simmer for a few more minutes so that they are beginning to cook, this is a good time to finish seasoning with salt and more pepper. Cut the focaccia or other bread into cubes, approx 2 cm is a good size, then gently mix.  Most of the liquid will will be absorbed by the bread leaving a really thick soup.  After a couple of minutes sitting off the heat, the soup is ready to server.

Server on its own or topped with a spoon of sour cream or maybe some Parmesan.  This Soup is guaranteed to make you feel better on a cold winter day.

Building a wood fired oven - laying the hearth bricks

After a hard days work, it was time to unwind by laying a few of the hearth bricks for my wood fired oven.  It's not exactly the best time of year to be doing this, it is definitely winter here in Poland, dark by 4 PM and about -5 °C by then.

The mortar I will be using I have made by soaking some clay, dug from our garden, in water all day.  I turned the clay/water mixture a couple of time during the day and by evening it had soaked up lots of water.  

At first I though I would mix the clay smooth with a stick, but this soon proved very hard work, so I switched to a pain mixing attachment in a power drill.  To the clay, I then added an equal quantity of fine quarts sand and mixed for a few more minutes until smooth.  The result a very nice consistency of very sticky adobe mortar, minus the plant fibers.

To enable me to position my first brick correctly, first measured where the center of the hearth would be positioning a brick at the far end of the oven so that I could line up my first brick by siting down one edge lie a gun site.  Once this brick was strait and level the bricks on ether side were laid.

lining up the first brick

I'm trying to use a thin layer of the mortar and to enable me to adjust the brick as I set it, I am using a serated trowel to lay  ridges of mortar, much like you would do if you were laying tiles.  the bricks are placed with no mortar between them and and a tight together and as level as possible.  This was very slow going as the bricks are not very consistent in size or shape many do not have strait edges and have be rejected for use in a less critical part of the oven.

I think the first five bricks here have taken me more than an hour, but I'm not really worried how long this takes as long as its right.  These are the first few bricks I have ever laid, so at this point I'm hoping that I'll get better at it and things will start to move a little faster.  After about 20 bricks I'm starting to work out a few tricks, better at judging the amount or mortar, and better at tapping the brick in the correct position to steer it in the direction I want it to move.

Its getting very cold by this time, a quick cup of tea, and a few more bricks and I'm ready to pack it in for the night.

Two rows down, 4 more full rows and the ones around the ash slot.  A few more hours work and the hearth bricks will be laid.