Wood-fired cooking: breads, vegetables and veggie pizzas

A properly fired wood oven is not a rustic version of your kitchen oven. It runs far hotter, it cools down on its own schedule, and it forces you to organise the whole day around it. On a pilot oven measured over several weeks by a team at the University of Naples Federico II, the vault settles at 546 °C and the floor at 453 °C after four to six hours of firing with 3 kg of oak logs per hour (Journal of Food Science, 2022). That is well above the 350 °C figure repeated in most guides, and it changes how you plan a bake.

This article gives measured values rather than recycled approximations, explains what wood combustion actually deposits on your food and into the air, and sets out a way to run pizzas, vegetables and bread off a single firing. It also covers two things the hobby literature almost always skips: carbon monoxide and polycyclic aromatic hydrocarbons.

What a wood-fired oven really does, in numbers

The temperatures it reaches

The published measurements on the Neapolitan pilot oven give solid reference points. At steady state, burning 3 kg of wood per hour, the floor holds at 453 ± 32 °C and the vault at 546 ± 53 °C. Push the feed rate to 9 kg per hour and the floor plateaus around 629 ± 43 °C. Beyond that, adding wood no longer raises the temperature; it mostly feeds the chimney.

The warm-up follows a surprisingly linear rule: the floor gains roughly 49 °C per hour for every kilo of wood burned per hour. At 3 kg/h you climb about 150 °C an hour, at 6 kg/h about 300 °C an hour. That lets you plan a firing in advance instead of standing there watching a thermometer and hoping.

How long firing actually takes

Four to six hours. That is what a masonry oven needs to reach steady state, regardless of how often it has been lit before. An oven fired for one hour is hot on the surface and cold in the mass: the floor will handle the first pizza, then collapse on the second. If you do not have four hours, a wood oven is the wrong tool that day.

Portable ovens with a metal shell and thin refractory panels behave differently. They reach temperature in thirty to sixty minutes, but they store little heat and lose it just as quickly. They suit a run of pizzas; they do not suit a sequence of pizza, then bread, then dessert.

Efficiency, and why you should know the figure

The measured thermal efficiency of the pilot oven was 14.7 %. Nearly 85 % of the wood’s energy leaves through the flue or through the walls. That is not a scandal: well-insulated domestic electric ovens sit between 10 and 15 %, and gas ovens closer to 6 to 7 %. But it does kill the widespread idea that a wood oven is inherently frugal. It is frugal only if you use the whole cooling curve.

Combustion efficiency behaves the same way. At a feed rate of 3 kg per hour, 87 ± 3 % of the wood actually burns; at 9 kg per hour that drops to 79 ± 4 %, with 21 % of the logs ending up as unburnt residue. Loading harder does not cook better. It just makes smoke.

Choosing between a masonry oven and a portable one

The decision turns on thermal mass, not on looks. A masonry oven in refractory brick, with ten centimetres of wall and an insulating slab underneath, stores enough energy to carry a full day of cooking. It is the only type that genuinely supports the sequence described further down. In exchange it demands a base slab, serious construction and real maintenance: an annual check for cracks, protection from damp, and a very gradual first firing after a wet winter, otherwise the bricks can spall.

A portable oven with a metal shell and thin panels costs five to ten times less, stores away and travels. It reaches pizza temperature in thirty to sixty minutes and suits anyone whose main goal is pizza. Do not expect it to bake a loaf an hour after the last pizza; the reserve simply is not there.

There is also a middle path that people rarely consider: a heavy pizza stone or a steel baking plate in a domestic oven set to its maximum, usually 250 to 280 °C. That will not give you a Neapolitan crust, but it costs almost nothing, it works on a weekday evening, and it makes far more sense than firing a masonry oven for two pizzas. Judge honestly how often you will really light a wood oven before building one.

Whichever route you take, two accessories change everything: an infrared thermometer, which costs less than a bag of firewood, and a peel long enough to keep your forearm out of the oven mouth. The rest is optional.

Wood: what matters, and what only looks like it does

Clearing up a common confusion

Plenty of guides contrast “hardwoods (oak, beech)” with “softer woods (poplar, willow)” as if these were separate botanical groups. They are not: oak, beech, poplar and willow are all broadleaves. The real divide runs between broadleaves and conifers, and then, within the broadleaves, between dense and light species.

Dense broadleaves (oak, beech, hornbeam, ash, fruitwoods) burn slowly and leave a usable bed of embers. Light broadleaves (poplar, willow, lime) catch fast, flame nicely and leave almost no embers. They are useful for getting a fire going and useless for holding a firing. Conifers are best avoided in a food oven, less because of any resinous taste than because they foul the flue and burn erratically.

And above all: never treated, painted, varnished, glued or reclaimed wood of unknown origin, and never pallets or particle board. Those materials release compounds you will find again on your food.

Moisture, the most underrated variable

A Czech study published in Toxics in 2025 compared burning dry spruce (12.2 % moisture) against wet spruce (38 to 42 %) across four appliance types. Wet wood consistently produced more particulate matter and more polycyclic aromatic hydrocarbons, and those emissions proved more genotoxic in DNA adduct assays (Toxics, 2025). The mechanism is straightforward: water absorbs energy to evaporate, combustion temperature drops, and burning becomes incomplete.

Aim for 15 to 20 % moisture, which means two years of seasoning for oak and twelve to eighteen months for beech. A moisture meter costs about as much as two loads of firewood and pays for itself. Contrary to what is often written, the storage spot does not need to be bright; it needs to be covered, ventilated, raised off the ground, and the logs need to be split, because bark slows drying.

What combustion emits, and why it matters

A 2025 study measured emission factors from three professional wood-fired pizza ovens burning beech logs and briquettes: 1038 g of carbon monoxide per gigajoule, 157 g of PM2.5, and 1482 mg of polycyclic aromatic hydrocarbons (Environmental Pollution, 2025). The authors point out that these appliances fall outside the regulations covering domestic boilers and stoves, even though their emissions are far from trivial.

In São Paulo, measurements cited by the Naples team recorded up to 6171 µg/m³ of PM2.5 at the pizzeria flue outlet and 68 µg/m³ inside the dining room, against a WHO 24-hour guideline of 15 µg/m³. Globally, WHO attributes 2.9 million deaths in 2021 to household air pollution, including more than 309 000 children under five, and notes that in poorly ventilated dwellings indoor smoke can reach a hundred times acceptable fine particle levels (WHO, household air pollution).

None of this rules out occasional outdoor wood cooking. It does mean three things: install the oven outdoors, away from openings and downwind of your neighbours; burn dry wood in small loads rather than wet wood in big ones; and do not smoke out the house for the pleasure of the flame.

Safety: what can genuinely go wrong

Carbon monoxide

This is the most serious risk and the least obvious. Carbon monoxide is colourless and odourless, and the NHS explicitly lists clay ovens and barbecues used indoors among the sources of domestic poisoning. Symptoms look like flu or a hangover: headache, dizziness, nausea, weakness, tiredness and confusion, shortness of breath. They ease when you go outside and return when you come back in (NHS, carbon monoxide poisoning).

The rules that follow have no exceptions. A wood oven never runs in a garage, an enclosed conservatory, a tent, a shed or under a closed canopy, not even “just to finish the bake”. You never bring a portable oven indoors while it is still hot. You never sleep in a room where embers are still burning down. If several people report the same symptoms at the same time, or a pet seems affected, get everyone into fresh air and call for help.

Burns and fire

The floor of a wood oven sits above 400 °C and shows no visible sign of heat. Household oven gloves are not enough; you need long heat-resistant gauntlets. The peel needs to be long enough that you never put your forearm inside the mouth of the oven. Keep a bucket of water or an extinguisher nearby, a non-combustible surface under the oven mouth, and clear distance from hedges, wooden canopies and garden furniture. Ash stays hot far longer than people expect: store it in a closed metal container, never in a bag or a plastic bin.

Check local rules too. Many Swiss municipalities ban open fires during summer dry spells, and those bans often cover wood ovens and grills.

What wood cooking deposits on the food

Polycyclic aromatic hydrocarbons

PAHs form in incomplete combustion and settle on food surfaces with the smoke. A 2025 study measured the four regulated PAHs on charcoal-grilled vegetables without marinade: from 7.52 µg/kg for onion to 21.79 µg/kg for green pepper (Food Science & Nutrition, 2025).

The encouraging part is that marinades work, and work hard. In the same study, red grape vinegar cut PAH4 formation by 75 % on average, apple cider vinegar by 68 %, lemon juice by 52 %, garlic powder by 34 % and black pepper by 30 %. The effect tracked the phenolic content and antioxidant capacity of each ingredient. In kitchen terms: marinating vegetables for twenty to thirty minutes in an acidic mixture before they go in is not only about flavour.

On the bread side, an Iranian study published in 2026 compared 96 loaves from traditional direct-fired bakeries and from industrial bakeries: the sum of sixteen PAHs came to 68.63 µg/kg against 39.87 µg/kg respectively. Benzo[a]pyrene stayed low, between 0.05 and 0.10 µg/kg, below the EU limit of 1 µg/kg set for cereal-based baby foods, and the probabilistic risk assessment concluded that exposure was acceptable (PLoS ONE, 2026). The point is not to fear wood-fired bread, but to know that direct-flame baking measurably increases contamination, and that clean combustion and ventilation are real levers.

One reassuring detail: heterocyclic amines, the other major family of compounds associated with grilling, form from creatine in muscle tissue. They do not form in meaningful quantities in non-meat foods, as the National Cancer Institute explains (NCI, cooked meats). Vegetarian wood-fired cooking has to deal with PAHs, not with both families.

Acrylamide on starchy foods

Acrylamide forms above 120 °C in starch-rich foods: potatoes, bread, pizza dough, biscuits. The Swiss food safety office classifies it as probably carcinogenic to humans and boils its advice down to one usable phrase, “golden, not charred” (FSVO, acrylamide).

In practice, in a wood oven: pull potatoes and root vegetables when they are golden, not when they are brown in patches; trim the charred edges off a pizza crust instead of eating them “for the grilled flavour”; and store raw potatoes dry, dark and above 8 °C. In the fridge their reducing sugar content rises, which increases acrylamide formation on cooking. It is a pantry detail with a direct effect on what comes out of the oven.

Pizza: the only dish that uses the top of the range

Neapolitan pizza bakes in roughly 90 seconds on a floor around 430 °C under a vault around 485 °C, following the European traditional speciality specification reproduced in the Naples study. That is a very different regime from the “300 to 350 °C for 2 to 4 minutes” repeated everywhere. At the lower temperature, the water in the dough evaporates before the rim can puff, and you get a dry disc rather than an open, airy crust.

A dough that survives the thermal shock

For six 250 g dough balls: 1000 g of type 00 wheat flour (or a strong plain flour), 620 g of water at 16-18 °C, 30 g of fine salt, 1 g of fresh yeast. Dissolve the yeast in the water, add the flour, mix for fifteen to eighteen minutes, rest the mass for twenty minutes, divide into 250 g balls, then prove for 18 hours at 20-22 °C in a closed box. That long, low-yeast fermentation gives an extensible dough that copes with a scorching floor.

Hydration at 62 % is a compromise. Below 58 % the dough tears when you stretch it. Above 68 % it sticks to the peel, and a pizza stuck to the peel over a 430 °C floor is lost in ten seconds.

The bake

Push the embers to one side and keep a lively flame licking the vault. Flour the peel very lightly, top quickly, launch in one decisive movement. After thirty seconds, turn the pizza a quarter turn, then again, then again. The side facing the embers cooks about twice as fast as the far side; without rotation you get one burnt half and one raw half. Total time is 60 to 90 seconds. Our guide to 100% plant-based pizzas at home covers toppings that survive this regime.

Top sparingly. A wet topping releases water faster than the base can drive it off, and the centre stays soggy. A tomato base means 70 to 80 g of purée per pizza, no more. Watery vegetables such as courgette are better pre-cooked, or salted and drained. Cheese goes in with the pizza; rocket, fresh basil and raw oil go on afterwards.

Vegetables: the 200-250 °C window, and the marinade

Roast vegetables belong to the cooling phase, one to two hours after the pizzas. Cut everything to a similar size, around 3 cm, which matters more than the shape. Use a cast iron or earthenware dish rather than the bare floor: direct contact with a 250 °C hearth burns the underside long before the centre is cooked.

A marinade that does the job, for 800 g of vegetables: 3 tablespoons of olive oil, 2 tablespoons of red wine vinegar, 1 crushed garlic clove, 1 teaspoon of chopped rosemary, ½ teaspoon of salt, pepper. Mix and rest for thirty minutes. The acid and phenolic compounds limit PAH formation along the lines described above, and the oil handles heat transfer.

Timings shift as the oven cools. Reckon on 25 to 35 minutes around 220 °C for potato wedges, 20 to 25 minutes for carrots and parsnips in chunks, 12 to 18 minutes for courgette, aubergine and pepper in thick slices, and 10 to 15 minutes for whole mushrooms. Stir once halfway through. If you want to understand why some vegetables brown beautifully and others stay pale, our piece on the secrets of perfect caramelisation goes into the chemistry, and the 10 cooking techniques that enhance vegetables give you alternatives when the oven is cold.

Bread: the 220-250 °C window, and the case for sourdough

Bread goes in late in the cycle, once the floor has dropped back to between 220 and 250 °C. The classic test still works: throw a pinch of flour on the hearth, and it should brown in three to four seconds without catching fire. Sweep the ash carefully, load, close the door and wait. Reckon on 25 to 35 minutes for an 800 g loaf, and trust the core temperature rather than the colour: 96 to 98 °C for a wheat loaf.

Why sourdough is worth the trouble

Beyond flavour, sourdough fermentation degrades phytates, which inhibit the absorption of non-haem iron. A double-isotope absorption study published in Nutrients in 2025 compared two identical wholegrain rye loaves, one made from scalded flour and one sourdough-fermented: iron absorption rose from 7.0 ± 4.1 % to 19.1 ± 15.1 %, roughly 2.8 times higher (Nutrients, 2025).

That result needs reading carefully, though. A 2026 systematic review of eight intervention studies concluded that the acute effects are real but that longer trials did not show improved iron status (Frontiers in Nutrition, 2026). Measuring more iron absorbed from one meal and improving ferritin over six months are different things, and the second has not been demonstrated. Sourdough remains a sound baking choice; it is not a treatment for anaemia.

Our guide to making sourdough starter without a mixer covers getting going, and the protein-rich homemade breads give base recipes that transfer well to a wood oven. For unleavened doughs, the world tour of vegetarian flatbreads offers options that bake straight on the hearth in two minutes.

Running a full bake without relighting

This is where a wood oven genuinely earns its place: one firing, several dishes, each in its own temperature window. Here is a sequence that works, counting from lighting.

Hour 0 to 4: gradual firing at 3 kg of wood per hour. Around the third hour, once the floor approaches 300 °C, toast bread slices at the edge for bruschetta. Hour 4 to 5: pizza regime, floor around 430 °C, embers pushed aside, lively flame. Hour 5 to 6: the flame dies, the floor falls back towards 250 °C, time for bread. Hour 6 to 8: the 200 to 230 °C window for roasted vegetables and gratins. Hour 8 to 10: falling heat between 120 and 180 °C for crumbles, poached fruit, slow-roast tomatoes, drying herbs. The next morning a well-insulated oven is still at 60 to 80 °C, enough to dry tomatoes or apple slices.

That last stage is what makes the whole exercise sensible. Firing a 14.7 %-efficient oven to bake three pizzas and then walking away from it while it is still scorching would be absurd. Working it for ten hours across two or three meals is a different proposition.

Two full meals, with weights

Roast vegetable and ricotta pizza, four portions

One 250 g dough ball per pizza, 70 g of tomato purée per pizza, 100 g of thinly sliced pre-cooked courgette, 80 g of roasted pepper, 100 g of drained mozzarella or a plant-based alternative, 60 g of ricotta spooned on after baking, 1 tablespoon of olive oil, fresh basil, pepper. Stretch, top sparingly, bake for 60 to 90 seconds, turning three times. The ricotta and basil go on as it comes out. Two pizzas make four sensible portions alongside a salad.

Roast vegetable tray, four portions

600 g of potatoes in wedges, 300 g of carrots in chunks, 300 g of squash in cubes, 200 g of onion in quarters, 1 head of garlic halved, the marinade described above, 250 g of cooked drained chickpeas added for the last ten minutes, 60 g of toasted pumpkin seeds, and a sauce of 3 tablespoons of tahini loosened with water and the juice of half a lemon.

For Swiss reference points, one portion of vegetables is 120 g, and the food safety office recommends five portions of fruit and vegetables a day plus one daily portion of a protein-rich food, meaning 60 g of dry pulses or 120 g of tofu (FSVO, recommendations for adults). This tray easily covers three vegetable portions per person and a good share of the protein portion thanks to the chickpeas. Bread counts towards the three daily starch portions, with one portion being 75 to 125 g.

After the bake: leftovers and storage

A wood-fired evening always produces too much food, and the cold chain deserves as much attention as the cooking. The UK food safety guidance is specific and easy to remember: fridge between 0 and 5 °C, freezer around -18 °C, a maximum of four hours out of the fridge during preparation, cooling then chilling within one to two hours, leftovers eaten within 48 hours or frozen (FSA, chilling, freezing and defrosting).

In practice: spread roast vegetables into shallow portions to cool quickly rather than piling them into one deep bowl that stays warm in the middle for hours. Surplus raw pizza dough freezes well as individually oiled and wrapped balls. Bread does not belong in the fridge, where it stales faster: keep a cut loaf wrapped in a cloth at room temperature, and beyond two days slice it and freeze it. Our article on storing fruit, vegetables and pulses properly applies the same logic to the rest of the pantry.

Seven mistakes that come up again and again

Firing for one hour and loading the oven. The refractory mass is not charged, and the floor collapses on the second dish.

Loading the firebox to the roof. Above about 4 kg per hour, combustion efficiency drops and unburnt residue climbs: more smoke, no more usable heat.

Burning wet wood. More particles, more PAHs, less heat. The worst of all three worlds.

Baking pizza at 300 °C because “430 °C burns things”. At 300 °C you need three to four minutes, the dough dries out, and the result is a decent thin tart rather than a Neapolitan pizza. Make that choice if you like, but know what you are doing.

Not turning the pizza. The thermal gradient between the ember side and the back of the oven is enormous.

Bringing a still-hot portable oven under cover. That is the textbook carbon monoxide scenario.

Treating char as flavour. Charred patches concentrate PAHs and acrylamide, and they do not taste good either.

Frequently asked questions

Do I really need four hours of firing every time? For a masonry oven, yes, if you want pizza temperatures and a sequence afterwards. For a thin-walled portable oven, thirty to sixty minutes will do, but you will have no thermal reserve.

Is wood-fired bread better than bread from an electric oven? It is different. A scorching hearth gives a stronger oven spring and a thicker crust, and the oven atmosphere loads the loaf with aromatic compounds from the smoke. Whether that counts as “better” is a matter of taste rather than measurement: published sensory comparisons on this precise point are scarce and depend heavily on conditions.

Is a wood oven environmentally friendly? Not inherently. Wood combustion emits fine particles, carbon monoxide and PAHs in measurable quantities, and WHO ranks air pollution as a major risk factor for noncommunicable disease (WHO, ambient air pollution). Occasional outdoor use with well-seasoned local wood and a brisk fire is defensible. Weekly use with wet wood in a dense neighbourhood is much less so.

Can you cook entirely vegan in a wood oven? Yes, with no technical difficulty. Pizza dough, breads, vegetables, oven-baked pulses and fruit desserts require no animal products. Nutritionally, the Swiss authority notes that a vegan diet requires vitamin B12 supplementation and attention to iodine and zinc, whatever the cooking method (FSVO, vegetarian and vegan diets).

How do I judge the floor temperature without a thermometer? The flour test gives you a range: it blackens instantly above 400 °C, browns in three to four seconds around 250 °C, and takes more than ten seconds below 200 °C. An infrared thermometer is more reliable and costs very little.

What about carbon monoxide in an open outdoor oven? The risk is low in genuinely open air. It becomes real under a closed canopy, in a badly ventilated corner, or if the chimney blows back towards an open patio door. If several guests report unexplained headaches, that is the first hypothesis to rule out.

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