Wood ovens

Wood-fired ovens

For the last few years I have been experimenting with wood-fired ovens. I have found that they are cheap and easy to build, and fun to use, though they can be unpredictable. They were commonplace before the days of electricity and gas, and they can still be found attached to old houses in rural France, and elsewhere.

An oven can be very simple: just a dome-shaped cavity that can be filled with wood and fired, then used for cooking when the fire has burned out. It could be improvised from an old oil drum, quickly built from clay, or elaborately constructed from fire-proof bricks. You can buy kits, which look rather like ceramic igloos, or ready-made oven domes, either of fired clay or synthetic insulating material.

If it is to work well, the oven dome should be surrounded by heat-retaining material, such as sand, clay, earth, brick or rubble. The more you use, the longer the oven retains its heat, and the more cooking you will be able to do on one firing.

Contents

Construction

The core of my oven is built from kiln bricks, which can be scrounged or bought, as they are often discarded when kilns or furnaces are repaired or re-lined.

The oven’s sole is made of 4 kiln bats (like heatproof paving stones) resting on packed and levelled earth.

The base and dome are built of limestone blocks, with any gaps filled with earth, small stones and rubble.

My oven cost very little to build. The limestone came from my garden, much of it dug up in an attempt to create a vegetable plot. I was given the bricks and bats, and only had to pay for the door, which is steel, and double-skinned. As I am not a skilled bricklayer, I have used a very simple construction method, which has allowed me to rethink the design and correct mistakes. The result is not as elegant or efficient as an antique craftsman-built oven, but it works.

Method

I began by building a dry stone wall enclosing the base, which I then filled with anything that came to hand, ending with earth, which I packed and levelled. A layer of sieved earth made a good base for the 4 kiln bats, which form the floor of the oven.

I then put the first layer of bricks on the bats. They were stood on their ends, in a horseshoe shape, with the opening at the front. I put limestone blocks and rubble around these bricks to hold them in place. The next layer of brick, resting on their sides, overhangs the first, and is topped by another, also overhanging. The idea is to make rough dome shape by stepping the bricks in, using the surrounding rubble to hold everything in place. It is not advisable to go above 3 or 4 courses, or the oven will be too tall (a low dome gives better top heat, which is important for e.g. pizza). The roof of the oven is a kiln bat resting on the top course of bricks. The core should be surrounded by as much earth, sand or rubble as possible, with any obvious gaps filled in.

On the right are some pictures showing the construction of an oven. This one was built by Geo Meadows (www.mecol.co.uk). He is more methodical than me, and remembered to take photographs while he was working. He used kiln bricks and bats for the lining and concrete rubble for the base and dome. His design includes a chimney, which is not usually found in traditional ovens. Because these ovens are shallow inside, the smoke easily escapes through the door.

Note: though the floor of this oven is cemented, the rest of the structure is free-standing, with no mortar used to join the bricks and bats. (Each layer is held in place by weight of the one above it.) This has the advantage that the oven can easily be demolished or rebuilt. I have rebuilt my oven once, because the first version was not quite big enough, and plan to rebuild it again, with improvements.

Fuel & firing

Any kind of wood is suitable, as long as it dry, non-resinous, and untainted by paint, preservative or varnish. I use tree-prunings, DIY offcuts, and proper firewood (e.g. oak or ash logs). My oven takes a level wheelbarrow-load of wood, which is stacked inside the dome, wig-wam style, and lit 3 or 4 hours before it is needed. I leave the door open at first, then close it when the fire has got going. Because of the un-mortared construction, plenty of air gets in.

When the wood has burned down the ashes can be removed, or swept to the sides if the oven is big enough. It is best to check the temperature before putting any food in. If it is too hot, pastry will burst into flames, and meat will scorch in seconds. There are traditional techniques, such as throwing in a handful of flour and noting the colour it goes, but I prefer a thermometer. I have ruined several oven thermometers (of the bi-metal spring and dial type) by subjecting them to temperatures of over 400°C. I now use a non-contact thermometer, which looks like a ray-gun, and remotely detects infrared.

Temperature

This can be hard to determine, as the walls and sole of the oven will be much hotter than the air in the centre. Ovens vary, so experimentation is wise. You need to know the cooling curve for your oven. If it cools rapidly, timing is crucial. The best way to use a wood-fired oven is to cook a sequence of dishes, each requiring a lower temperature. For instance:

· Over 250ºC Pizza (cooks in minutes, directly on the oven’s sole), roasted vegetables (e.g. peppers or aubergines: the skins will blacken & peel very quickly)

· 200-250ºC Meat. It will brown nicely, but may burn if left in too long at this temperature. Sometimes it is best to brown the meat, then put it aside until the oven has cooled a little. However, leave it too long and the oven may have cooled too much. Roast potatoes can be started at this temperature.

· 150-200ºC A good temperature for roasting anything.

· 100-150º Rice pudding, clafouti, baked apples, etc.

· Below 100º As the oven cools it can be used dry fruit (figs, plums, apricots,) or tomatoes. Trays of which can be safely left in the oven overnight.

Cooking

Here are some suggestions:

Pizzas

Pizzas can be cooked directly on the sole of the oven, which should be swept and mopped first. You need a peel (like a giant long-handled bat) to get them in and out. Pizzas cook very quickly (e.g. 5 minutes) so there is little time for topping to melt or crisp. A fresh (e.g. rocket & walnut) or precooked (onion & tomato) topping works well. Unless your oven has a very shallow dome, cheese toppings may not melt.

Small, thick pizzas are easier to handle than large thin ones. They also take longer to cook, giving more time for toppings to melt.

Quiches

These cook well. Try a quiche topped with braised chicory (sliced) and a bit of onion, and smoked salmon. A good first course.

Roasts

Chicken roasted whole or ‘Pollo al forno con patate’. (Adapted from an Antonio Carluccio recipe: Cut a chicken into smallish pieces, arrange them on a roasting tray, surrounded by potatoes, whole cloves of garlic, and small onions (in their skins), garnished with plenty of rosemary, and sprinkled with olive oil. When the chicken & potatoes are crisp and brow, the onions & garlic should be meltingly soft.)

· Goose, whole and stuffed, or cut up like ‘pollo al forno’.

· Duck as goose

· Quails, stuffed or not, arranged on a bed of rosemary

· Kid, forequarter or leg, seared in hot oven, (230ºC), then rubbed with a herb mix, (rosemary, marjoram, thyme, harissa, lemon juice and oil), wrapped in caul if possible, (or Al foil) then returned to oven when it cools to 200ºC

· Lamb, leg or shoulder, rubbed with herbs & garlic, cooked with whole cloves of garlic, which are used to make sauce.

· Belly pork, score skin, put in hot oven (230ºC). Remove when skin is browned, rub in herb & oil mixture. Return to cooler oven (>200ºC) for about 1 hour, surrounded by potatoes & onions. Can be served as a hot dish, but better wrapped in foil and left in overnight. Or, cut off skin and make scratching, then bake the meat slowly in a covered pot, rendering it down. Can be eaten as cold cuts or minced and made into rillettes.

Fish

· Eels, (anguilles aux oignions, or ‘Eel crumble’).

· Sea bass etc. Herbs in cavity, rub with oil and salt, bake until the skin is crisp & brown, and flesh just comes off the bone. (The ‘salt crust’ method described in some books does not work.)

· Sardines, filleted and rolled round stuffing of breadcrumbs, pine nuts, raisins etc. Very good 1st course. Can be eaten cold.

Vegetables etc.

· Stuffed tomatoes good cold the next day

· Oven-dried tomatoes (Cut tomatoes in half, arrange them on a baking tray, cut side up, and sprinkle with salt. Only brief exposure to high temp is advisable. They can go into a cooling oven, and stay in overnight. Store them in jars, with olive oil)

· Roasted vegetable salad, peppers, courgettes, aubergines, fennel, etc.

· Aubergine puree: blacken aubergines in a hot oven, remove skin and mix flesh with yogurt, garlic & oil.

· Baked goats’ cheese salad: bake cheeses briefly on rounds of bread, then serve with green salad and walnuts.

Puddings

· Clafoutis cooks well in cooling oven

· Rice pudding can be left in the cooling oven overnight

· Baked figs, with honey, cream & walnuts, or honey & thyme

· Oven-dried figs, cut in half, spread on tray and leave in cooling oven overnight

· Baked apples, either: stuffed and baked in hottish oven, or put in tray whole and left overnight.

· Quinces, baked in tray whole and left overnight. By the morning they will be soft enough to make an excellent jam which is good eaten with cheese.

Books

Building a wood-fired oven for bread and pizza

is an excellent book by Tom Jaine. It contains plans and instructions for building a rather grand oven (much better than mine) and useful information about baking.

It is available from Prospect Books www.prospectbooks.co.uk

Or from Amazon: