The perfect small wood fired pizza oven…
I’ve wanted a wood fired pizza oven of my very own since I was in Rwanda back in 2007. Many pleasant evenings were spent eating delicious pizza made in the roaring hot oven in a little pizza place a stones throw from the Novotel Hotel (now the Umubano Hotel I think) just outside central Kigali. And to be honest there was a healthy logic to eating food which had been heated to around 300C (570f or so), if you understand what I mean…..
However, I was put off by the complexity and size of just about every pizza oven you see built on the internet. Huge concrete foundations, massive concrete and steel reinforced walls and thick heavy bases and even thicker insulation etc. etc. But I only want to cook a few pizzas I lamented, not feed the five thousand!!!!
In the end I decided that good pizza is one of life’s essentials and built one mostly to my own design, cherry picking the bits I liked from others and ignoring the bits I thought were massive overkill. Now don’t forget I am a builder and carpenter, so some of the way I made this might be out of reach for the hobbyist; but I just wanted to show you that a small, simple, wood fired pizza oven is worth building. Trust me, you’ll have fun even with a three sided dry stack of bricks with a concrete slab on top…
How I set about building a small wood fired pizza oven…
Primarily I wanted the pizza oven to be a feature, but not totally dominate our small stone patio at the back of the house. To make it feel light I opted to build the oven on a wooden frame (I know, shock and horror right?). But it was a very sturdy wooden frame to be fair with some internal bracing wires etc.
Building a sturdy base out of timber and insulated concrete…
The oven base I cast onto an elaborate shuttering in an elongated oval shape. I wanted the internal size of the oven to be about 750mm or 30 inches, a good minimum size for two-at-a-time pizza cooking. This slab is a good 15cm (6″) bigger all round to allow for building the dome.
I made my own concrete replacing the stone element with fireproof lecca balls (expanded clay stuff used in plant pots and building insulation). This gave me a lighter concrete with better insulation properties. The concrete slab is 1300mm (4′ 3″) front to back and 950mm (37 3/4″) wide. Basically, I drew two circles with a 350mm (13 3/4″) gap between them to give a ‘pill’ shape or a tube with rounded ends if you like. The mix ratio is 1:2:4 and that’s one part cement, two parts sharp building sand and four parts aggregate (expanded clay balls in this case).
The wooden frame is 100mm (4″) square treated timber very well glued and screwed together. This one is 900mm (3′) by 650mm (25 1/2″) in size and the concrete overhangs by 200mm (8″ on all sides). The internal bracing is steel wire and tensioners screwed into opposing corners. The concrete slab sits straight on top of the framework. This pizza oven must weigh about 300kgs so it needs to be well constructed.
Building a brick dome for a wood fired pizza oven…
The walls or dome of the pizza oven were built using ordinary hard clay bricks (reclaimed from the fireplace in the house) laid in a lime rich mortar (to date no problems have been seen). If mixing your own mortar I’d go for a 1:3 mix which is one part lime putty to 3 parts well sieved sharp building sand. Refractory mortar is recommended but it’s difficult to find here outside of tiny tubs and of course it’s expensive (welcome to Norway!). The first couple of firings spalled a few tiny brick pieces here and there but it’s been stable since then.
Firebricks provide the best base to cook pizza…
For the cooking base I used fire bricks recovered from my fireplace when I switched to a log burner. Once the first few courses of bricks in the dome had set up I cut and laid the firebricks, bedding the bricks on soft sand to make getting future damaged ones out easier, allow for expansion and also to keep a clean look to the outside. I chose to do this inside the dome as I thought building the dome on top of the firebricks silly as the firebricks are only sitting on sand.
Using the trammel to build the rest of the dome was enough to get me quite far up before I chickened out and put in some support for the last few courses. I stuck a small piece of wood to the floor with the hot glue gun and then used a lightly screwed hinge to create the movement needed.
Laying the bricks was easy as the bricks had a good ‘grab’, plus I was tapping them down quite hard to make the front joint as small as possible, virtually nothing really. This makes for a better dome as mostly only the bricks are facing the heat with minimal amount of mortar (which is much softer than the brick). I’ll be honest, I didn’t have the patience to cut each brick perfectly with a disc cutter, as it would have taken days. All my bricks were cut with a brick hammer and dressed a little with a ‘scutch’ hammer, but then don’t forget I’m a bricklayer by trade, so I might have made that look easier than it might be for you…
Finishing the top of the perfect dome…
To support the last few courses I used some old drywall pieces cut to the radius and stacked inside the dome. Drywall is easy to cut to shape, worked fine and was easy to pull out afterwards.
The all important door and chimney configuration…
Building the door and chimney was by far the most difficult bit and I still find it difficult to describe, it’s definitely a make-it-up-as-you-go thing. You know where the hole needs to be and how it works, it’s just difficult to get the bricks to behave at such extreme angles and locations! I used a metal stainless steel 15cm (6″) pipe for the actual flue which you must make sure isn’t cemented in place at any point. Seal the pipe into a pocket left out in the brickwork using fireproof rope found at your local fireplace store. If you cement it in, the brickwork around it will crack because the metal pipe expands…. a lot, much more than you’d think, (go on then, ask me how I know…).
Height of the door and the chimney outlet is 63% of the dome height (opinions vary online, but it looks like 60% to 65% is all feasible). So, ours is 75cm diameter which means a 37.5cm radius and therefore dome height (assuming you’ve made an accurate dome!). This means you need a door height of around 24cm. (30 inch wide/15″ high oven needs a 9 1/2″ tall door or thereabouts). It’s also important that the door sits inside the chimney thus really closing off the air. To be honest I only use the door when firing up the oven (propped on a little block outside the oven) to direct the initial smoke up the flue. And then again when roasting meat or baking bread. You’ll not need a door when cooking pizza. (check here for more… explains the door to dome height ratio)
The hotter the better inside so that means, insulation…
As I was going for a small oven and limited time use, I didn’t go crazy on the insulation. I wrapped the dome with aluminium foil to reflect some heat back into the brickwork and then I wrapped the whole thing in layers of fire blankets (NOTE: If I did it again I would use 25mm or 50mm thick fireproof insulation to better separate the brick dome from the outer rendering to minimise expansion cracking). To hold the fire blankets in place I added a layer of chicken mesh which also helps hugely to hold the first coat of mortar in place on the dome during its application.
Finishing the dome on a wood fired pizza oven outdoors is tricky…
I opted for render over the whole dome, with about 38mm (1 1/2″ or so) of a lime rich mortar. Which, I have to admit was an absolute delight to do. It was actually therapeutic to work on such a perfect dome shape, but I’ll admit wet stuff is my ‘thing’ and I had been missing that kind of work lately, so you might not enjoy it so much.
I put the render on in several coats to make up the thickness. I am still contemplating adding further protection, such as mosaic tiles etc., when time allows. For now, I keep the oven covered with a BBQ cover which I don’t like the look of, but since it’s important to keep the oven dry (to avoid long heating up times and escaping steam problems) I’ll just have to live with it for now.
I loved this bit, so I made this trailer…
Dry out the construction; painful I know, but wait you must…
A wood fired pizza oven gets hot; and I mean really, really hot. So you’ll need to the pizza oven dry out for a few weeks (it really does need a long time) to avoid the problem of moisture boiling inside the masonry and escaping as explosive steam. It took longer than I thought to dry out this one. After a few weeks under an airy cover, start firing the oven with a tiny fire each day for a week and then some bigger ones. I still had some problems with water coming out even after all the care taken above. Slow really is the word here.
Today, there are some small hairline cracks in my dome but hey, who cares. They don’t affect the operation and are just a result of heating the brick dome to over 400 degrees C and not giving it much room to expand (like I said above, I’ll use thicker insulation ‘next time’).
Lessons learned building this particular wood fired pizza oven…
- Loosely cover your newly finished pizza oven, but allow good ventilation to let the construction dry for a long time, weeks if you possibly can.
- Start firing with small fires over several days.
- Make a metal door for the oven and put it in place outside the opening when firing up the oven. Prop it on a block of wood, leaving a gap at the bottom. This will make the smoke go up the chimney aiding air flow.
- Build the fire in the middle of the oven and watch the dome colour. It’ll go from black to clean when the temperature is right.
- Push the fire to the back with a tool or garden rake just before you start cooking and add a few small pieces of wood. This creates the flames you need (licking up and over the dome) to cook the tops of the pizza.
- Before cooking, you can clean the ash from the floor two ways. First you can ‘slap’ your pizza peel onto the floor and this will blast all the ash away. But second and the method I prefer is to use a small natural fiber brush (no nylon bristles for obvious reasons!) screwed to a broom handle. Dip the brush into a bucket of water and sweep the oven floor side to side. The resulting hiss of steam will snuff out the flames, but it will burst back into life (in spectacular fashion) 2 seconds later 🙂
- Sweep the oven floor (in between every few pizzas). Remember to dunk first, if you don’t dunk, the brush will burn. Dunk and shake off any excess water and sweep… quickly!
- You shouldn’t be able to keep your hand inside the oven for much more than ‘one Mississippi’ as they say!
- BIG TIP: if you’re not sure when the oven is ‘hot enough’, look up into the inside of the dome. To start with it will be black and sooty from the fire. Once it really starts to heat up it will burn away the soot, creating a ‘clean’ circle at the top. The hotter the oven gets, the bigger this clean are will expand down the dome. Once it’s about 1/2 way down the dome you’re not far off ready to start cooking.
- Flames should always be licking over the top of the dome as you cook.
- If cooking over a longer period, consider taking a small break and raking the fire back to the the front and build it up a little. Push the fire to the back again before you want to start cooking and don’t forget the small sticks to create flames. (I’ve never needed to do this though cooking for around 12 folks).
- MASSIVE TIP! Use a pinch of course cornmeal on the pizza peel for easy sliding into the oven (really, it’s miraculous), don’t use flour it’s rubbish at sliding pizzas and it just burns on the oven floor.
- Turn the pizza after a minute or less. Turn it two or three times during cooking.
- Rotate the pizza by picking up one side and turning it around with a small pizza turning tool, (like a half size peel). I made one by flattening an old coal shovel from a fireside set and adding a long handle.
- Make the tool handles longer than you’d think, these ovens get really, really hot! Think around the 100cm or 3′ mark as a minimum.
- Make more dough than you think. 100g (4oz) as a minimum and can be closer to 150g (6oz) per person, yup it tastes that good….
- You’ll need more space than you think for preparation, especially when several people are making pizzas. Allow space for at least two people rolling out dough and space for all the toppings.
- Don’t forget to make an ‘after oven’ space for the cooked pizzas, yum.
- A wood fired pizza oven doesn’t have to look perfect, the pizza will taste fabulous just the same…
- Similarly, a pizza coming out of a wood fired pizza oven doesn’t have to look perfect, it’ll taste great just the same lol!
The end result: was it worth it?
I have to say the end result is everything I wanted and much, much more, no problems at all getting the oven up to temperature (takes a couple of hours or so) and it bakes perfect pizza in two minutes or less. It holds the temperature well and even keeps it long enough to roast meat and then cook bread afterwards. Sure, this style of wood fired pizza oven won’t stay hot for three days but we don’t have time for that anyways!
So the lesson learned is, build whatever wood fired pizza oven you can, from whatever materials you have and you’ll have fun, I guarantee it. If it’s a choice between building ‘a poor fellows’ pizza oven or nothing at all, go for the poor fellows pizza oven. And trust me, you don’t need the Taj Mahal of pizza ovens to bake great pizza and have a whole lot of fun doing it.
Good resources for building wood fired pizza ovens…
(p.s. thanks for the help guys, I’d never have got it right without you…)
outdoor pizza oven pompeii
youtube.com/outdoor pompeii oven/
youtube.com/Pompeii Italian Brick Pizza Oven Construction
Digital Laser Thermometers
You’ll definitely need a digital laser thermometer because they are sooooo much fun to play with and of course to impress your guests with the temperature in the oven! I generally get the floor on mine to well over 500 degrees C. (that’s over 900F!). It’s also very useful to teach you about the oven and where it’s hot and where it’s cooler. Also perfect for letting you know when the temperature starts dropping, although the cooking times will also tell you that.
I bought mine from China via AliExpress (Digital laser thermometers at aliexpress) for about £8. Alternatively, you can try, eBay, (Digital thermometers at ebay) or amazon, (Laser thermometers at amazon.co.uk) or here for the rest of the world… (Thermometers at amazon.com. They are useful for finding cold spots around your home too, identifying where you need to work on the insulation…
Awesome Wood Fired Pizza Oven Book
I found this great book this week, written by a couple who run teaching courses on cooking with fire. Learn how to use your new pizza oven properly and it includes many, many brilliant recipes… from Naan bread to desserts! But most importantly it teaches you how to run the oven, from building the fire to managing the heat throughout the cooking time. It opened my eyes to many more possibilities for cooking and getting the most food out of each firing.
As usual, you can buy The Wood-Fired Oven Cookbook from any amazon (it’s by Holly and David Jones).
That’s all folks! Now go and build a wood fired pizza oven of your very own, go on, you know you want to 🙂