Wood vs. Gas
What is a Stone Hearth Oven?
Stone hearth ovens have been around for thousands of years and taken many forms. They have been made with any materials that were readily available (stone, clay, bricks, refractory tiles, etc.) and have gone by many different names (clay oven, brick oven, beehive oven, etc.)
Although materials and names have changed, there have been a series of easily recognizable features common to most stone hearth ovens, including:
- Shape – traditionally a dome or ‘beehive’ top.
- Heat Retention – a thick floor and dome made of heavy material that holds on to heat
- Open Cooking Flame – powered by an open flame, almost always inside the chamber
How is the type of fuel source important?
One of the most consistently asked questions in the world of modern stone hearth cooking is what role the fuel source plays in the performance of the oven and the quality of the food that it produces. The history of Wood Stone parallels the world’s growing understanding that, regardless of fuel source, it is the combination of stone hearth and open flame that provides the magic, not the fuel.
Since our founding in 1990, we have built over 13,000 ovens and shipped them to 75+ countries around the world. Today we build ovens powered by many fuel configurations – wood, gas, and several variations of gas and wood together. We even build ovens fueled by anthracite coal. Wood Stone was not always this way – our first 800 ovens were wood-fired only. Until 1994, we were firm advocates that “Wood made it good”. It was then, when two of our key customers came to us asking for gas-fired ovens, that we had a paradigm shifting experience. They explained that the costs and regulations of wood-fired equipment was making it impossible to open in some prime locations, and that training chefs to properly manage a wood fire could be challenging. A gas oven would allow them to open in locations previously untenable and standardize their operational training. Taking off our blinders and responding to customer requests led us to an innovation that has redefined not only our business, but the entire foodservice industry: the gas-fired stone hearth oven.
After over a year and more than a few attempts and restarts, Wood Stone invented a dual-temperature gas oven which utilized a radiant gas flame (RFG) and an underfloor infrared (IR) burner which in tandem most accurately duplicated the effects of a wood fire. We engineered a golden gas flame to reproduce the intense dry heat of a wood flame. The thermostatically controlled IR replicated the role of the coal bed in diffusing heat in to the hearth laterally below the top of the cooking surface.
Breaking Down Long Held Assumptions
Newly armed with an oven that could accurately reproduce a wood fire, we set to test cooking. We ran blind taste tests fully expecting the difference in taste to be immediately apparent. We were shocked with the results. Time after time the people taste testing could not tell if the food (pizza, bread, meat, seafood or vegetable) was cooked in a gas or wood oven. We brought in outside tasters, customers who had only worked with wood, and again their conclusions were the same. The food coming out of the gas oven was every bit the equal of that from the wood oven. Facing this unlikely result, we stepped back from our assumptions to gain perspective.
We thought the food coming out of the oven had always been excellent and we had always cooked with wood – our assumption was that the taste must be linked. However, our new gas ovens were telling a different story. We asked, “How exactly does wood flavor get into the food?” We realized that the only way to infuse food with wood flavor would be via direct contact – specifically with the smoke generated by the wood fire, similar to a smoker or wood grill. Although our wood-fired ovens generate plenty of smoke, they differed in one key way – the food was never in direct contact with the smoke. When food is on the hearth, the smoke rises above it and vents out of the oven. Does that mean that the great flavor is a figment of our imagination? Not at all – it simply led us to believe that the flavor is not the result of wood, but of the stone itself, and the intensity of open flame.
The brilliance of the open flame and the stored heat in the floor and dome create an intense cooking chamber which caramelizes natural sugars in the food. This unlocks waves of natural flavors simply inaccessible when using other types of ovens. The “fire-kissed” color evidenced by caramelized sugars is just as easily achieved in the gas oven as the wood. When cooking dough products directly on the hearth, another phenomenon also occurs. The direct contact generates a special type of ‘lift’ to the dough making it better than any sheeted or panned product and puts it in a different class than those baked by air in a conveyor.
Our extensive experience and personal history has taught us that the characteristics of “wood-fired” pizza remain present in both gas and wood-fired ovens, because they are actually the characteristics of stone hearth and open flame, not wood.
Important Considerations about Wood Ovens
- Wood supply and quality: In order to execute a wood-fired oven program, you must find a ready and reliable supply of quality wood. This can be quite the challenge, depending on what is locally available in your geographic region. Wood Stone ovens are designed to burn heavy hardwood. We recommend an internal moisture content of 15-20% – too wet and the fuel will not produce enough open flame for a balanced bake; too little and the wood will not form enough coals to thoroughly heat the oven floor. It is important to know that most wood purveyors are selling wood for heating homes, not cooking – paying close attention to ensure your fuel wood matches your specification is key.
- Wood storage and ash disposal: Another wood-fired consideration is the storage space required for wood. A cord of wood is 4’ x 4’ x 8’ – it needs to be covered to stay dry, but the majority should be outside of the building in order to avoid harboring pests. Cooking with a real wood fire also produces a fair amount of ash, which will need to be cleaned out of the oven and disposed of. This will require the proper tools – Wood Stone manufactures a heavy-duty, fully-welded particle shovel for removal, and a double compartment ash dolly to help avoid dumpster fires.
- Ventilation and Cleaning: Wood ovens, or any using solid fuel including coal, need to be vented independently of other pieces of cooking equipment. In a single story building, this can be a simple task, but in more complicated installations can become a significant expense. Additionally, the ductwork must be regularly cleaned to prevent flue fires – although the frequency of cleaning will vary (based on fuel quality and volume), once a month is a safe estimate.
- Operation: Operating a wood-fired oven is not brain surgery, but it does require the operator to be a fire-tender first and a chef second. The operator will need to place a new log on the fire every 15-20 minutes in order to maintain a consistent oven temperature. This task can be made more difficult if you do not have a predictable fuel source – changes in moisture or wood size can have a big effect on the efficiency of your fire.
Important Considerations about Gas Fired Ovens
- Supply and quality: Natural gas is incredibly consistent – once the supply is evaluated and connected it stays the same from day to day and is always available on demand.
- Ventilation: The gas-fired oven can be vented like any other gas piece of equipment – it can go under a shared hood or share its exhaust with another grease duct.
- Cleaning: The hood or duct over the gas oven is like that over any other cooking equipment and therefore can be scheduled at the same time.
- Operation: With a gas oven, operations are simplified and the chef can focus on cooking rather than fire tending. Rather than learning when to add wood, the operator can adjust the ovens flame with a simple knob similar to a range top.