Building and Using Your Clay Oven Published by The Good Life Press Ltd. 2010
Copyright ©Mike Rutland All rights reserved. No parts of this publication, including text or illustrations, may be reproduced or stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without prior permission of the publisher, The Good Life Press Ltd. ISBN 978 1 90487 1972 A catalogue record for this book is available from the British Library. Published by The Good Life Press Ltd. The Old Pigsties Clifton Fields Lytham Road Preston PR4 0XG www.goodlifepress.co.uk www.homefarmer.co.uk Cover design by Rachel Gledhill Cover photograph © Simon Brookes Image P.33 © Dave Brock - www.woodtrails.blogspot.com Every attempt has been made to contact the originator of this image. Alterations can be made in the reprint. Printed in the UK by Cromwell Press Group
Contents • Introduction p4-5 • Getting Started P6-7 • Material Selection P8-10 • Making the Base P11-20 • Mixing the Clay P21-31 - the ﬁrst layer P24-26 - building your entrance P27-28 - the insulation layer P29-30 - the second clay la layer P31
• Test Firing P32-41 • Maintaining the Oven P42-44 • Help! It’s Gone Wrong! P45-48 • Recipes P49-89
Introduction Man has been harnessing the power of ﬁre for thousands of years. He captured ﬁre, learnt how to make ﬁre and then learnt how to keep it contained and work for him. We are going to learn through this book how to make, capture and safely contain a ﬁre and how to use it to cook food in a clay oven. Whilst it is nice to have friends pop over on a summer night, have a BBQ and sip wine whilst gathered around a gas patio heater, think how much nicer it would be to have those friends over and cook them dinner in your own hand-made wood ﬁred oven: your oven will certainly become a natural attraction at parties, being a source of warmth, food and discussion. Especially in today’s society where people are conscious of their impact on the environment and lots of buzz words are thrown around such as carbon footprint and carbon neutral, so here you are with a wood-ﬁred oven. Well regardless of hearsay and common perception, once your clay oven is built and in full use you will actually be “carbon neutral” which is more than can be said for a gas ﬁred BBQ and patio heater! You will hear many comments about how bad for the environment burning wood is as you are burning trees. Contrary to popular belief, however, burning wood is actually good for the environment and is starting to become recognised as such. How? Well as a tree grows it absorbs carbon dioxide from the atmosphere, one of the main greenhouse gases. This carbon is then stored safely within the tree and not free in the atmosphere. When the tree is cut down, dried and then burnt the carbon dioxide is released back into the atmosphere, however it can’t release more carbon than it absorbed in its entire life – this is classed as carbon neutral because it doesn’t create extra carbon. If sustainable forestry is used then every time a tree is felled another is planted so the cycle of carbon remains constant and you are having no detrimental eﬀect on the environment. Even better, if you can get hold of timber from a coppiced or pollarded source then you will actually be ‘carbon negative.’ This means you will actually release less carbon into the atmosphere than the tree has absorbed because with these methods of tree maintenance the majority of the tree remains growing and thus still storing carbon.
When you coppice a tree you cut the trunk approximately two feet from the ground. This leaves the root system intact (which contains some of the absorbed carbon) and the tree will then regrow from the base sending up new shoots. Pollarding a tree is a similar system but you leave the trunk of the tree and just remove the branches. The tree then regrows more branches and because the root system is constantly growing and never gets cut, it is constantly absorbing carbon as it grows which is not released when you burn the cut timber. You can’t coppice pine or spruce as the very action of cutting the trunk will kill them, but hard woods such as ash, oak or willow all lend themselves well to this method of management. Coppicing timber is usually done to improve the quality of the tree and preserve it, expanding its life span. It’s not a new technique; they have been coppicing timber for hundreds of years. Our ancestors knew a thing or two about woodland management! I was encouraged to build my ﬁrst wood-ﬁred oven by my wife after she bought me a day’s training in making clay ovens. I have always had a natural aﬃnity with the earth and nature, quite often being found as a child at the bottom of the garden making models in clay dug from the ground or, when older, using ﬂint and steel to create a spark to start a small ﬁre. So imagine my joy as I got to relive my childhood of digging clay, making mud pies and then turning those mud pies in to an oven. We then used the oven to make lunch and bake some bread. So join me in this book to relive your childhood, make some mud pies and reconnect with your primitive side. You can then make some lunch and much much more on your wood-ﬁred oven!
Building and Using Your Brick Oven
The First Layer Now that you have had your well earned sit down, and a sense of feeling has returned to your legs and feet, you will want to get on and build the ﬁrst lift of clay for the oven. Before you rush in there with the clay and make little mud pies or ‘Morph’ look-a-likes, remember that you will need a template to help you form the dome. A dome is the most eﬃcient oven lid as it will allow the heat and smoke to circulate evenly. To form a strong and even dome (the strength is in the uniformity of the dome), it is best to use some kind of former to support the clay whilst it dries. Now, I am no perfect woodworker, so therefore I have made no attempt to form a timber dome shell to build the clay around. I also doubt that I could make a former and then get it out of the clay in one piece as the clay will set around the former so the oven would end up with it lodged inside. So the plan is to make a temporary former that can be removed – enter the damp sand and this sand can be the cheaper sand with grit in as you will be using it as a former only, then discarding it when completed. Place the damp sand onto the oven base and, pretending you are on some glorious sunny beach, form a sand castle dome that sits evenly over the back two thirds of the base. This allows space at the front to build your doorway.
Mixing the Clay So how big should you build your dome? Well, of course this depends on how big you have planned to make your oven, but the size of the sand former overall will be the size of the inside of your oven. On top of this there will be 2 layers of clay, both approximately 50mm (2”) thick and an insulating layer of about 25mm (1”) so you will need the sand former to be a minimum of 150mm (6”) away from the edge of your brick base on the sides and back of your oven base. Whatever the diameter of your dome, you will always require approximately half of that dimension as the height. So for a 1000mm wide base you will want the dome to be around 800 – 850mm in diameter and 400 - 450mm high. Once you have formed the dome in damp sand, cover it with wet sheets of newspaper, and lots of newspaper as this prevents the sand from drying out and losing its structure. It also prevents the clay from sticking to the sand, making it much easier to remove. Keep the paper constantly wet if you are in the sun as otherwise it will dry oﬀ and then ﬂy away. To build the clay skin take a good sized piece of the clay/sand mixture, about the size of an apple, and form it into a small brick shape, approximately 50mm (2”) thick. Place this at the base of the sand dome and press it into place. Take another piece of clay, shape it in exactly the same way and place it next to the Fig 7. Sand former to create the oven space under the clay layer.
Building and Using Your Brick Oven ﬁrst 0ne, smoothing one into the other. Repeat this until you complete a circle all the way around the dome. Now repeat this again above the ﬁrst ring of clay and, as each piece of clay is laid, smooth it into the last piece and into the course below. Ensure at all times that your clay follows the contours of the sand dome. Continue this pattern until the entire sand dome is covered. Once you have made a complete cover over the sand, take a bucket of water and, using your hand or a sponge, use the water in the bucket to smooth the clay to form a nice, clean surface. Give the clay layer a few minutes to dry oﬀ. If in full sun, provide some shade otherwise the clay will dry too quickly and start to crack. Once it’s had a few minutes to stiﬀen, mark the oven door opening using the point of an old knife, trying not to use your wife’s best Viner’s carving knife..... Trust me, it hurts if she ﬁnds out! The door opening needs to be as wide as the largest baking sheet you intend to use within the oven, and the height of the door needs to be about two thirds of the height of the oven. Anything less and the oven will ﬁll with smoke and choke the ﬁre, anything more and you will only have built a nice looking patio heater.
Mixing the Clay Once marked out to your satisfaction, take the knife and cut out the doorway. Return the piece of clay that was once the doorway to the original clay pile as you can recycle it at this point.
Building your entrance You could leave the entrance to the oven as it is, but with use it will get chipped and damaged, so it is best to install a sturdy entrance. This can be done by using some bricks in an arch as shown in the drawing on page 28. To do this, lay a brick level with the doorway entrance, short side up against
the clay wall. Mirror this on the other side of the doorway. Seal and ďŹ ll in any gaps between the walls and the bricks with some clay mixture. This is a lot easier than it sounds. Unless you are an octopus with 8 hands it may pay you to provide support for the bricks as you build the doorway. You can use some more sand as a former or you can use other bricks. This way you can lay the bricks over this former and ďŹ ll in between them with your clay mixture without fear that they are going to fall out and collapse!
Building and Using Your Brick Oven
You have spent a long time thinking about it and considerable time and eﬀort building it, so you might as well cook something in it now! The main attraction for you, especially when you think about wood-ﬁred ovens, may well be the thought of crispy, slightly charred but perfect pizzas, and surely, the wood oven you have just made will be absolutely spot on for that. The fact that the oven can get up to around 400 degrees is perfect for pizzas. Roll them thin, lightly top them with your chosen toppings (my own favourites being chorizo and salami) and throw them in the oven. Give them a minute or two and turn them. After another minute or two they are done! It’s as simple as that. But to get the 400 degree heat you will need to set a ﬁre in the oven for a good couple of hours ﬁrst. That’s a lot of heat being created for just a few minutes cooking and it’s a shame to waste it, so there are many other recipes you can cook both alongside the pizzas or instead of them if you feel like it.
Meat Cookery Remember that you have built an oven. So OK, it doesn’t have a thermostat on it, but to all intents and purposes what you can do in your oven in the kitchen you can do in your oven in the garden. Maybe not souﬄés but certainly roasts etc. should be easy to do. The trick with meat cookery in the clay oven is remembering that you will have an ever decreasing temperature. Therefore the oven lends itself to dishes that require an initial hot sizzle followed by a slow cook. Roast pork, lamb and beef all fall into this category. If you wanted to run the oven for a long period and keep the oven hot, then you could run the ﬁre in the oven along with the food, but you would need to cover the food to stop ash etc. getting onto it, and you wouldn’t be able to run the oven with the door shut as there wouldn’t be enough oxygen getting to the ﬁre to keep it lit. One thing I will insist you need to purchase is a meat thermometer when cooking meat in the oven. This will give you the peace of mind that all is cooked through properly. Eventually you will know from how your oven behaves and how the food looks, but in the early stages it’s nice to have something to back up your initial thoughts. A meat thermometer can be purchased for under £5 at most supermarkets and this is based on the needle and dial with a metal skewer that you stick into the meat. As a general guideline the bacteria that cause food poisoning are killed at around 70 degrees Celsius. So when you probe the food, as long as the temperature reads 70 or more, you know that the food is safe to eat. So let’s start with an adaptation of a British classic – roast beef.
Building and Using Your Brick Oven
Roast Beef rrib of beef, sized according to your familyâ€™s needs oil for brushing salt and pepper
Method Get your oven up to a good cooking heat, just below the pizza temperature. Place your joint of meat in a stout roasting tray and lightly oil and season it with the salt and the pepper. Place the joint of meat into the oven and seal the opening with a wooden door or similar. After about half an hour open the oven door and check the meat. Baste it if necessary and replace it back into the oven. In a conventional oven the rib of beef should take around 25-20 minutes per kilo based on it running at 220 degrees. Initially the oven will be running at 400 degrees so the initial sizzle will take place very quickly, but as the temperature drops the cooking speed will too. Therefore for an average 2 kilo joint you would imagine that the oven will cook it in about an hour and a half to 2 hours. Check the meat after one hour with the temperature probe to see how things are coming along. I can not stress enough that this is an organic method of cooking where many criteria will aďŹ€ect the cooking time. If you need to have a joint of meat out by a certain time for a party or similar, then maybe consider the conventional oven, however, if you like the idea of placing a joint of meat in the oven and standing around in the garden with your friends discussing the rights and wrongs of the world, keeping warm by the oven and periodically poking the meat in a knowing way, then this is right for you. When the meat is done, serve it with seasonal vegetables and a Yorkshire pudding. Although theoretically a Yorkshire pudding can be cooked in this oven, I have had varying successes with it as the door seal is never 100% perfect and the temperature too variable, so it might be best to pre-make a pudding in the conventional oven and then pop it into the clay oven to
Recipes through at the end so that it all comes together. Remember that the meat should not be carved immediately. This is to ensure that the meat stays moist. When a joint of meat cooks the muscle ﬁbres contract, squeezing out the space for the moisture. When you carve it straight away the meat will still be contracted and dry. If you allow the joint to rest for 10 minutes or so it allows the meat to relax and reabsorb that moisture so that when you carve into the meat it is moist and juicy. The retention of moisture is yet another reason why we shouldn’t all get fanatical about fat in meat. The meat should have a good layer of fat, or fat marbling within it. This fat will cook out and as long as you don’t go scraping the pan and eating the fat, it is entirely healthy for you. It not only keeps the food moist during cooking, but it also adds to the ﬂavour.
Lancashire Hotpot You can’t write a book about wood-ﬁred ovens and baking bread and not include a recipe for Lancashire hotpot. If it’s not illegal it should be! The very roots of this dish come from the wood-ﬁred ovens of the bakers in the village. For those that are unaware of the British heritage that is Lancashire, it was swept up in the industrial revolution and produced some of the ﬁnest fabrics and cottons in the world. Most people moved from the villages into the big mill towns to work in the factories. The area was almost as well renowned for its sheep and wool as it was for the cotton brought in from America. So we had a situation where a lot of people had to work long hours and needed to feed themselves quickly as they didn’t have much time and they had a lot of lamb at their disposal. Hence the hotpot was born. The workers would make up the hotpot the night before or in the morning, and on their walk into the mill they would drop oﬀ their casserole pots to the baker who had ﬁnished baking and was letting his oven cool down. He would place these casseroles into his bread oven and when the workers came home at night they would call in at the baker’s and collect their
Building and Using Your Brick Oven casseroles which had cooked to perfection during the day in the cooling bread oven. These days we tend to prepare the hotpot and then cook it straight away, and in a couple of hours it’s done, so it’s not the convenience food it once was, but with the clay oven you have made you can use that latent heat after ﬁring to re-create a real Lancashire hotpot. a tablespoon of rape seed oil 750g lamb, diced into large pieces (mutton really lends itself to the dish) 2 onions sliced 2 carrots cut into large chunks 500ml of stock (lamb or veg) a sprig or two of thyme 750g of potatoes
Method Heat the casserole dish in the oven and add the oil. When hot put in the meat and brown it. Depending on the size of your casserole dish you may need to do this in batches. You may ﬁnd browning the meat easier done on a conventional hob. Now add the onions and carrots to the dish and cook for a further few minutes until the onions are just starting to soften. Return the lamb to the casserole pot and add the thyme and season. Pour over the stock. If using mutton, use vegetable stock as it won’t overpower the dish. If you use lamb stock with the mutton it may taste very ‘lamby’ and this may be oﬀ-putting for some. Slice the potatoes into rings about 5mm thick and arrange them over the surface of the hotpot so that it looks almost reptilian with its ‘scales.’ Put the lid on the casserole and bake it in the oven for an hour and a half, then remove the lid and continue to cook it through for a further hour. Serve with seasonal vegetables and a hunk of bread to mop up the juices.
And Finally..... Having taken the time to build this oven, you have put a lot of yourself into it. You have nurtured it, cared for it when it cracked, cursed at it when you let it burn your pizza, or fell in love with it when you have removed the perfect roast lamb or loaf of bread. It has become part of the family. As such, you may just ďŹ nd yourself calling it by a pet name. Each member of your family can play a part in its construction, adding that personal touch by decorating the base or perhaps with a childâ€™s handprint placed in the wet clay of the top layer or maybe even carve your name into it. By building this oven, you will have created a central feature in your garden that will be much admired and talked about, it will become a gathering point to meet with family and friends who, whilst waiting eagerly for the food to emerge from the hot dome will exchange conversation, debate with each other, ask how things are going or laugh and joke together. Whatever you do, remember the way you built it, the joys and disappointments, learn from them and work that into your next oven, because yes, once you have built one, everyone will want to have a clay oven!
Home made bread, freshly baked and still warm to serve at the BBQ; pizzas served at the kids' parties or even a slow roasted joint of lamb?...