Generally the determination of building an igloo dome or barrel vault pizza oven should be identified by aesthetics, cost and the types of food which are to be cooked. Although barrel dome ovens are usually larger, allow for greater room for bread, and may offer a slightly uneven cooking area, they are still be equally viable for cooking pizza. The choice will ultimately come down to personal opinion.
As can be seen by the below table, the cooking area of the hearth is dramatic and perhaps surprising depending on the dimensions of the oven. For example a igloo dome oven with a diameter of 42inches (106cm) has a similar cooking floor space as a rectangular barrel dome oven with dimensions of 35" x 39" (90cm x 100cm). Floor space for a rectangle is simply depth multiplied by width. eg. 90cm by 100cm = 9,000cm2. Floor space for an igloo or circle is radius squared multiplied by 3.14. eg. For a 76cm igloo this equates to 382 = 1,444 multiplied by 3.14 = 4,534cm2.
Rectangle Area = Width x Depth
Circle Area = Radius2 x 3.14
They might be both efficient baking ovens but each is built for a particular purpose based on a higher level of efficiency in baking. Igloo dome pizza ovens are found to be more efficient in baking pizza. The physical structure speaks much of itself when it comes to pizza baking. Being designed in circular form it resembles a similar shape to pizza. It simply means that once the pizza is put inside the oven the entire dough is cooked evenly as the heat inside the dome is evenly distributed and reflected. Through this process the pizza is properly baked. Barrel vault oven are recommended for breads or pasties baking as they are rectangle shaped and in varied sizes unlike traditional pizzas which are circular in form. Professional bakers prefer a rectangular floor design as it improves the ease of utilise all of the floor space. Where a professional baker may be able to bake 60 loaves of bread on a single firing, a igloo pizza oven would only manage 35 loaves. Despite the mentioned considerations, both oven shapes may be utilised to bake break and cook pizza. The shape may play some part in cooking however this is generally not of a degree that it should influence the type of oven chosen.
By the structure alone one can directly tell which is easier to clean over the other. Obviously the barrel vault pizza oven has the advantage over igloo dome type because deposited coals inside the chamber can be easily clean up away from the sides. Likewise placing firewood for firing up the oven may become more trivial. Once the baker has become accustomed to either form the issue of cleaning and firing up ceases to be an issue to reckon with.
Both rectangle and igloo circular ovens take the same amount of time to heat up, cool down and radiate heat. Fire placement is not important as long as the oven has reached a point of even heat distribution beyond the heat up phase. While the oven is reaching the desired temperature the heat generated by the fire may be greater than the radiant heat being output by the oven walls. During this period food placed in the oven may experience a higher impact of temperature from one side rather than even heat from all sides. This results that pizza may need to be rotated such that it will not burn on one side while the other side remains uncooked. Once the oven has reached the desired temperature and the door has been closed for a period of 5 minutes, the oven will establish an even heat distribution such that all walls and floor space radiate the same heat towards any inserted food. This established distribution will generally be the same for both oven shapes.
Some individuals suggest that barrel vault ovens take 2 to 3 times longer to heat than the igloo dome. This will likely only be the case if the barrel oven walls are substantially thicker than the igloo oven. If the thermal mass and insulation of the ovens are similar, the time taken to heat should generally get the same. The thermal mass of these ovens are usually the dome and hearth bricks and mortar combined. Additionally because of the claim that the barrel ovens take longer to heat up they are also accused of requiring more fuel (fire wood) and having difficulty in reaching and maintaining the high heats required for cooking pizza. Again these measurements will be dependent upon the thermal mass, insulation, and the opening more so than the shape of the oven.
No. Although the heat distribution will not be 100% perfect this is not an issue that will influence whether bread or pizza may be cooked in the oven. The difference in heat distribution will be so limited that it will be difficult to identify any impact.
A number of oven owners consider constructing an igloo dome pizza oven to be more laborious and costlier than building a barrel vault pizza oven. Due to the roundness the structure of an igloo dome is indeed harder to construct over a barrel vault type. As constructing an igloo dome may be more difficult to build then it may follow that more time and budget are needed. Rectangular floor space designs are largely utilised by industry, potters and bakers due to the ease of build, longevity of the construction and the ease of filling the rectangular floor space. Improperly or badly designed igloo ovens are unlikely to last a long time, whereas rectangular ovens are simple to design and will last a very long time. Simple cob or mud ovens are commonly built in a circular igloo design as a prototype or as a hobby for only intermittent use. This type of oven can be built inexpensively without the use of a flue, chimney or door.
As fire bricks are rectangular in shape the construction of rectangular structures such as a barrel vault ovens is necessarily easier. When building circular structures the construction may become more difficult. In particular laying the hearth in a circular shape would result in many large gaps which would prevent the easy application of food such as pizza. Outside of cutting the bricks to lay flush while remaining in a circular pattern, it is recommended that the hearth be laid as a rectangular floor that protrudes beyond the bottom of the circular dome placed on top.
The Neapolitan igloo dome is traditionally built for the well established Neapolitan pizza. These ovens generally have a lower vault ceiling but maintain the same oven diameter. The resulting ceiling is flatter and closer to the hearth thus providing the maximum amount of radiated heat onto the pizza. The oven opening will likely be slightly smaller to allow for the lower vault height. This smaller door may limit the size of the dishes which can be placed within the oven comfortably. The building of these ovens can be more difficult than similar Tuscan style domes. Because the ceiling is much more flat the potential for the bricks to fall is pronounced. With careful construction and utilisation of stable supports while the cap brick is placed and the mortar allowed to cure the possibility of issues will be reduced.
Tuscan igloo domes again maintain similar diameters to the Neapolitan igloo however have a rounded brick wall thus providing a higher vault ceiling and a taller oven entrance. These ovens allow for the cooking of much larger dishes and pans which can pass easily through the opening. Although the ceiling is not as close nor radiates as much heat to a pizza placed within the oven, Tuscan style domes are adequately capable of cooking perfect pizza.
The standard barrel vault oven is in the shape of half a barrel with one end completely enclosed, and the other end largely covered with a small door as an entrance. The door height is generally based off of the ratio of 60 : 100 per the door and vault height respectively. For example a vault height of 18" (46 cm) correlates to a door height of 11" (28 cm).
Another form of barrel vault has one end entirely enclosed and the other end entirely open. This type of oven gives the user more cooking options than just bread or pizza as the opening is wide enough to allow grill inserts for wood-fired barbequing and smoking of meats (when sealed with a door). High temperatures can be reached quickly as the open design allows for full oxygen air-flow which feeds the fire that generates the heat. Once the desired temperature is attained, closing the oven with a metal or insulated door keeps most of the heat inside.
Since this type of oven has a door on the outside of the oven, minor heat loss can occur through the flue located inside of the oven. To prevent this loss and retain even more heat, a heat-retaining damper can be installed in the flue or a chimney cap with a built-in damper can be installed on the top of the chimney. With the proper use of a door and damper, almost all of the heat generated inside of the oven can be retained for long periods of time.
Once the oven and insulation has been created whether igloo or barrel vault, a protective shelter or enclosure is generally built to protect from rain and improve the aesthetics of the oven. In some instances builders opt for a style that encloses the entire oven in a structure that resembles a small building with a roof. Within this design the oven will operate as normal however will be protected from the elements by the outer walls.