white oven vs black oven

[fsucpa]

Still planning my build, been lurking and reading here for a while. Have a couple of questions. The Finnish company Tulikivi produces a wide range of modular heaters and cook stoves, using this super effecient masonry finnish heater idea. I guess from reading that it must have a lot of mass to heat up, that slowly releases over time in the house, and also seems to get so hot that it has some kind of secondary combustion that leaves no soot to exit the chimney. Pyromasse, in Canada uses this idea to make a white oven, but I can't wrap my brain around how that can be used for my pizza oven.

I have read alot of posts here on this site, and am pretty sure I don't want to build a A.S. oven, but have seen no discussions on white ovens or any along the lines of the finnish masonry heaters. Can someone shed some light on how these things fit into the grand scheme of ovens and oven design, functionality and ease of use.

Thanks


Tom

[dmun]

Re: white oven vs black oven

We keep hearing about masonry heaters, and white ovens, and russian ovens, and so forth, but nobody here has reported on building one, and how it works. Other than the big bakery ovens that Alf works on, this is terra incognita here at FB.

So share the results of your research. We'd like to hear about it.

[Unofornaio]

Re: white oven vs black oven

In the simplest explanation I can give the white oven concept is really geared strictly toward a baking oven.

In order to get proper pizza you need to have a fire going in the baking chamber. Can you make pizza in a white oven? Defiantly but I believe its a different product than one that comes out of a fired bake chamber.

In the next few months I will begin construction on my white oven concept model a scaled down version that I will eventually build here at the bakery. I have been working on the design of on and off for several years now. The primary function of the oven is for breads and baked goods. I have tried to contact Alf to run some design questions by him but have never received a response ..It sure would make it a little easier, this thing is very complex.

Yes please share your info on the white ovens you have come across.

[james]

Re: white oven vs black oven

I think the White ovens are very interesting and am looking forward to seeing Uno's progress.

Tom, how are you thinking of using your oven? Why type of food, cooking, frequency of firing, etc. are you going to be doing? Are you mixing in home heating?

I have a mental picture of how a white oven works in a bakery setting. You are heating the masonry, and you can burn just about anything (even pellets I think) in the fire box. You just want a nice stream of heat and flame blowing up into the cooking area. The temperature moderates in the cooking dome, and you cook as much bread as you can before the oven cools down. My guess is that fuel costs almost as much as flour in that type of bakery. Heating efficiency and bakes per firing are critical.

I'm not so sure how a white oven would work for home cooking. Easily regulating the heat from the fire inside the oven is one of the main characteristics of a black oven -- and it's something that works really well for weekend (and evening) cooking. You can fire the oven quickly and keep the oven "in tune" for the type of cooking you are doing, all pretty easily.

Is a white oven as flexible?

I will look forward to learning more. That, and how heat and cooking come together. Sort like the British Aga stove.

James

[fsucpa]

Re: white oven vs black oven

I am not sure what I am going to build yet, just doing my due dilegence research first as I will be living with whatever I build for a long long time. I kind of get the feeling that the white oven does not get hot enough for pizza, only breads and such, although there is hardly any info out there to find. I do know that my build will include a fireplace and a pizza oven, as the pizza oven won't give me any real heat for all my friends to gather around. The one thing I don't like on all the outdoor kitchens I have seen so far, even if they have a pizza oven and a fireplace is that darn gas grill. I left propane 4 years ago and haven't missed it and won't go back. Wood or charcoal for my direct/indirect grilling.

It would be nice to combine the fireplace and the pizza oven in one vertical unit, using a common chimney. Like fireplace below where the wood storage is for most other units. Any ideas?

Tom

[james]

Re: white oven vs black oven

That's a tricky one. The chimney on the fireplace is in the back and the pizza oven is in the front. Also, the fireplace is shallow and the pizza oven is deep. The problem is that the chimney for the fireplace wants to run right where you set the pizza oven.

It can be done, by running the chimney for the fireplace to the back or side, but you are limited to a very small pizza oven because of the space used by the fireplace.

Lot's to think about -- and always lots of design trade-offs. Let us know how it goes.

I also gave up on propane 5-6 years ago. I've never looked back. :-)
James

[dmun]

Re: white oven vs black oven

There is a long tradition of fireplaces next to ovens, stretching in this country back to the seventeenth century. Some of the earliest ones had the bake chamber behind or to the right of the firebox, the idea being that there would only need to be one flue. It soon became clear that having the oven that close to the open fire made it hard and dangerous to use. Here's a picture:



of the kitchen in Mount Vernon in Virginia, from the early 18th century. Notice the oven to the right of the fireplace, it's a round brick oven like a small pompeii, by the way. You can also see the diagonal flue above the oven, leading to a two flue chimney. My point is that an oven in an open fireplace was a mistake in the 18c, and it is now. If you are using both, you are going to burn your feet cooking in the oven. You may want to consider placing your structure on a diagonal, with the oven opening on the "kitchen" side and the fireplace on the adjacent sitting area, with the two facing ninety degrees apart. Bringing two flues together to form a two flue chimney is not a simple task. Combining the two in a single flue will create draft problems, and won't be allowed under code if it's a part of your house.

The ovens of masonry heaters are over door-enclosed fireboxes, and many of them still face away from the fire, toward the kitchen area.

[Dutchoven]

Re: white oven vs black oven

Okay guys! I have a bit of experience not with building these but having seen photos of and CAD drawings of designs. As Uno will I am sure relate to they are a very challenging process from initial conception to final build. A true "white oven" the exhaust gases from the burning fire NEVER enter the oven chamber itself. They get redirected through a system around the bake chamber heating the firebricks from the opposite side. The system can work very well for bread because as the temperature curve drops you can refire without having to clean the chamber once again. Many French bread ovens are called "guellard" ovens and vent the exhaust gases from a separate firebox into the oven chamber through the use of a removable, usually cast iron, elbow called the "guellard." This also allows the possibility of refiring in between bakes as the temperature curve begins to fall. So this in truth would be a hybrid between the "white" and "black" ovens. The flue systems of both of those are tricky. For the "white oven" you have to slow the gases down enough to allow them to heat the masonry but, and it is a big one, not slow them down too much to create the possibility for condensation and creosote issues/fire hazard. The "guellard" has to have the system to move the gases into the oven chamber and then also one to remove them from the oven chamber plus some sort of "diverter" to close off the oven from outside air coming in and going out and yet another flue to exit that external firebox's exhaust. The masonry heaters you spoke of use the same process as the "white oven"of slowing down the gases through a system of either horizontal or vertical flue tubes(which is why some designs include a "white oven") but they have the same challenge. That is the reason why most firecodes for stove pipe require very specific relationships between the length of horizontal runs and vertical runs...and also the restriction of angles to connect them. Uno would know more about this being in the trade I think.
I hope this shed some light on this topic. I can probably find a way to dig up some more information on this topic but, I will attach a CAD design I have and maybe you can see some of what I spoke of. The other is a design for a German bakeoven.
Best Dutch

[Unofornaio]

Re: white oven vs black oven

Very nice. I have some drawings of a Russian oven I will try to post them.

This is EXACTLY why I am going to build a 1/4 scale of it first maybe even smaller, the routing of the gasses is the most difficult design challenge. I can build the darn thing its just making sure its gonna work Its been a frustrating l-o-n-g process of gathering the minimal amount of info that is out there. These guys (understandably) are tighter with this info than my grandmother was with her cookie recipes.

Alf--if you read this I beg of you to contact me so I may run my design by you. I promise I will not go on a wild oven building spree and share all the secretes. Don't forget I'm 100% Italian and we are know for our ability to keep secrets I'll pay you..

Please excuse my desperate plea guys...Hey just in case he reads it

[fsucpa]

Re: white oven vs black oven

Hey Dutch,

Great detailed reply. Can you tell us if the white oven or the french version ever even get hot enough for the proper pizza baking temps? Also, since I love the idea of the the fireplace, and also love wood/charcoal cooking, does anyone want to chime in on cooking over wood. The splitjack system seems designed for fireplace cooking and seems alot like a churrassco.

I know that William Rubel Hearth Cooking and Fireplaces, talks alot about fireplace cooking and his feelings about the shortcomings of the rumsford fireplace design in regards to cooking vs heating an area/room. Maybe I should just go for a rumsford for heat and some kind of semi shallow firebrick pit for wood/charcoal cooking with grates for the wood to burn on and a adjustable grate for the food above, no chimney system for this, just live with the smoke. I really liked the pics someone posted about the italian restaurant that had an exceptionally deep fireplace at waist high, firewood in the very back, drops thru the grate, to be pulled forward by the cook for use under a raised grill. All the fumes out thru the oversized chimney. Wow ! The options are mind bogleling. Be assured that I respect and value all of your suggestions everyone.

Tom

[Unofornaio]

Re: white oven vs black oven

Can you tell us if the white oven or the french version ever even get hot enough for the proper pizza baking temps?
> the guellard ovens super heat the chamber, when fired it literally looks like a flame thrower shooting the flame across the hearth. This "collar" can be rotated from right to left at different times during the fire so flames hit different areas of the chamber.

I suppose if you really want to get technical the white ovens can be brought to a temp to do decent pizzas. the result would be similar to a gas deck oven with stones that many pizza shops still use and produce good pizza. However the fuel and process necessary to do so and maintain that temp is prohibitive for home use compared to traditional Pompeii style oven. You are looking at several hours of heat up as apposed to an hour or so, by that time it becomes a chore instead of fun. These oven work in a commercial environment because the temp is always several hundred degrees and firing is merely bringing it back up to baking temp.
In my opinion the ovens were not designed with retained at the top of the list as other designs of that era were, but the masonry still holds much heat from the previous bakes.

Again tec speaking you could make the oven thin walled enough to heat up faster.

[Dutchoven]

Re: white oven vs black oven

Uno gives a very good answer and I will add one additional aspect. The retained heat masonry oven with a fire inside heats in 3 ways, conductive, convective and radiant. The white oven will heat with conductive and convective but it lacks on the radiant heat because there is no active flame in the oven chamber. One could probably make some excellent pizzas in the very early high heat stage as many suspect the early retained heat bakers used to do to use up some of the heat before they began baking bread.
Best
Dutch

[Unofornaio]

Re: white oven vs black oven

Dutch-

In no way did I mean to answer on your behalf I was here an thought I would answer, looking at it now I realize it was addressed to you, sorry.

%$#@ loud mouth Italians

[Dutchoven]

Re: white oven vs black oven

Uno
No sensitivity here! I am just happy we have so many points of view and areas of expertise. All of us have so much to contribute we should all speak up when so inclined. I would also love to hear of your ideas with regard to your "guellard" oven. Something I have been interested in for some time but, I don't think I have the ability to construct one. I have nearly finished the repointing of a building that may become our woodfired bakery or pizzeria. Building around 100 years old. Once exterior pointing is done then I have to go upstairs and deal with 3 old coal fireplaces that used to heat the living quarters up there...should be fun...there are no flue tiles and it seriouisly deteriorated the both the internal and external masonry. It was a solid brick wall...brick footings...3 ply wall for the first floor and then 2 ply upstairs...almost no cement in the mixture...almost entirely lime and sand.
Quite a challenge!
Best
Dutch

[Unofornaio]

Re: white oven vs black oven

No sensitivity here!
>I'm glad thanks.

I would also love to hear of your ideas with regard to your "guellard" oven. Something I have been interested in for some time but, I don't think I have the ability to construct one.
>I didn't mean to imply I was building the guellard design, nope not for me. This oven I have designed is a true white oven, flames will never enter the baking chamber. I had my fill of years of building a fire and raking that da@# stuff out only to have to do it again the next morning. My oven was 8x10 so it was a freaking wheel burro of ash every day and the mess and the...I hated it. Nope this one will be much better to control, I can fire it as I need heat, cool it with the vents and I will never have to time my dough for the oven to be just right. For all intensive purposes it will function like a gas deck oven (ok well sort of) but the control is something I need. Using the black oven for breads just added too many variables to the baking process that I cared to deal with. At first they were a challenge and part of the romance of it all then it became a pain in my...well you get the idea.
I have nearly finished the repointing of a building that may become our woodfired bakery or pizzeria. Building around 100 years old. Once exterior pointing is done then I have to go upstairs and deal with 3 old coal fireplaces that used to heat the living quarters up there...should be fun...there are no flue tiles and it seriouisly deteriorated the both the internal and external masonry. It was a solid brick wall...brick footings...3 ply wall for the first floor and then 2 ply upstairs...almost no cement in the mixture...almost entirely lime and sand.
Quite a challenge!
> sounds fun...NOT. It has always been a dream of mine to be "The Italian guy that lives above his bakery" sound like a very nice building. Are you getting any help from your local county or city programs? There are a lot of revitalization programs out there these days, it may help pay some of the bills. Some of these programs are a totally good thing they improve the business district and revive old buildings. Others have so much red tape forget about it.
I did a few re-pointing jobs with my father years and years ago it was the most boring thing I have ever done. But now days the machinery they have is freaking awesome you can do a whole house in a day..not much market for that out here though. I sure do miss all the brick buildings though. Is funny how you grow up around things your parents do and see and then eventually fall in love with the same things..Atleast I think thats where I got my love for masonry. I sometimes wonder was it my family that instilled this love for building and architecture in me or was I just born that way. I could drive around all day and just look at old buildings.

When I was little my father and brother took the coal furnaces out of my grandmothers house and apartments those things had more steel in them than most cars and trucks do today.. what a mess it was I do remember all the cool slag formations though..kinda scary that for decades and decades people heated there homes with this toxic gas..surrounded by asbestos It sure is a different world now.