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Wood furnace "Grannus”
Cooking in the open air with the Baking Temple by BRUNNER
Find now a furnace builder

Grannus

The wood furnace for the garden

Thermal concrete optics

As the name suggests, a wood furnace is heated with wood as a fuel. Traditionally, it is made of bricks, as in grandmother's time, and stands weatherproof in the garden or, in the case of farmhouses, in the protected courtyard. It is a real building that cannot be moved later on and is therefore a lifetime purchase. Bricks or clay are usually used for the construction and refractory concrete, firebrick or bricks for the outside cladding. 

It is unusual to connect an electric furnace in an open-air kitchen. Instead, you can install a brick furnace. With its GRANNUS, the Lower Bavarian premium manufacturer BRUNNER offers an entire wood-heated baking house, also called a "baking temple". Here, every pizza, every tarte flambée turns out perfectly, as does homemade bread or a tender roast. However, cooking and baking in the open-air kitchen requires some lead time. Only after two to three hours and just as many burn-offs will the kitchen reach temperatures of around 500 degrees. The firebricks ensure that the heat is stored for a long time and is released evenly and slowly. Cleaning the GRANNUS is child's play; the white ash, which no longer contains any charcoal, simply needs to be swept out from time to time and not necessarily after every baking or cooking process. 

System baking oven
Grannus

Wood furnace for outdoors

How to cook with the Grannus

Baking your own bread is in vogue. Not only cakes and pastries, but especially fresh breads, pizza or tarte flambée. And when coming out of a traditional wood furnace, these dishes taste even better.

What goes into the wood furnace first depends on the required temperature.

  • The hottest temperature level 1 is ideal for pizza. The wood fire acts like a side burner, the heating gases rise to the top creating an intense top heat. Pizza or tarte flambée are ready after just one or two minutes.  
  • Step 2 is suitable for all meat dishes, but the Grannus must first cool down to about 270 to 250 degrees. With the cast-iron GUSSTO roasters, pans and saucepans by BRUNNER, any roast can be cooked easily. 
  • Breads are baked at level 3 from around 220 degrees. The right temperature is determined in this way: Sprinkle a little flour on the bottom of your oven at intervals. If it turns black and chars, it is still too hot. Only when the flour is just browning should you put the loaves in the oven for 50 minutes. 

Discover more furnaces for cooking, grilling, roasting

With the power of wood fire: the traditional way to bake a crispy pizza, a tarte flambée or bread. But with a BRUNNER wood furnace, you not only get aromatic baked goods, but also large pieces of meat, such as a juicy roast, can be prepared with it. Thanks to the even heat, optimal cooking and baking results are achieved. Whether as a Grannus baking temple or as a Fire Igloo with a self-built oven casing - the outdoor furnace will be the centre of the garden and is a purchase for life.

1
Pizza igloo
The customisable fire igloo
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1
Kitchen fireplaces
Cooking like back then with the Urfeuer®
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IRON DOG N°06
Wood stove with hob and grille
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Setup
Development
Heat storing concrete cover with shadow gap
Base foot
Stoking door insulated
Thermometer 50-100 °C top and bottom heat
Cover plate for outdoor area, powder-coated, anthracite with microstructure
Handle top panel
Exhaust pipe (on site)
Adapter for exhaust pipe (ø 180 mm)
Vault
Storage rock (MMS-Olivine)
Floor stone consisting of chamotte
Plating for storage rocks with insulating air gap
Hohlraum wird mit Dämmschüttung verfüllt (bauseits)
Grannus

In modern thermal concrete cladding

To light the stove, place firewood, chopped as small as possible, on crumpled newspaper and light it - then add larger logs. The stove dome turns black at the beginning, but when the right heat has been reached, this accumulated soot burns off again. To increase the temperature further, close the door as soon as there are only embers left. It takes about 2-3 firings with max. 7 kg of firewood each to reach the right temperature.

Pizza, vegetables or meat are prepared first - bread comes last, as the residual embers and ashes have to be cleared out of the oven for this. In this way, the heat can be used optimally. For longer baking times, it is advisable to use the fireclay insert to separate the baked food from the embers.

Functioning

Functioning of the classic wood stove

The wood stove consists of a brick cavity, which often has the shape of a vault or a clay dome, hence the name dome stove. This cavity has a chimney flue at the top and an opening at the front. The fire is lit in the cavity, which heats up the entire masonry. This is called direct firing. Alternatively, there are systems with a separate firing chamber. A special wood furnace thermometer indicates the temperature; it can withstand heat up to 500 degrees Celsius. Once the wood stove is hot enough - the initial heat is around 320 degrees - and the wood and embers have burnt down, the baking chamber is cleared out. It should then be left to stand for a quarter of an hour, which allows the heat to spread evenly in the oven. Put the bread, pizza or tarte flambée in the oven. In this wood stove, it receives strong but slowly decreasing heat or radiant heat from each side and, through the precipitation of the wood fire, the typical, unmistakable aroma. After four to five hours, a wood stove still has a heat of around 180 degrees. Reheating is not necessary.

Indirect burn-off

In a wood stove that is indirectly fired, the baking chamber and the combustion chamber are separate, so the appliance consists of two chambers that lie on top of each other. This has both advantages and disadvantages. One advantage of a wood stove with indirect firing is that the fuel does not have to be removed for baking and cooking. In addition, neither smoke nor flames can reach the food being baked. On the other hand, this type of wood furnace takes a long time to heat up, or the heat takes longer because it first has to spread from the firebox into the cooking chamber. 

Grannus

A BRUNNER kit with a system

The Grannus is a wood-heated bakehouse, the shape modern and simple. But the grey block cube houses everything it takes to bake bread, pizza and tarte flambée. Juicy roast meats are also perfectly prepared. And with all the power of the wood fire. The elements of the baking vault are cast precisely from fire concrete. They are dry-assembled on the base plate. The vault bricks and vault components are held in place by the interlocking tongue and groove system. The construction is easy and can be implemented quickly. The hollow structures around the fire igloo - which can also be erected separately - are filled with an appropriate insulating fill. All components are designed for domestic use.

To light the stove, place finely chopped firewood on crumpled newspaper and light it, then add larger logs. The stove dome will turn black at the beginning, this is normal. As soon as the right heat is reached, this soot burns off again. Do not close the door until there are only embers left, this way you can increase the temperature even more. After two to three burn-offs and a maximum of seven kilograms of wood, the Grannus is hot enough. Grannus and Fire Igloo guarantee culinary enjoyment in the open air.

Building the wood stove yourself

A rustic wood furnace in the garden is the dream of many home-owners, whether as a pizza oven, for preparing crusty wood stove bread or a juicy roast. If you want to build it yourself, you need a lot of craftsmanship, a kit including building instructions makes the work easier.

When the temperatures climb in spring at the latest, the barbecue season begins for many. Sitting outside with family or friends and enjoying delicacies such as sausages, steak or vegetables over a wood fire. If you are the proud owner of a wood furnace, you can serve up even more delicacies. He can use it as a bread oven or pizza oven, he can prepare tarte flambée, juicy roast meat, crispy roast pork or various casseroles. Such a brick stove can either be built completely by yourself according to instructions or a picture, which makes it unique in any case, but also requires craftsmanship. Alternatively, many manufacturers offer very good kits or you can buy a completely finished wood stove for cooking and baking outdoors.

What should be the size?

Depending on what is to be prepared in the wood-burning oven, what is to be baked, cooked or roasted, the size of the baking surface varies. A pizza, a tarte flambée or a loaf of bread can be prepared wonderfully on a baking surface of 30 by 30 centimetres.  If the baking surface is twice as large, namely 60 by 60 centimetres, there is enough space for four pizzas or tarte flambée or four to six loaves of bread. You can also comfortably accommodate several roasters, Roman pots or pans. 

To consider

Permits are required for a brick stove in the garden or yard, because it is a "stationary" object that is not removed in phases, for example in winter. If you cannot remove your wood stove at any time, you do not need a permit because the installation is not covered by the building regulations. However, neighbouring law prescribes consideration. If you build a small house around your wood stove, for example as a weather shelter, this may require both a building permit and regular maintenance by the chimney sweep. If you want to build without a permit, you must keep a distance of three metres from the neighbour's boundary and/or from public areas. In addition, the furnace must not exceed a certain volume and maximum height. The limits vary from federal state to federal state. Information can be obtained from the district chimney sweep or the local building authority. If you are renting, you should also inform the owner of the house or ask for permission. The system may have to be dismantled when you move out, which can be time-consuming.

Good planning 

Once a wood stove is in place, it cannot be moved easily. The location of the wood furnace should therefore be carefully considered before setting it up and buying materials such as sand, gravel, clinker bricks and fireclay mortar. Such a stove is also a semi-open fireplace. It emits smoke and is always a conceivable fire hazard. Place it always at an appropriate distance from the house or other buildings - but of course still be easily accessible. A long exhaust pipe or flue pipe can otherwise prevent smoke from soiling the house façade. If there are children near the wood stove, this pipe should be insulated to prevent injuries. The flue pipe can become very hot. 

The basic framework for a self-built furnace is mainly made of bricks, but clay is also used. How much material you need depends on the size of the stove.  

Basically there are two ways to fire a wood stove: Directly in the baking chamber, where the food is also baked and cooked, or indirectly in a separate firing chamber.

Fixing irons into foundation

Once the site for the new wood stove has been chosen, the foundations must be laid. Because a brick stove can be really heavy, the foundation must be really solid.  It should be dug between 20 and 80 centimetres deep, depending on the nature of the soil. The rule is: the loamier, the deeper. The soil is then covered with a layer of gravel and cemented. If you put some iron in the foundation, you can be sure that the foundation will not break later, even in heavy frost. Bricklaying can only begin when the cement has dried and hardened properly, which can take around 14 days.

Building instructions for the wood stove

  • Building a base: it can either be brick on brick or poured concrete.
  • Building the combustion chamber: fireclay bricks are joined together with fireclay mortar, leaving a round gap of about ten centimetres for the flue.
  • Clinking the oven: plaster the fireclay combustion chamber with a thin layer of fireclay mortar so that the clinker bricks do not directly adjoin the fireclay bricks. Then brick up clinker bricks all around the baking chamber, with the smallest possible joints between the bricks. 
  • Wall up the flue: The area around the flue should be slanted, so the bricks are always moved a little further inwards. The flue should protrude clearly from the stove, otherwise it will draw poorly and it will take a long time for the fire to burn properly. You can also buy the complete element for the flue separately and build the rest yourself the way you want it.
  • Inserting the stove door: The stove door can simply be set up or connected firmly with clinkers around the stove by a frame. However, this construction method is highly susceptible to frost. Alternatively, there are sliding doors that stand on two small rails at the bottom and have a useful wooden handle.

Building with a kit

If you don't have enough manual skills or don't quite trust instructions from the internet, you can also use a prefabricated kit to build your brick stove. These are often made of refractory concrete or fireclay bricks and you still need a little skill, but there is no need for planning or sourcing materials. Baking on fireclay is particularly popular because fireclay is very porous, which means the stone absorbs moisture well and passes it on to the food being baked, resulting in a crispy crust and juicy interior. Prices for wood-burning oven kits start at around 1,500 euros for the very simplest and smallest version and often exceed 2,000 euros. For a large freestanding oven, the costs are even significantly higher. 

Outdoor kitchen with a roof

Whether self-built or prefabricated, an outdoor kitchen is of course really fun when the weather cooperates. If you can roof over your outdoor kitchen, you have a certain amount of protection from the weather, and the appliances can be permanently installed. In addition, a patio roof or pergola also prolongs the life of the equipment. Resistant materials such as teakwood, stainless steel or granite are generally recommended. Brick outdoor kitchens are particularly durable. However, it is not only rain, snow or frost that can damage outdoor kitchens; sunlight and UV rays also take their toll on the material. If, on the other hand, the open-air kitchen stands unprotected in the middle of the garden, the electronic equipment must either be well secured or movable, i.e. quickly stowed away in the shed, for example.

Looking for the perfect cooking experience with an open fire?

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A successful investment
Dear Sir or Madam After careful consideration, we decided to build an HK7 heating fireplace from Brunner and are happy with the decision. We would like to thank the stove building company Torsten Dix from 03205 Bronkow very much for the good advice and accurate execution on schedule. The fireplace is visually a modern jewel and ...
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Michael Schmidkonz: Dear Ladies and Gentlemen, We have bought a Brunner HKD 5.1 tiled stove. It is a top class product. Whether for ignition, continuing to heat or keeping embers burning - simply outstanding! With kind regards from Tirschenreuth Michael Schmidkonz
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Better some euros more for the brand quality of BRUNNER
Ralf Lenz: Dear Ladies and Gentlemen, The chimney sweep just came. He wouldn’t believe that we had left our stove burning all winter. It turns out that it's better to spend a few euros more on brand quality such as a Brunner stove than to buy cheap junk. It pays off in the long run - and the environment is happy too :-) Cordia...
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Jochen Gräve, Niederwerth: Good morning, Yesterday, between 4:00 and 5:30 p.m., your service technician Mr. Kieswimmer changed the brackets on my masonry heater door and checked and readjusted various settings on the EOS. I would like to express my sincere thanks to Ulrich Brunner GmbH and especially to Mr. Kieswimmer for thi...
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We heat the first winter with a stove installed by stove builder Stefan Hock from Bessenbach. Not only does the stove look great and fit perfectly into the picture, it also makes you really warm, and with far less wood than we needed before.
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After we got a new gas condensing boiler in 2017, Kachelofen Schulz from Rastatt-Rauental built a water-bearing heating fireplace for us at the same time. We are still totally enthusiastic about this combination, Mr. Schulz also showed us wonderfully how to fire optimally and burn wood effectively. Now we have obtained another B...
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Ladies and Gentlemen, I am currently planning the installation of my second Brunner tiled stove with the expert advice of the master stove builder Josef Müller, Runding. For expert advice on the installation of the Brunner B4 in the existing heating system, I sought professional help from Brunner: Friendly reception, sound profe...
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