Noah is a working baker, builder, and farmer who has built and used earthen ovens, a classic Alan Scott oven, and now a very fancy Spanish Llopis oven. Here he provides very clear and detailed data on the differences in fuel consumption and food production between earth and (massive) brick. In short, he explains exactly why an Alan Scott oven may not be the best option for a home- or small-scale baker.
Elbers owns and runs The Orchard Hill Bakery in New Hampshire. He participates in the brickoven group on yahoogroups, which is where this comment came from, but as you can see from his website, he’s clearly spending more time baking and building than computing….HOORAY! For a lovely story about him and his bakery (by a lovely French lady), go here. For fascinating documentation of the installation of his Llopis oven, go here.
His comparison is below. Copied w/his permission…
— Kiko Denzer
Re: Thermal Mass
Posted by: “noah elbers” breadwks AT sover.net
Thu Jun 26, 2008 4:40 pm (PDT)
When I was just starting out commercially I baked in a minimally insulated, 4-5″ thick cob/clay oven. Here was my schedule and quantities just to give you an idea. This was a 5 foot deep oven, 3 ‘ wide app. but scaling up or down does not affect the number of loads much at all.
I would fire the oven from cold at 4:30 am. With three stokings (a brisk fire most of the time) the oven was fully saturated by 10:30 am.
2 loads of pizza (6 each load)
3 loads of bread (30-36 loaves each load)
2 loads of cookies or bars (totaling 150 pieces) sometimes pies, but not always, up to 15 on a regular basis, but over 100 at thanksgiving and christmas.
25 lbs of granola
By the end of the next day the oven had cooled enough to dry fruit like apples and plums, or herbs and tomatoes from the garden. Three days after sweep out the oven would be back to air temp.
Light up was very easy in this oven even from cool temps since it heated so fast, wood quantity was miniscule compared to my later AS design, and baking quality when I was within it’s production capacity was better I feel.
When I built the AS oven, a 4X6, I routinely baked upwards of 700 lbs of dough on a single firing, (500 loaves) and a few times over 1000 lbs of food (bread plus wedding catering). Those things when properly heated can really hold on to some heat, but until they are nice and soaked with heat (something I didn’t fully appreciate until after two years of baking in it) I don’t think they bake very well.
When I retired my AS it took well over a month for it to come back to room temp. Amazing, but not useful for home bakers. The other downside of the AS design for home use I think is that once the thing is fully heated, you either need to wait a long time before it enters the lower temp zones better for more delicate things, or you need to have huge amounts of food to bake. The low mass oven will drop lazily but steadily once it is up to full heat, and in a matter of hours you can go from great pizza to great lemon meringue pie. Half an hour at pizza temp, 2 hours in the bread zone, 5 hours for cookies and desserts, 12 hours for braising and roasting, 24 hours for drying etc.
I have no agenda here, just ten years of small scale commercial baking experience that spans three ovens now. I was basically a home baker when I started, the business grew and required greater baking capacity, and I now no longer bake in a black oven. I think retained heat baking is fascinating, rewarding, and generally as good as any other cooking method. My motive in going on and on about this is to help people who have not baked with retained heat understand some of the heat dynamics of different thermal materials. Saving on costs, fuel, air pollution are tangential for me. The experience of using the oven is what I care about most, and I share this from my experience with the two types of ovens. (now three, but the Llopis is a whole different animal)
Orchard Hill Breadworks
breadwks AT sover.net
East Alstead NH 03602
(603) 835 7845
Jim Buckley says
I found Noah Elbers’ experience with cob and AS ovens very interesting and instructive.
I built a 36″ Superior Clay oven in our office. See http://www.buckleyclan.net/Monroe/oven.html
It’s taken me a little practice but I have found that it’s really important to get the oven “saturated” – hot enough – as Noah says. This oven, which is only 36″ in diameter inside with walls about 4″ thick plus another 4″ of fiberglass and insulating concrete, takes about three hours to get “saturated” to about 1,200 degrees – or whatever temperature burns the inside clean and my 1000 degree thermometer is pegged. Since it is lighter (and smaller) than Noah’s cob oven it heats up faster but also cools down faster so that after four or five hours it’s only about 400 degrees.
More comments and construction details at http://www.buckleyclan.net/Monroe/oven.htm