The Hudson Oven is a seven and a half ton mobile wood fired bread oven. The oven sits on a dual axle trailer which is sixteen feet in length and approximately six and a half feet wide. All this rides on a rubber torsion suspension and is very smooth on roads and achieves speeds up to sixty miles per hour very comfortably. Remember that it’s not how much you can pull with a vehicle, it’s about how much you can STOP. This trailer also wields large drum brakes on each wheel which when coupled with my truck’s brakes stops the trailer on a dime even though the trailer is pushing the limit of my truck’s max tow capacity.
The exterior of the oven atop the trailer’s platform measures six feet long by five feet wide. The interior hearth and bake space measures five feet in depth by three and a half feet in width. The total width of the firebrick and its ceramic blanket insulation is what makes up the space between the inner and outer dimensions. The deciding factor for the thickness of the walls and hearth are up to the builder and baker to decide. More mass takes longer to heat, but more hot mass bakes more bread. For the purposes of a mobile oven, four inches (the width of one firebrick), is a capable potential heat battery for the walls and vaulted ceiling of the bake chamber. The barrel vaulted nature of the oven’s dome must be supported to keep from collapsing.
Much like the Flying Buttresses of the Notre-Dame, a steel Beam harness is fabricated in place around the walls of the oven before the dome is constructed. A barrel vaulted brick dome is not self supporting like a round oven style as you may have seen with pizza ovens. This brick pattern creates immense outward pressure due to the arched nature of its construction. Check out these photos from a large stationary oven built by Jonathan Santiago
of Hearth and Timber @hearthandtimbr based in Florence Massachusetts. Jon is a true master of his craft. He designs and builds masonry heaters, true Brick Ovens as well as mobile ovens, and timber frame structures. If you are in the Northeast and are interested in acquiring an oven like the one Hudson Oven operates, I suggest you reach out to Jon. There is no single design solution for an oven of this style and Jon will work through the details with you to ensure you are happy with the final build. Lead times and price may vary but I suggest you approach a mobile oven build project with a budget greater than twenty thousand dollars and timeline greater than four months.
The oven I operate was designed by William Davenport of Northern Vermont and it was built by a team of masons back in the mid to early two thousands. Mr. Davenport was a mason who developed a system for producing these mobile wood fired ovens and produced around fifteen of them. Among the team of masons was Jeremiah Church of Boreal Heat @boreal_heat out in Ashland Oregon. He is still a practicing master mason who designs and builds masonry heaters, mobile wood fired ovens and even builds structures with plaster and straw bale construction. Last and not least, is a gentleman named Antoine Guerlain who was part of the team that built the fifteen or so mobile wood ovens. Antoine built his own double deck wood fired oven and ran a bakery out of it in a greenhouse near Hudson, NY for many years before handing it off to an esteemed employee and moving North. All three of these individuals have been very formative and forthcoming with their knowledge and expertise in my journey to understand the potential of the mobile oven that I operate out of currently. Unfortunately the original builder of our oven (William) is no longer a practicing mason and I have never had the opportunity to speak with him.
The Masonry Heater Association (MHA) is a member based three hundred dollar per year, national club with masons from all around the country as members. I am also a member but more of a fly on the wall and am glad to be such. This community of masons is small but mighty in that they are likely responsible for thousands if not tens of thousands of masonry heater and oven builds around the US. They are a welcoming group which hosts an annual oven building workshop in the Carolinas where attendees (anybody who purchases a ticket) hand builds a variety of different style ovens over the course of a week in the hills of Little Switzerland, North Carolina.
The functionality of these ovens are designed for Bread Baking. Think of a wood fired oven as being the top of the pyramid as far as capability when it comes to design and oven style. These ovens require thick masonry walls which absorb heat over the course of many hours. While firing an oven it is perfect to make pizzas just like you would in any thinner walled pizza ovens you might have encountered. These ovens require many inches of high efficiency and high temperature insulation for the purposes of retaining and radiating heat into the bake chamber once the coals and ashes are cleaned out. A wood fired bread oven will stay at cooking temperature for up to five days after a thorough soaking of heat without the addition of more heat. Our oven has produced slow cooked meals which I can honestly say are among the best meals I have ever had and done it in an irreplicable way.
Working with a wood fired oven is not for everyone. It requires endless attention to detail, cleanliness, vigilance, tolerance of heat, and its own set of specialty tools. You will get to know firewood more intimately than you ever thought possible. The species of wood you collect for firing, the quality of the wood, it's hydration and its size are all factors to a successful firing. You also need good firewood in quantity and a way to store it properly. I enjoy every element of it. From the constant tinkering, collecting of tools, learning one species of tree from another and tending a flame with the ultimate goal of producing something as unique as the process.
You will need a good hatchet, and splitting-ax. These two are the ones that I have used for seven years and they are getting better with age. A coal rake, hearth brush, ash pan and bucket are also required for clean outs. As a full time baker I leveled up when I learned about ash vacuums. I acquired one and my cleanout time has reduced to ten percent of what it was and the result is superior. When starting out I took pride in starting “One Match Fires” but have since graduated to a blow torch and Map Pro Gas for simplicity's sake. If you can’t start a fire with this set-up, then something is horribly wrong!
Even more exciting then reading about ovens is the prospect of building one yourself! I have built two ovens out of Hudson River Clay. The first of two resides on the farm property behind the Greenhouse of Stone Barns Center For Food and Agriculture in Pocantico Hills.
The first step is to build your pedestal. At least ten inches larger in width and depth than your desired baking hearth size. The second step is to create an insulation layer that will separate the mass of your oven structure from the pedestal. You don’t want your heat to leak into the pedestal, you want it to bake bread! The oven at Stone Barns was a rebuild of an existing oven. The stone base was assembled and there was an insulation layer made out of empty wine bottles encased in a cob material. This insulation puck was the base upon which I spread sand and laid modern firebrick (the only purchased material for this project.) Once the firebrick was in place I prepared my Brick by mixing 2 parts sand and one part Hudson River Clay. I utilized a brick mold lent to me by a friend named Ron Breland (Alternative Beekeeper, Philosopher and Gardener). Once the bricks were molded and sun-dried, I stacked them into a dome atop the firebrick atop the insulation puck atop the pedestal. Once the dome was complete I added one more layer of the 2:1 sand/clay mixture for additional mass for storing heat. I then layered on as much cob as I could process. This final layer of sand, clay and straw is important to keep the clay brick dome from losing heat into the atmosphere.
Our second clay oven resides at the historic site of Philipsburg Manor in Sleepy Hollow, NY.
We were commissioned to build a functioning oven that was of the style of a bake oven from the Colonial Era. This design was very similar to what I had built before but I was able to start from scratch. First, my friend Ron and I created a very large pedestal out of fieldstone upon which we used modern insulation material (Perlite and Insulating Firebrick). Perlite was poured over the base first to fill any inconsistencies in the surface and provide an even platform to lay the Insulation Brick. The Bricks are firm and lightweight with a High R value and High Heat rating. Next was a very thin layer of sand atop the insulation brick for further leveling and then I laid out a Hearth utilizing the same Firebrick as the first oven.
This time I turned the brick on edge to achieve four inches of thickness and set them in a herringbone pattern.
Once the hearth was complete I
prepared and utilized one hundred and twenty hand made bricks I made over three weeks in preparation for this build. Shoutout to Nik Bucci and the Bucci family for the use of their historic Brick making property which is rich in local clay deposits for the materials for these brick.
Once I laid the brick dome atop the firebrick hearth, I then reinforced the oven entrance with a basic steel frame bent from stock metal and layered on additional 2:1 sand to clay material for additional heat retention.
The next steps were to wrap the dome in insulation of which I utilized a modern Ceramic Fiber Blanket first, then normal rock-wool insulation and finally a layer of cob. This oven is built in the same way a colonial era oven would have been but its functional materials are modern and lend themselves to a vastly superior baking experience. This oven can be visited when walking the property at Philipsburg Manor for one of their tours.
An excellent resource for building clay ovens is Kiko Denzer @kikodenzer @earth.oven who spells out the many elements of building an earthen oven in his book “Build Your Own Earth Oven”. An additional resource is Alan Scott of “The Bread Builders, Hearth Loaves and Masonry Ovens”. Regardless of your level of interest in Ovens and Bread Baking I appreciate you taking the time to read what I have to share on the subject. Furthermore I would appreciate any further questions you might have regarding these topics. Consider it logs on the fire for me to keep sharing what I know. Thanks again!
Sincerely, Chase Harnett of The Hudson Oven