Category Archives: Wood-fired oven

Bakery/Shed 3: Hello walls

Construction projects are notorious for going over budget and off schedule. Somehow this winter, it seems the stars have aligned over our project; apart from rest and rain days, there has been no down time. Credit for working that magic goes to our contractor Craig Swingle.

In the last half of February, Craig and Ben framed the walls, and Ben laid the drainpipe and moved a bunch of gravel around. He helped finish waterproofing the foundation, then he and I filled the area behind the retaining wall with rocks and gravel.

Then the sheathing went up. It looks like the oven is outside the building, but it will be tied in with a concrete floor, shed roof and wing walls.

At some point, we took a break to start farming again. We put the plastic on the greenhouse and started seeding for the 2016 season.

The last steps in this phase were placing the beam over the little “hallway” to the oven, and building some stairs up to the bakery.

The building has to sit high off the ground because of how we built the oven. Last year, if you recall, we were scrambling to get the oven built, and didn’t think through how it would tie in to the rest of the building. In building it on the high part of the pasture, we essentially fixed the finished floor height for the rest of the building.  Early next week, we’ll show you the roof.

Bakery/shed 2: Foundation and Floor

It was bound to happen. Any winter construction project has to build in time for snow. Ours arrived mid-January, and delayed the foundation by two weeks.

But once things thawed, the project entered a phase where things start taking shape very fast. It is very exciting. We were delighted to hire our neighbor Scott Franklin to build the foundation. This is what he and his crew accomplished in three three short days.  They did a wonderful job.

They incorporated charred block from our first oven into this foundation, which feels good and has a nice resonance.

The next step was to frame the floor, and we both helped Craig, our awesome contractor, finish this stage in three days. On the first day, we built the beam and secured the rim board.

On the second day, we added the joists, and on the third, we glued on and screwed on the subfloor. This floor is not going anywhere!

And now that we have a floor, our first thought is: let’s have a square-dance on it!  And if we have our way, that is just what will happen at our annual old-time music party, Thorny-O, which is coming up this weekend.

Bakery/shed 1: There’s a hole in the ground

We kicked off the new year with a little ground-breaking here at Little Hat Creek Farm! After months of planning our new bakery and packing shed, the yellow machines showed up to dig. We could not have anticipated how exciting it would be to see the realization of our dream!

Last week JD Pippin carved out the site. There were rocks–from the 1969 Hurricane Camille landslide–but not nearly as many as we had feared. JD came back with a backhoe, dug the footer, and then the concrete truck showed up. Early next week, the foundation should appear, laid by one of our neighbors here in the Hollow.

Stay tuned for more updates!

Let’s fire ‘er up!

In the two-odd months since we last checked in with an oven update, we have been learning how to use our beautiful new oven.  It is most definitely a learning-by-doing kind of process; there is no manual for this sort of thing.  I had some previous experience with other so-called “black” ovens in Toronto and a clay oven we built last year, but this one is bigger, and way, way more massive.

At its basic level, a black oven couldn’t be simpler to operate.  There is a single chamber that holds both the fire and whatever you wish to bake.  You build a fire first and heat up the masonry walls, floor and ceiling of your chamber, like charging a battery. Then you remove the coals and put in your bread; it is the heat stored in the masonry “battery” that bakes the bread not the fire itself. In other words: fire heats masonry, masonry bakes bread.

In practice, building a hot fire is challenging.  It takes a lot of labor to cut and haul firewood, so the more heat you can coax out of a given amount of wood, the better.  The first thing our oven taught us was that we needed to use top quality firewood; seasoned, split, and stacked oak or locust stored in a shed.  As it happens we had a handy abandoned goat shed not too far from the oven.

Apart from wood, the other ingredient fire needs is oxygen, and this is a function of air supply, or draft, how air moves through and around the physical structure of the fire, and the outlet, or flue. I find it helpful to imagine the air flowing through the oven like water in a brook–you want a well-contained and directed swift and smooth flow with no dams, stagnant pools or disruptive cross-flows.  All parts of the fire should have access to air, so I try to think about the bottom and back and sides of the fire–all the parts that I can’t see.

This oven draws its air supply through the ash drop, which is a gap in the masonry in the front of the oven that opens into a cavity below the oven where ash is stored.  There is an access door on the side of the oven that I crack to allow fresh air to be drawn in by the fire.  I have discovered that removing the door completely is counter-productive, especially on windy days, when the wind blows up into the oven and scrambles the flow of air. The flue (chimney) is opened with a simple handle.  It has two positions–open and closed, so there’s not much nuance there.

Where I have the most control is how I build the fire itself.  In the morning, I load the oven with a single layer of wood, trying to loosely cover the whole hearth.  I close up the oven to let this wood heat up for an hour or two, and so that any residual moisture from the night steams off.  I then put two brush bundles on top of the wood and stuff some paper underneath them.  One match lights both pieces of paper, which lights the brush bundles, which lights the wood.  In a minute or two, there is a hot fire burning across the front of the oven.

I close the blast doors, which protect the fire from wind while still allowing smoke to escape up the chimney, and which will eventually keep most of the heat of the fire out of the bakery, and wait.  It is so tempting to mess with the fire, but (a) you’re doing more work, and (b) the doors are open and you’re poking at it so your fire isn’t establishing a smooth draft. In an hour or two, I come back and find that the fire has burned itself part-way back into the oven, and it is burning cooler–you can tell by the smoke. I want it to burn hot and clean, and to continue moving back, so I push the fire back to the middle of the oven to consolidate the heat.  I move the fire back one more time to get it in the back of the oven.  I still don’t put any more wood on because I know that there is fresh wood behind the fire.  At this point, after the fire has been burning for 3-4 hours, I see the temperature of the firebrick start to budge.

Temperature is measured in the middle of the oven by six thermocouples embedded at three depths in the firebrick hearth and in the vault, or ceiling.  When there is fire in the oven, the thermocouples closest to the surface are hottest, while the deeper ones–the ones that tell me that the battery is heating up–take longer to clue in to the fact that there is a blazing hot fire in the oven.  This property of being slow to take on heat (and therefore release it) is one of the things people mean when they talk about thermal mass.  We built a massive oven because we wanted it to release heat slowly, so that I could eventually bake all day, but the cost of that is that it heats up just as slowly.

Back to the fire, which we left burning away in the back of the oven.  By the time the base layers of masonry start heating up, I start adding more wood. Rather than shoving the wood back to the fire, I put it up front and walk away.  In a few minutes, I know it will start burning, bringing the fire back up to the front of the oven again. In an hour, I move those coals back and add more wood to the front. Because moving fire around is hot work, I try to get the fire to move itself around the hearth. When I first started firing this oven, I kept the fire in the back of the oven for most of the firing, but in this new oven that resulted in over-baked bread in the back and under-baked in the front; the oven’s way of reminding me that it has a front-to-back dimension that also needs attention if I want even heat, which I definitely do.

This back-to-front-to-back dance is repeated until the base layers surpass 450 deg F, usually 1-2 more rounds. At this point, I spread the coals and remaining wood over the front 2/3 of the hearth to distribute the remaining heat. I have found that by the time it has burned down to ash, the deepest bricks will be between 550 and 600 deg F.  Before I go to bed, I close up the oven, putting in insulated “plug” doors that block the flue and ash drop, so that the oven heat can equilibrate.  As I sleep, the heat flows through the masonry into cool areas so that by the next morning, if I did a good job, all thermocouples register around 575 deg F–the ideal temperature to start baking bread.

Meet our new bread oven!

When Ben and I got back from our vacation in January and discovered that the clay oven that we built last year was unusable, we had a moment of “Oh %$&#, what do we do now!?” We had pretty much already decided to build a new oven this year, but we were hoping to use last year’s oven in the meantime. That obviously was not going to happen.

I counted the weeks remaining before markets start–thirteen–and, like a grad student trying to meet a thesis deadline thought, “that’s not enough time!” and then tried to make it happen anyway.

Jan 4-Jan 28 (3.5 weeks) The first step was figuring out who was going to build our oven. We had built our first one, which lasted a year, but we were ready to hire a professional to build our second one. After many phone calls and emails with bakers and builders (thank you all!), we chose Eric Moshier and his crew at Solid Rock Masonry in Minnesota. We had visited one of Eric’s ovens at Muddy Fork Bakery in Bloomington, Indiana in December, and liked what we saw.

Eric Schedler, the baker at Muddy Fork, had nothing but glowing reviews of his new high mass well-insulated single-chamber oven, and we listened. Solid Rock got the job too, because they were available to come down in early March, and they could do the build in just one week. Plus the price was right.

Jan 29-Feb 13 (2.5 weeks) Then came the design email marathon. For what is essentially a box that holds a fire, there were lots of things to think about. How big should the hearth be? How much bread will we want to make in ten years? Will we be using sheet pans? What kind of door do we want? How do we keep steam in? Eric held up his side of the bargain, responding patiently and promptly.

Feb 14-15 Decompression break for Thorny-O, our annual old-time music and dance gathering! Some thirty friends came over for a house square dance, good food, and a tiny instrument jam featuring Sophia on miniature fiddle!

 

Feb 16-Feb 22 (1 week) We hired the good folks at Lithic Construction in Charlottesville to excavate, pour the footing, and build the foundation. We were very lucky that Jarrod and crew were willing to take this job on such short notice. And then it snowed, which shut down everything in Charlottesville. The week delay was actually fine with us, because we also grow vegetables, remember? We used that week to put the plastic back on the greenhouse and start our little seedlings.

Feb 23-Mar 1 (1 week)  Jarrod and his crew from Lithic were awesome. They braved the snow and soggy ground to build us a solid foundation, finishing on time despite the weather delays and wet conditions. They dug a hole, laid a reinforced concrete slab, built up a hollow concrete block foundation and the poured another slab that supports the weight of the oven core. And then Jarrod did us a huge favor by loaning us their scaffolding for the remainder of the job so that we wouldn’t have to rent it.

Mar 2 Arrival! Eric, Mark and Jacob arrived! The three Minnesota Masons pulled up in a truck that was pulling a trailer full of everything they would need for the week. I know from my past life running field research projects that it is no small feat to organize all the things you know you will need, the things that you might need, and the things to improvise the things you didn’t know that you would need.

This is Eric Moshier–he led the project and designed the oven. He is gentle, avuncular, and focused. He raises most of the food for his family on his 10 acres, including a giant tom turkey named Fred, whose smoked breast we had for dinner. His breakfast was hotcakes, eggs, and a cup of strong coffee blended with a dollop of grass-fed butter.

Jake is the youngest, biggest, newest guy on the team. He humbly called himself “the grunt,” slinging seventy pounds of firebrick with one hand. He also welded my complicated set of oven doors, and he fixed the tie rod of our tractor with a piece of wire. His breakfast was a couple bowls of puffed cereal and a Monster energy drink.

Mark is a scrappy life-long mason who had the dubious priviledge of crawling in the oven to clean mortar off of the hearth. He also sells fish bait and antiques, could name the manufacturors of our cast iron cookware at a glance, and would receive a letter if you just addressed it to “Trapper.” His breakfast was a cigarette and a cup of drip coffee.

All three of them lived in our house for the week. They brought a lot of food with them, and we made it our business to cook it. We made what we thought was an astonishing amount of food, but somehow there were never leftovers. The first night the five of us put away a pork pot roast that Jake brought, a venison roast that Eric brought, three pounds of Ben’s sage-y mashed taters, and a berry pie. The second night we had soup made with smoked breast of Fred and wild rice that Eric’s friend harvested, mustard-encrusted chicken legs that Mark brought, chicken livers in sour cream on toast, and a salad. You get the idea.

 

Mar 2-9 (1 week) This is the week the oven got built. One bonus to hiring masons from Minnesota to work on your winter project in VA? A little snow is nothing! Not when you build yourself a cozy shelter around your project, complete with propane heat, lights, an ipod, and energy drinks. One bonus to building an oven on a farm? You have a tractor to move heavy stuff around. OK, so Ford had some trouble with the mud and snow, but it did a good job.

So in nine weeks we went from the “Oh $@%#” moment to an oven. We still have to paint the OSB and make the site ready for baking, but we’ve been slowly curing the oven, steadily increasing the size of the fires to heat up all that mass. At this rate, the oven is on track to bake bread for our first markets.  Phew, we made it!

The pictures that follow are the highlights of the construction, and they more or less speak for themselves. All told, the guys at Solid Rock were disciplined workers and a pleasure to be around. We would reccommend them highly to anyone.