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BU I L D A TR AD I TION A L
WO O D -FI R E D C L AY
OV E N
A Step-by-step guide
1st edition
Simon Brookes
© Simon Brookes 2011
The right of Simon Brookes to be identified as author of this work has been asserted by him in accordance with the
Copyright, Designs and Patents Act 1988.
Visit the blog which accompanies this book:
http://clayoven.wordpress.com
You can purchase extra copies of this book directly from the author:
http://www.clayovenbook.co.uk
Disclaimer: The author will not be held responsible for any loss or injury sustained by any person or persons as a
result of following instructions contained within this eBook.
2
TA BLE O F CON TE NTS
BUILDING A CLAY OVEN – THE BASICS
4
WHAT YOU WILL NEED - MATERIALS AND EQUIPMENT
5
THE BUILD ORDER
5
HOW LONG WILL A CLAY OVEN LAST?
6
THE PLINTH AND BRICK OVEN FLOOR
7
MATERIALS FOR PLINTH CONSTRUCTION
7
PLINTH FOUNDATION CONSTRUCTION
7
PLINTH CONSTRUCTION
7
Plinth Dimensions
7
BRICK OVEN FLOOR CONSTRUCTION
8
Laying the brick oven floor.
9
UPDATE
9
THE CLAY-SAND MIXTURE AND PUDDLING TECHNIQUE
10
WHAT TYPE OF CLAY SHOULD I USE?
10
QUANTITIES
11
MIXING OR PUDDLING
12
THE DOME SAND-FORMER AND FIRST (OVEN) LAYER
14
THE OVEN ENTRANCE AND CHIMNEY
14
CUTTING THE ENTRANCE
16
DRYING THE FIRST LAYER – FIRING THE OVEN
16
BUILDING THE BRICK ARCH
17
THE CHIMNEY
18
THE INSULATION LAYER
19
THE FINAL LAYER
20
FIRING THE OVEN
21
THE BEST PIZZA EVER!
22
THE DOUGH
22
A tip about kneading.
23
TOPPINGS
23
OTHER THINGS YOU’LL NEED (IDEALLY)
23
MAKING THE PIZZAS
23
THE CLAY OVEN BLOG
25
3
B U I L D I N G A C L AY OV E N - T H E
BA S I C S
I assume that most people will already know
what a clay oven is, however it is probably
useful if I define what I mean by a clay oven
for the purpose of this guide. Before I do
that though a quick word about
nomenclature. I will use various names for
the clay oven interchangeably; these include
"clay oven", "traditional clay oven", "wood
fired oven", "pizza oven" and "traditional
bread oven". If you browse around the web
you will also see the name "cob oven" being
The Clay Oven in my garden
used - cob being a mixture of clay and straw
(+ or - sand). As I am not using straw in my build I will not use the term cob but will include it in
my definition, as this type of construction is probably the most ancient of all clay ovens. Another
name commonly used is earth oven.
In my definition then, a clay oven is any hollow, domeThe material for this guide is adapted from
shaped structure constructed out of clay, clay and sand
my original clay oven blog. On the blog
or clay and straw, used for the purpose of baking and
you will find regular updates, video, more
roasting food. It has a brick floor and usually a
photos and also have the ability to post
chimney. Most traditional clay ovens are built outdoors
tips or questions to other blog readers.
and may or may not be covered with a simple roof
You can find the blog at the following web
structure. You will find some amazing examples of clay
address - http://clayoven.wordpress.com
ovens, particularly huge pizza and bread ovens, built
inside restaurants. The oven I have built is much
smaller but still suitable for cooking for large groups of people.
Clay ovens are amazing things. They look incredible and create a feature in any garden, large or
small. The main reason most people want a clay oven of course is for cooking. If you have never
eaten a pizza cooked at 450°C for 1 minute in a clay oven - you have never eaten a pizza! Just
imagine a thin, crispy, slightly charred base covered in hot melted cheese, olive oil, garlic, sun-dried
tomatoes, dried cured sausage, smoked ham, anchovies...do I need to continue? How about loaves
of hot bread cooked to perfection, cracked open and smothered in real butter or a large joint of lamb
or pork belly cooked slowly with herbs over night in the oven's residual heat, falling off the bone
when you come to carve it the next day. I think you get the picture. Cooking in a traditional clay
oven is wonderful; it feels different and definitely tastes different.
Building your own clay oven is not difficult. I am by no means an expert when it comes to DIY but
am normally happy to give things a go. When I built my first oven I had never built anything like it
before but managed to complete it without any major disasters. The beauty of building a clay oven is
that you use mostly natural and, if you are lucky, recycled or free materials. There is something very
primeval about building one of these ovens. In an odd way it feels like a link back to our ancestors
who would have used similar techniques for cooking many millennia ago. I thoroughly enjoyed
building it! It is a very physical and tactile experience - you will handle and form every single piece of
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clay, sand and wood that goes into it and the finished product is something that you will be extremely
proud of.
W H A T YO U W I L L N E E D - M A T E R I A L S A N D E Q U I P M E N T
OK lets crack on with getting this baby built! Here I will list most of the equipment and materials
you are going to need to build your own clay oven. I will provide details such as quantities later on as
I step through the build process.
MATERIALS
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Builders sand
Clay
Water
Rubble / hardcore
Wood shavings
Normal building bricks (e.g. London Bricks) for oven base
Large wooden "beams" or bricks or stone for plinth (I used beams as you will see later)
Cement if you are building plinth out of brick
Right-angled brackets and screws if constructing plinth from wood
Glass bottles (optional)
Old Newspapers
Plastic rubble sacks
Wood for burning in the oven
EQUIPMENT
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Saw (chainsaw?)
Wheelbarrow
Bucket
Tarpaulin or thick plastic sheeting
Shovel
Spirit level
Large knife
Hands and feet!
Wellington boots or other sturdy boots
T H E BU I L D O R D E R
So you have your equipment and materials list. Next I thought it would be useful to outline the
order of construction. This will also form the basis for the rest of the sections in this guide, each
section providing details for each stage in the build process. Simple - I hope! As you might have
guessed already, I love a good list so here goes another:
5
1.
2.
3.
4.
5.
6.
7.
8.
9.
The plinth foundation, plinth and brick oven floor
The clay-sand mixture and puddling technique
The dome sand-former and first layer or the oven layer
The oven entrance and chimney
The wood shavings and clay slip layer or the insulation layer
The final clay-sand layer
Firing the clay oven
Cooking in the clay oven
How Long Does it Take to Build a Clay Oven?
Construction involves quite a few steps and each step takes variable amounts of time to complete.
Probably one of the most time consuming processes is puddling the clay-sand mixture (mixing with
your feet!). One batch (two buckets of sand to one bucket of clay) will take about an hour to an hour
and a half depending on the consistency of the component parts. If you get a group of people to
help then obviously you can speed the process up. Many feet make light work of puddling! Building
the oven layers is also very time consuming and you need to leave drying time between each layer if
possible. The other major factor which affects the length of time it takes to build your oven is the
weather. You can't construct anything other than the plinth if it is raining and it does tend to rain
quite regularly in the UK!
What with interruptions (both weather and non-weather related) from start to finish my oven took 6
weeks to build on my own. However if you have a spell of good weather and a few helping hands
(and feet) I think you could build one in a week.
H OW L O N G W I L L A C L AY OV E N L A S T ?
To be totally honest I have no idea how long it will last. My original garden oven is now three years
old and still going strong (with some care and maintenance!). Some people suggest a couple of years
but obviously this will vary dependent on your location, local temperatures, weather conditions, air
moisture content, the type of cover or shelter your oven is housed in, the amount of use your oven
gets, the type of clay you use for construction and many other factors. They are pretty robust but
they are organic structures and they do crack after repeated heating and cooling. This is not a
problem if cracking only affects the outer layer - you can fill the cracks with spare clay-sand mixture.
However, once you get cracks in the internal oven layer then the oven's days are numbered. I say,
don't worry too much, enjoy it and use it and if it falls apart you can build another one!
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T H E P L I N T H A N D B R I C K OV E N
FLOOR
Your plinth has two main functions. Firstly, it raises your oven to a height that makes it practical to
use. Imagine trying to slide pizzas in and out of the oven on a baker's peel if the entrance is at ankle
level. You would end up with a bad back and a charred mess in the oven! Secondly the top of the
plinth forms the all important brick base to your oven.
M A T E R I A L S F O R P L I N T H C O N S T R U C T I ON
Your choice of materials is dependent on personal taste, availability and budget. If you scour around
the Internet you will find plinths made from natural stone, bricks, cob, wood and earth and wood
alone (like mine). No one solution is better than the other so take your pick. I am going to show
you how to build a simple but beautiful plinth made from wood. I was lucky enough to get hold of
some oak beam off-cuts from a local timber merchant. They are very attractive and very heavy!
P L I N T H F O U N DA T I ON C O N S T R U C T I O N
If you are going to use a construction material with substantial weight from which to build your
plinth and are building on soft ground you will need to establish a foundation first. This is pretty
easy. In my case I dug a 40-50 cm deep hole slightly wider and longer than my intended plinth
dimensions (120 cm x 120 cm) and filled it with hardcore (rubble) to a level just below the top of the
hole. I then topped this off with a layer of builder’s sand and finally laid a paving top onto the sand.
In pursuing the spirit of sustainability, I managed to get hold of some broken slabs which I laid as
crazy paving to form the flat level of my plinth foundation. You can of course use other foundation
methods such as concrete. If you are lucky enough to have a chosen a location with a solid floor on
which to build your oven then you can skip this step.
P L I N T H C O N S T R U C T I ON
So you have a nice flat and solid base it is time to start building the plinth. This is where building
with timber comes into its own because it is just so simple! Before you start building though you
need to think about dimensions and this will involve a little forward planning.
PLINTH DIMENSIONS
The plinth needs to be wide enough (and as your oven is going to be circular I suggest you make the
plinth square) to accommodate all three layers of your oven. The most important measurement is
the diameter of the first layer - the inside of your oven. You need to decide what is practical for your
needs. If you only ever intend to bake pizzas in it then it could be quite small but if you want to use
it to roast legs of lamb or pork joints you need to make the oven layer wide enough in diameter to
accommodate a roasting tin. The internal diameter of my oven layer is 80cm which therefore means
the brick floor on the top of my plinth is also 80cm x 80cm (you wouldn't want any part of the
wooden walls to be inside the oven when you fire it!). Working out from here, each of the 3 layers
should be approximately 7cm thick, so the total thickness of the oven walls will be around 21cm.
7
Add this dimension to each side of your brick
floor width and you will end up with the
correct dimensions for your plinth. Phew! So
my plinth top dimensions are 120cm x 120cm.
Once you have your dimensions sorted,
construction of the plinth is very easy. Simply
cut the timbers to the correct length, not
forgetting to leave enough space for the
overlapping end of each side. Then build the
sides up as if building a wall - overlapping the
lengths of wood to add strength to the
structure. You shouldn't need to use any
"cement" between layers if you are using
heavy timbers like mine. Try to make the top
The plinth dimensions
layer as level as possible as this will help when
trying to level the brick oven floor. I used four internal corner angle brackets on each layer in order
to prevent the structure from moving out of shape.
Your next task is to fill the plinth "box" with rubble (hardcore) to a level of about 30-40 cm below
the top.
After this stage I decided to add a layer of
builder’s sand followed by a layer of glass
bottles (whole with tops removed). My
reason for doing this is that the glass bottles
should provide an extra layer of insulation
and retain heat below the brick floor of the
oven. I have no idea if this actually works
but I had loads of bottles lying around so
thought I'd give it a whirl!
Finally add another layer of sand up to a
depth below the surface of exactly one brick
deep.
Internal structure of the plinth
B R I C K OV E N F L O O R C ON S T RU C T I O N
This is the last stage in construction of your plinth. The brick floor is obviously a critical component
of your oven so I suggest you take your time with this and do it right.
You'll need some bricks, something to cut them with and some more builder’s sand. I used bogstandard London bricks and a hammer and bolster to cut the bricks (although I'm not very good at
this and broke quite a few!). Use any bricks you can get your hands on but try and look for ones with
a nice flat surface, without cracks and avoid any that look too porous. Bricks with hairline cracks will
break when you come to cut them, or worse still, when they are fired in the oven later.
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LAYING THE BRICK OVEN FLOOR.
All you need to do then is fill the top layer of your plinth with bricks. I chose to use a herringbone
pattern which holds together nicely without cement. Remember to try and keep the oven floor as
level as possible.
Once you have laid all of the bricks in place brush handfuls of building sand into any gaps to prevent
any further movement of the bricks.
That's it! Your plinth is complete and ready for the next stage - building the oven!
Constructing the herring bone pattern floor
The finished plinth and oven floor
U P DA T E
If you plan to use wood for building the oven plinth (as above) I recommend a slight modification to
the structure previously presented. It turns out that, over time, the wood at the front of the oven
begins to char and burn (an obvious design fault I hear you say!). The simple remedy to this problem
is to either continue the brick floor along the entire front of the plinth or in a section which will sit
beneath the oven entrance only (as in the modified photograph below.
Modified floor extends beneath the oven entrance
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T H E C L AY- S A N D M I X T U R E A N D
PUDDLING TECHNIQUE
So now the fun begins! Before I get on to detailed instructions of how to build the oven I want to
provide some details on preparing the all important building material - the sand-clay mixture.
INGREDIENTS
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Builders sand
Clay
Water (optional)
EQUIPMENT
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Shovel
Bucket
Tarpaulin
Thick plastic bags
Wheelbarrow
Wellington or other sturdy boots
Legs!
You can buy builders sand from any building suppliers, some garden centres and DIY stores (e.g.
B&Q). Either buy it in individual plastic bags or get a job-lot delivered - you will use quite a lot.
W H A T T Y P E O F C L AY S H OU L D I U S E ?
Without doubt the most common question I get asked at the clay oven blog is about the type of clay
to use. Let’s make one thing perfectly clear upfront - you can use any type of clay you can get
your hands on. For my first oven I dug clay from a local farmer's field here in Hampshire
(overlying Upper Cretaceous chalk if you are geologically minded - possibly Paleogene?). If you
don’t know of a local source of clay you might find information on the internet or maybe you could
ask a local architect or builder. Gardeners are also normally clued-up on the location of clay because
it has such an effect on soil conditions. If you can't find any clay locally you could always buy potters
clay which would be wonderfully homogeneous i.e. free from large particulate matter (stones!).
Which reminds me, try to get clay that does not contain too many stones - they are liable to form the
focus of cracks in your oven if left in the mixture. If you are going to buy potters clay and have
never purchased any before you will soon find out that there a lots of different types; kaolin,
earthenware, stoneware, with grog, without grog - all very confusing. Here’s the rub – buy the
cheapest clay you can. Remember the mantra from above - you can use any type of clay you can get
your hands on.
Finally, some people have been experimenting successfully with powdered clay which, when used in
conjunction with a cement mixer, can dramatically speed up the process of mixing with the sand. I
have not used this yet myself so cannot comment on suitability or volumes required.
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QUA N T I T I E S
You’ll need enough sand for the oven material (clay/sand mixture) and to make the sand former for
the initial dome. The good news is that, after you have finished the first oven layer, the sand which
was used to make the former can be used in subsequent oven layers.
The ratio of clay to sand used to make the oven material is 1:2 (one part clay to two parts sand). I
use a bucket as a convenient measure and found that one bag of builders sand almost filled two
buckets which was nice!
I’m not a great one for recording measurements (sorry!) but readers of the blog have posted the
following volumes for ovens they have constructed:
Comments from the blog
Oven dimensions - 80cm internal diameter, 40cm high.
- 125 – 175kg of clay
- 10.5 – 14 bags of building sand (20 kg each)
- A third to half a bag (100ltr plus size) of wood shavings
The former dome took 120kg of sand to make.
The first layer, chimney and entrance took about 45kg (3.5 bags) of clay and 90kg of sand
The second (insulation) layer took the wood shavings and about 19kg (1.5 bags) of clay.
The final layer and chimney extension (made it a little short to start with) took about 60kg (4.75 bags) of clay and the 120kg of sand used
for the former
Mat (UK)
----------------------------------------------------------------------------I might be wrong, but, if the oven is roughly a spherical shape, then you could calculate the volume of the half sphere formed by the internal part
of the oven (80cm), then calculate the volume of the half sphere formed when the first layer is laid (94cm), and subtract one from the other.
Converting it to liters, you would have an approximate quantity.
I did the math (correctly, I hope – I suck at math), and got the following results (please correct me if I’m wrong):
- First layer – 83 litres
- Second layer – 113 litres
- Third layer – 145 litres
If you’ve got a 10-liter bucket, then my calculations are, at least, approximate. : )
Thiago (Brazil)
I think it is wise to make-up just enough mixture (with a little bit extra) to complete one layer of your
oven at a time. Why? Well if you make up a huge batch (enough to complete your oven) it could dry
out before you get a chance to use it if you get delays between layers (if it rains for example). So how
much do you need for one layer? This will vary depending on the size of your oven. For mine, if we
define one "batch" as two buckets of sand mixed with one bucket of clay, the first (oven) layer took
three batches (6 sand to 3 clay). This left enough over to fill small cracks after drying and to begin
building the chimney. The outer layer required more mixture because it is covered a larger surface
area. I used four and a half batches for this layer.
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MIXING OR PUDDLING
Mixing the clay and sand is by far the most tedious part of the whole build process. What you are
trying to achieve is a well-mixed material with no pockets of unmixed sand or clay and the only way
to do this seems to be by using your feet. The process is known as puddling and it goes like this:
1. Spread a tarpaulin out on a firm
surface (double it over in case you get
holes in it).
2. Tip two buckets of sand in a pile onto
the tarpaulin and spread out a little.
3. Next, fill another bucket with clay.
4. Take a chunk of clay and break it into
small pieces (thumb sized) and
distribute them over the surface of the
sand (like throwing broken-up pieces
of mozzarella onto a pizza base!).
Take this opportunity to dispose of
any stones or sticks you might find in
the clay.
5. Wearing your boots, start to mix the
Clay chunks distributed onto sand ready for puddling
sand using your feet (puddling). The
best technique is to tread and twist. I recommend putting some music on and get into the
groove! Seriously, you will look pretty daft doing this but you need to twist - Chubby
Checker sty-lee! This is where a group of friends come in very handy. Many feet make light
work of puddling sand and clay. It is great exercise though so keep reminding yourself how
much good it is doing you when you start to get knackered and bored!
6. Keep mixing until the clay lumps have disappeared then add more clay chunks and get back
to puddling.
7. Keep repeating this until the bucket of the clay is mixed into the sand.
I found it takes somewhere between 45 minutes to 1 hour to mix one batch. One tip I discovered
which speeds things up is make sure the sand is damp before you start mixing. It definitely helps the
clay mix in better (essentially you are coating sand grains with clay and water helps break down the
clay mineral bonds I assume?). Add some water before hand if you need to but don’t go mad with it!
The last thing you need to do is check that
the mixture is of the correct consistency i.e.
not too wet and not too dry. You might be
surprised at how sandy the mixture seems but
this is how it is meant to be. The drop test
will help you test whether the mixture is
correct consistency or not:
1. Grab a handful of mixture and form
a ball about the size of a lime.
2. Hold your arm directly out in front
of your body at shoulder height.
3. Drop the clay-sand ball onto hard
ground in front of you.
Sand - clay ball after drop test. It held together just right!
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The ball should hold together quite coherently. If it splats flat the mixture is too wet and you should
add more sand to dry it out a little. If the ball breaks to pieces (explodes) it is too dry and you can
add a little water. Simple!
Once you are happy that your mixture is just right shovel it into a thick plastic bag to keep it moist
while you mix the next batch.
If you are ready to start building your first layer I recommend shoveling the final batch into a
wheelbarrow for ease of use. Wheel it over to your plinth - it's time to start building your oven!
Is puddling the only way?
I get asked this question quite regularly and my usual answer is “yes, sorry!”. However, I know of a
few people who have had success using a plaster mixer attached to a drill (the clay has to be much
wetter for this to work though and takes much longer to dry). Cement mixers don’t work usually but
will if you can find powdered clay. Both methods will mean that the ratios of clay:sand will be
different from those I state above but give it a go if you can’t bear the thought of puddling.
Can’t I use clay alone, without the sand?
The simple answer is no. The nerdy answer is as follows. The clay in these ovens does not fire in the
same way that a pot might fire. It never reaches a high enough temperature for the change in
chemical/physical mineralogy that occurs in kiln fired pots to occur. You can view kiln firing as 6
stages:
1. Atmospheric drying (when inter-granular water evaporates from the clay particles). This
normally happens at relatively low temps in a kiln – just over 100 degrees C.
2. Burn off of carbon and sulfur (300-800 degrees C)
3. Chemically bonded water driven off (even after atmospheric water is driven off clay still
contains some 14% chemically bonded water). This only happens at temps. of between 350800 degrees C.
4. Quartz Inversion (silica changes structure)
5. Sintering. Here the oxide minerals fuse to form a ceramic. It is no longer clay at this point.
6. Vitrification
The maximum temperature you can expect wood-fired clay ovens to reach is 350-400 C. So in reality
the clay never gets far beyond stage one – i.e. it is only ever at a state where atmospheric water is
driven off. The outer layers never get any hotter than 70-80 degrees. This is evidenced by the fact
that the clay gets washed away if left to the elements.
My experience has shown that the 2:1 ratio works but as you said it might be possible to get away
with less clay (or more sand). The other limiting factor is how easy the material is to handle and use
when building the dome structures. The clay volume helps keep the material plastic during
construction.
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THE DOME SAND-FORMER AND
FIRST (OVEN) LAYER
Finally it is time to start building your oven.
For this stage you'll need:
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Builders sand
Old newspapers
Water
Tape measure or long steel ruler
Clay-sand mixture
You are going to build a large sand dome - the
former which supports the first clay-sand
layer of your oven. I really enjoyed this part of
Sand dome partly covered with wet newspaper
the process mainly because it provided a
practical justification for the hours I spent
building sandcastles on the beach with my stepson Thom when he was a little lad (to be fair it was
usually me who wanted to build the sandcastles!).
Tip lots of sand onto the brick floor of your oven. I'm not sure how many bags I used but I
remember being amazed at how much was needed to build up the dome to the required dimensions.
Remember the outside of this dome will form the inside dimensions of your finished oven. The base
(widest part) of my oven is the same dimensions as the length and width of the brick floor (80x80
cm). I decided to make the height of my oven approximately half that of the diameter (40-45cm).
Build up the dome, molding and sculpting with your hands until it is the desired height and a nice
shape. A top tip is to keep checking the shape of the dome from above, so periodically stand on
your plinth to get that birds-eye view! Once you are happy with the shape, firm-down the sand with
your hands.
S A N D F O R M E R C OV E R E D W I T H N E W S PA P E R
Next you need to add a layer of wet newspaper. This makes removal of the sand from inside the
cavity much easier later on. It is a little tricky to get the paper to stick but persevere and you'll crack
it. That’s the dome complete. Now you are ready for your first oven layer.
T H E F I R S T ( OV E N ) L A Y E R
If you are doing this alone make sure you leave three or four hours to build your first oven layer. I
made the mistake of starting in the early evening and ended up finishing it at midnight wearing a
head-torch!
Take some of the clay-sand mixture from your wheelbarrow in cupped hands and form it into an
elongated/rounded brick shape. Press this first "brick" against the base of the dome and compress
14
it into place, with one hand holding it against
the sand former while the other makes a
"karate-chop" type movement (using a
straight hand) against the "domeward" side of
the brick. This creates a wedge-shaped "brick"
(sloping towards the dome) which helps when
adding layers above and also removes any air
bubbles from the mixture which may
subsequently expand and crack the oven. You
are aiming for an oven layer that is
approximately 7cm thick and the simplest way
to keep check of this is to measure the bricks
periodically against a marked stick or even a
First few "brick" layers.
piece of straw. Add another "brick" next to
the previous one and, using the same technique, mold it into the first. Repeat the process until you
have laid "bricks" around the whole circumference of the dome.
Begin laying "bricks" on top of this first layer and continue, round and round, up and up, until you
have completely covered the sand dome former. Remember to keep checking the oven layer
thickness as you go. Don't worry if you end up with some variation in thickness - as you build the
oven layer up you might find that the base
widens out a little from the weight of "bricks"
above. Smooth and shape the oven layer into
a neat, coherent shape and don't forget to
check from above.
That's it! Your first layer is complete. You
need to leave it to dry for a few hours before
you cut the hole for the oven entrance but it
does not have to be completely dry. Beware
though, if you used a wetter mix the drying
stage will take significantly longer and is prone
to collapse if not left long enough before the
next stage.
The oven layer dome is complete
Comments from the blog
A handy tip for the natural drying process, if you’ve the time, cover the oven with heavy duty plastic (rip open a manure bag or two). This stops
the moisture from going too quickly and leaves no cracks.
Liam (UK)
15
T H E OV E N E N T R A N C E A N D
CHIMNEY
You have completed your first layer and now you need to build a nice entrance at the front of it in
order to get food in an out (unless you leave it as a dome shaped sculpture!). At this stage we will also
be removing the sand former and build a chimney. You should have left the oven layer to dry for at
least 4 hours before you attempt to cut the oven door but don't leave it so long that the clay-sand
mixture dries too hard or you will find it tricky to cut.
CUTTING THE ENTRANCE
The dimensions of the entrance are
dependent on the dimensions of your oven.
Generally though, you don't want it so big that
it effects the heat retaining potential of your
oven nor too small so you can't get anything
bigger than a tiny pizza through it. In the end
I chose the width of my door based upon the
width of a standard roasting tray and, as it
happens, the width of the bakers peel I had
bought. Don't worry too much about the
height at the moment because you will
probably adjust that later on once you have
fired it.
The oven entrance removed revealing the internal sand former
Roughly mark the width and curve of your oven entrance and then, using nothing other than a
carving knife, slowly cut it out. It will probably come away in large chunks - a very satisfying
experience!
This is the moment of truth! Get yourself a bucket and start to excavate the sand from within the
oven layer. Don't forget to keep the sand for later clay-sand layers. Hopefully you will be able to
excavate the sand until you reach the newspaper layer on the inside of your oven without the dome
collapsing. Take it nice n slow but I'm sure you'll be absolutely fine. Remove as much newspaper as
you can but don't worry too much because it'll burn off anyway the first time you fire the oven.
D RY I N G T H E F I R S T L A Y E R – F I R I N G T H E OV E N
Next you need to dry your oven layer. If you are lucky enough it will dry nicely over a few days in
direct sunlight. However you should also fire the oven at least once to help the drying process but
also to check the entrance is high enough to allow smoke to escape (see below).
The method for firing the oven is quite simple but do bear in mind that at this stage the oven will be
rather damp and does not have a chimney so you might find it takes a little bit of perseverance to get
the fire going. This is how I do it:
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1. Prepare some nice "pencils" of
kindling.
2. Scrunch up five or six pages of
newspaper into balls and form into a
rough pyramid inside but near the
entrance to your oven.
3. Build up kindling around the
newspaper as if building a wigwam.
4. Light the paper and hopefully the
kindling will soon ignite.
5. Watch the fire closely and keep
slowly adding more and more
kindling until it starts to burn well.
6. At this point, using a spade, metal
rake or even a bakers peel, slowly
Kindling burning in the entrance to the oven.
push the fire back a little into the
oven. Don't push it too far because it is likely to go out.
7. Add more wood and when it is burning fiercely move it back some more. Eventually you
want the fire to be burning in the centre-back part of the oven.
A couple of tips here. Firstly, take it slowly. If you try to move things along too quickly you are likely
to extinguish the fire. If it looks like it is going out, screw-up a few balls of newspaper and throw
them in. This is usually enough to re-kindle the blaze. Secondly don't use large chunks of wood smaller pieces burn better.
At this point you can modify the height of the oven entrance if you need to. Look carefully at how
the smoke is moving. If it is "pooling" inside the top of the oven you need to cut your entrance
higher to allow the smoke to escape.
As the oven dries it will steam and might produce a few cracks. Don't panic! Fill in any cracks with
spare sand-clay mixture before you move on.
BU I L D I N G T H E B R I C K A RC H
Now the oven layer is dry you can build the
extension to the entrance. Extending the
oven entrance with bricks not only looks nice
but it also protects the entrance from knocks.
Simply build a sand former in the newly cut
arch of your oven, extending forwards about
one brick length. Place a brick either side of
the former on the top of the plinth using
some of the sand-clay mix as mortar to hold
them in place. Gradually build up the
archway around the former using more of the
"mortar" mix between bricks. You might
have to use quite a lot of "mortar" in order to
produce the correct curve for the arch (as you
Brick arch and chimney complete.
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can see in my photographs below). The last brick should form the keystone of the arch. Leave the
"mortar" to dry a little then remove the sand former. Hey presto - a perfect arch!
THE CHIMNEY
You need to cut a circular hole in the top of
your oven just behind the brick arch entrance.
I sketched a rough circle on the top with a
pencil then drilled holes around the
circumference in order to help with removal
of the now solid "cement". Just tidy the edges
up a little with a knife then build-up a small
chimney around the hole using more sandclay mixture. Finally, close any gaps between
the brick arch, the oven entrance and the
chimney using the remaining sand-clay
mixture.
The brick arch and chimney from the front.
Entrance and Chimney done! Leave it to dry
before we move onto the next stage - the
insulation layer.
Alternative chimney
I have seen old, clay sewage or water pipes used as excellent chimneys on ovens. You will need to
modify the dome of the oven slightly (creating a flat section on which to place the wide flanged end
of the pipe) and cut a hole slightly smaller than the diameter of the pipe in order for this to work.
You can then use clay:sand mixture to “cement” the pipe in place and then build subsequent oven
layers up around it. It is actually very straight forward to do and looks great.
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T H E I N S U L A T I O N L AY E R
Entrance dry? Chimney dry? Great! Let's start building the next layer - the insulation layer.
What you'll need:
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Some clay
Some wood shavings
Some water
A bucket
A wheelbarrow
A spade
A power drill and plaster mixer (optional)
First thing you are going to do is make a clay
slip which is simply clay mixed with water.
The simplest way to do this is to put some
water in a bucket and slowly add chunks of
clay, squashing, squeezing and mixing with
your hands as you go. Alternatively you
could add water to half a bucket of clay and
leave it to soak for a couple of days. You
could then squish-up the clay quite easily.
You are aiming for a consistency similar to
that of thin natural yogurt.
I spent quite a long time making my slip until
The insulation layer complete.
I discovered a short-cut method using a drill
and plaster mixer. It works really well but is
very messy! Chuck your clay and water in a large bucket (or large bin) and blitz it with the mixer. Job
done!
Next throw some wood shavings into a wheelbarrow. I bought a huge bag of wood shavings from a
local pet shop and I still have three-quarters left (any takers?). Add some of the clay slip and mix well
with a spade or get your hands dirty. The mixture should be wet enough to form "bricks" similar to
those you made for the clay-sand layer.
Build up the insulation layer using exactly the same technique as before. Simple! Leave it to dry and
then you can move on to the last step in the build - woo hoo!
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T H E F I N A L L AY E R
The last layer uses the exact same technique as
the first layer so you should be an expert by
now. Using the same proportions, mix a batch
of sand and clay together applying the good
old puddling technique described earlier.
Again, the amount you need depends on the
size of your oven but remember that this last
layer will require more than the first layer due
to the greater surface area you need to cover.
You will also need some spare mix to extend
the chimney (if like me you didn’t make it tall
enough first time round!) and to keep for
filling cracks. Make “bricks” as before and
gradually build-up the final layer. After you
have inserted the last brick, pull-up a chair,
open a cold beer and sit back and admire your
work. Well done, your oven is complete!
The final layer. The oven is complete!
Finished oven from the front.
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F I R I N G T H E OV E N
I discussed the process of firing the oven earlier but I thought it warranted its own section because if
you don’t get this right – you won’t be cooking anything!
This is the way I do it.
1. Prepare a nice big pile of kindling
2. Roll some balls of newspaper and pile
them just inside the mouth of the
oven in a cone shape
3. Pile kindling sticks around the
newspaper like you are constructing a
teepee
4. Light the newspaper and let the fire
catch. Now at this stage I have a
handy cheat that you might find
useful. I have a weed burner which I
bought a few years ago and never
used and it is perfect for getting these
fires going in the oven. It isn’t very
eco-friendly through so I won’t
encourage you to buy one but if you
Burning Kindling in the oven entrance
have one lying around and some
spare gas then go for it!
5. Gradually keep adding kindling to the small fire until it builds to a nice little blaze. At this
stage you can move it a little further back into the oven. I push the fire using a shovel or,
and I find this works well, my bakers peel.
6. The process is then to gradually add more wood (gradually larger pieces) and when roaring,
push it back more until the fire is blazing near the back of the oven. This might take about
60 to 90 mins. Be careful when you are pushing the fire backwards as it has a tendency to go
out. If you find it has died back try adding some small pieces of kindling and blowing
and/or some balls of newspaper.
7. In order to get the oven up to temperature (and I mean so that it is capable of retaining heat,
without a fire burning in it for several hours) you need to keep the fire blazing for at least
another hour. If you intend to cook with a small fire still burning (how I cook pizzas), the
oven will be ready after about now. Check the temperature with your oven thermometer. It
should be nearing 300 degrees centigrade (or more) if you want to cook pizzas.
8. If you intend to remove the embers and use the oven without a fire burning it’s a good idea
to spread the glowing embers across the floor of your oven for 10 minutes before removal.
I then scrape them out with the peel or shovel and dump them into a metal bucket to cool.
Finally a word of warning. If you have any sort of hair on the front of your head and want to keep it
that way WEAR A HAT OR CAP when you fire your oven. You will need to keep looking into the
oven and when it is throwing out 450-500 degrees Centigrade of heat you will singe your hair. You
may not find this as hilarious as my wife did!
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THE BEST PIZZA EVER!
I’m not exaggerating when I say that pizza
cooked in a fiercely hot clay oven is the best
you will ever taste. Why are they better than
pizzas cooked in the gas or electric oven in
your home? It’s all about the heat! The oven
in your home will reach a maximum
temperature of around 250° C. A clay oven,
fired for a few hours, will reach temperatures
well in excess of 400° C and it’s this furnacelike heat that turns a thin circle of dough,
topped with oil, meats and cheese, into an
absolute gourmet treat! Pizzas cooked in a
clay oven take no longer than 2 minutes to
cook. They have thin, crisp and slightly
charred bases while the toppings remain
Pizza cooking in the oven
delicious and full of flavour. Is your mouth
watering yet? Mine is so let’s get on with the main thrust of this chapter which, if you haven’t
guessed already, is about making pizzas in a clay oven.
Firstly, if you want the best pizza ever you really need to buy the best ingredients you can get your
hands on. Make sure you buy good quality flour, organic if possible. Dried yeast is perfectly adequate
so don’t worry about trying to get hold of the fresh stuff. The toppings are crucial too so don’t
scrimp and buy cheap ingredients – you don’t need masses, so splash out and treat yourself to
quality.
THE DOUGH
INGREDIENTS (THIS IS ENOUGH TO MAKE AT LEAST 15 SMALL PIZZAS)
250g strong white bread flour
250g plain flour
350ml warm water (room temperature)
5g dried yeast (10g of fresh)
10g fine salt
A glug of olive oil
Add all of the dry ingredients to a large mixing bowl and give it a quick mix. Next add the water and
mix into a rough dough. Finally add the oil and squidge it well into the dough. Flour a surface and
tip your dough out onto it – it’s time for kneading! You can use a electric mixer with a dough hook
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to do this if you prefer but I like to get working on the dough with my hands – it just seems right
somehow! You will find that this dough is quite wet (sticky) compared to traditional bread dough.
A TIP ABOUT KNEADING.
There are lots of methods you can use for kneading dough but I like to use this one. Hold the dough
ball to the surface of your table with the tips of your left hand. Then with the heel of your right hand
placed in front of the fingers of your left, push the dough forward, stretching it along the surface top
then, in a fluid motion, pull the dough back towards your stationary left hand. Rotate the ball and
repeat. I normally knead for about 10 minutes or so. Lightly oil a large bowl, put the dough into it,
cover with cling film and leave to rise until it is double the original size. That’s it – dough done!
TOP P I N G S
The choice of toppings is totally up to you but here are a few essentials as far as I am concerned:
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A mixture of olive oil, crushed garlic and herbs is, for my money, a much better pizza base
topping than the traditional tomato sauce. Just drizzle or paint it over the surface of the
dough before you add the rest of your toppings – it’s delicious!
Grated cheese (mozzarella, Gruyere, Cheddar)
Chunks of other cheeses (buffalo mozzarella, blue cheese)
Mixed cured meats (spicy sausages like salami and chorizo chopped or sliced, chunks of
good organic ham)
Roasted artichoke hearts
Fresh basil
I would have suggested anchovies to give that powerful salty, fishy blast but unfortunately
anchovies stocks are in crisis due to over fishing so I no longer buy them – I suggest you do
the same for the time being.
OT H E R T H I N G S YO U ’ L L N E E D ( I D E A L LY )
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A rolling pin
A wooden chopping board
A bakers peel (pretty much essential)
A sharp knife
MAKING THE PIZZAS
One of the best things about making pizzas outside using your own clay oven is building your own
pizza – rolling out the dough, selecting various topping mixes from pots of delicious, fresh
ingredients, sliding it onto a peel and finally into the hot oven. It is enormously rewarding and great
fun so I always get everything ready outside then let friends and family make-up their own pizzas as
they go – trust me everyone loves it! The process is simple:
1. Make sure your oven is really hot. I normally fire mine for about 2 hours before cooking.
Leave a fire burning at the rear of the oven and keep feeding this throughout the cooking
period with extra wood. Scrape clear the floor of your oven. I normally push any embers to
the back of my oven using the upside down blade of my bakers peel.
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2. Grab a small piece of dough and roll into a rough ball – about golf ball sized should do. I
prefer to make smallish (maybe 7-8″ diameter) pizzas because they are much easier to handle
in and out of the oven.
3. Flour your rolling surface and rolling pin well but don’t overdo it with flour. You need
enough to stop it from sticking to the surface but too much and it burns on the base of the
pizza once in the oven.
4. Roll the dough out into a very thin disc (mine often come out looking like strange “country”
shapes but it doesn’t matter). Add more flour if it sticks. Critically you want to ensure the
base is NOT sticking to the surface because you will have all sorts of problems getting it
onto your peel once the toppings are on otherwise.
5. Paint or drizzle the base with the olive oil or traditional tomato topping.
6. Throw on your toppings. Hint: don’t pile too much on your pizzas because toppings have a
tendency to fly off when you slide the pizza from the peel into the oven!
7. Slide the pizza onto your bakers peel – I find if you lightly dust it with flour first, then lift
one edge of the pizza and with a quick, fluid movement pull it onto the peel. Practice makes
perfect!
8. Next you need to slide the pizza from the peel onto the hot floor of your oven. Again you
might not get this right the first few times but persist and you’ll have it cracked!. The
technique you need to master is “yanking” the peel from underneath the pizza - very much
like pulling a tablecloth from underneath a fully laid table without breaking the plates or
spilling the drinks! Lightly flour your peel beforehand (not too much though because it will
burn on the pizza base)
9. Let the pizza cook for about a 30 seconds to 1 minute – keeping a close eye on it. I
normally then slide the peel underneath it, take it out of the oven and rotate it through 180°
so that the side that was facing the open oven entrance is now facing the fire burning at the
back of the oven and vice-versa. You might end up with a pizza burnt on one side if you fail
to do this. Pop it back in for a little while longer until you are happy that it looks cooked.
10. Slide the pizza out of the oven onto the peel then transfer onto a wooden chopping board.
Slice and serve.
11. Savor the best pizza ever and feel smug that you have created such a spectacular thing!
12. Repeat until you and your guests can’t move for eating pizza.
Good luck and happy eating!
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T H E C L AY OV E N B L OG
This eBook has been written to accompany The Clay Oven Blog which I have been writing as a
hobby for the last three years or so. The blog is regularly updated with articles and information and is
also a place where you can come and ask myself, and the community, questions relating to your own
project. Since its inception in October 2008 the blog has received over 330,000 visits and inspired
people to build ovens from Honolulu to Helsinki. I also host a gallery of blog visitors' ovens so
please pop by, say hi and share your own story with the community. We'd love to see you.
Have fun building your oven. Best of luck!
Simon [June, 2011]
http://clayoven.wordpress.com
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