GBE - German Black Egg - A mod of the famous LBE

[PizzaHead]

Hi everybody,

as I anounced some time ago in my Welcome Post, I'd like to show you my version resp. modification of a Little Black Egg.
But first of all, I would like to thank Villa Roma in particular for starting the invention and all other
people working on their own version. That was so much input and very worthful!

My gasburner is not von Bayou. My basis is a Wok burner from Manniu, China. I own this 25 kW rocket
since two years. And till now it was only used for its original purpose...

Here is the burner, the declaration is X72.

Image 1


As Weber kettles are relatively expensive in Germany, I decided to buy for my first experiments the cheapest
kettle from a local store. The diameter is 40 cm. (sorry for the "wrong" unit system! )

SONDRIO

Image 2


The hole in the middle fits to the flame diameter.

Image 3


The deflector stone has a diameter of 35 cm and hangs under the grilling grate.
On the grilling grate I placed the charcoal grate to have more distance to the pizza stone.

Image 4


I am an chemical engineer and engineers are lazy on the one hand side and on the other side (sometimes ) accurate.
So I decided to install also some thermosensors. This one is a PT100 with a cable insulated by silicafiber.


Here is the pizza stone with a diameter of 32 cm.

Image 5


I insulated the cables with some additional aluminium foil.


This is the upper part of the egg / kettle. Okay, what do we see here?
Obviously, this is the biggest alteration to the little black egg. My thought was, is it possible to bake
the pie without turning it? Therfore, I constructed an exhaust in the middle of the cap by using an
espresso can of Illy! In order to make sure that the gas will closely wind over the pie, I lowered the
ceiling of the cap. This is done by using the ash bowl. There is also a hole necessary...

As the hot air streams from all directions above the pizza to the center, I decided to alter the name
of the Little Black Egg mod to: German Black Egg or GBE! :D:D VR, I hope this is okay for you!

Image 6


On the left hand side you see the second thermosensor which measures the hot air over the pizza.
It is also a PT100. This ****ing part is also from china. I have been blowing three of them away by overheating
the cable insulation. In the meantime, I can say, that the upper sensor is not really necessary. It's sufficient
to measure the stone temperature.



The grasp was arranged diagonal. There is also an analog thermometer, but this one didnt show the needed
accuracy. So I'll dismount it soon.

Image 7


The space between the streaming edge and the pizza stone is ca. 25 mm.

Image 8

[PizzaHead]

Okay and now some results:

Heating with 0,5 bar and by far not full throttle takes 12 min to baking temperatures of > 350 °C.
Images were shot every 2 min.
Left sensor:  Stone
Right sensor: Air

Pies are coming now...

[PizzaHead]

Here are some pies. Most of them baked with 370 - 4xx °C stone and ca. 350 - 400 °C air. Enjoy!

[pizzaneer]

Very nice work, Matthias!  Pizzas look very tasty.  I'm curious about your topping combinations.

And kudos on taking a proven concept and exploring what effect an alteration will have.  Your unique redirection of the exhaust air into a torus shape looks like it provides even top and side browning all the way around, without the need to turn the pizza at all as it is cooking.  Is that the case?

Well done!

Brian

[PizzaHead]

Thanks Brian!

You've seen here three pies:
- Gorgonzala, pears, black pepper
- Mozarella, thin lemon slices, smoked graved salmon, rosemary (inspired by TXCraig, thx to him!)
- Salmon, mushrooms, mozarella

Yes, that was the idea, no need to turn the pizza during the baking process.
And to be honest, it works fine but sometimes - not! (see last pie; one side is more browned than the other) I dont really know why but I think about the following:
- Perhaps, the deflector stone has very well horizontally balanced?
- I have to make sure that the pizza is very symmetric and placed in the middle?
- Making sure that the stone is placed accurately in the center of grill grate.

So, in some cases, I'll have to spin the pizza once a bake.

Matthias

[pizzaneer]

What occurs to me as a mechanical process is that the kettle "fills up" with hot air from time to time, causing the airflow to concentrate on the path of least resistance.  That path can be determined by something as minor as a light breeze blowing across the exhaust pipe.  To mitigate this occasional circumstance, you could (1) try to force the division of the burner output before it reaches the flat bottom stone.  Try a cone or bowl shape centered under the stone stack. And (2) try a short flue and draft cap on the exhaust.

[lennyk]

Excellent stuff there,
where did you get the digital temp displays ?

You should put in the lazy susan platter like in the LBE thread.

L

[PizzaHead]

Good Idea, pizzaneer!
I'll trace first to force the burner output to all directions.

Havent seen that before in the LBE-thread. - Lazy Susan is pretty cool!
I'll think about it, how this cout fit to my current setup.

Actually, I also plan to build a bigger reactor. I recently bought the Weber Compact Kettle (18")! 

[chaspie]

Matthias, I'm just starting a build, and I'm considering emulating your top vent design.  Your pizzas appear to be cooking very evenly overall.  Have you sorted out the airflow issues with your top vent design or made any improvements?  How is the 18 inch "reactor" build going?

[PizzaHead]

chaspie, the airflow issue is not really an issue. I have to turn the pie once a bake, as one has to do with the LBE. Well my approach will be a heat resistant cone under the deflector stone. This one should split the air flow radially symmetrical. We will see...

Regarding the 18" reactor, I didnt make any progress except for unpacking and sorting parts. I will try it the same way with a centered exhaust.
I hope to start after Eastern...

What about your plannings?

[chaspie]

Good, I'm glad to hear that there isn't a problem with the centered exhaust airflow.  Having to turn the pie at least once per bake may just be inevitable for this type of cooker. 

I plan to go with your centered exhaust layout initially.  If it doesn't work out, I can easily convert it to a side vent.  I've ordered a 19 inch round 1/4 inch thick steel plate to use as a flame shield and platform for my stone.  It'll be centered in my 22.5 inch Weber so that hot air comes up evenly from all sides.  Hopefully the clearance around the disk will be enough for an adequate flow of air. 

I may not need a cone or other shaper in the path of the flame since I'll be using a 23 jet natural gas burner that produces a more spread out and slightly less intense flame than that produced by the high pressure propane burners that many people are using.

Good luck to you on your 18" build.

[sub]

Manniu Burner  my dream, but they're a rip-off from the german seller 

Nice pies !

I think the best for this kind of oven is dome walls in small refractory brick, fire the burner without the stone to get the walls to 800/900°  and then put the refractory stone to heat and bake.

[PizzaHead]

Manniu Burner  my dream, but they're a rip-off from the german seller 
...

I buyed my burners before a commercial import to the EU was established and I think, I was the first one who imported one burner to Germany.
So it is my fault....

The prices are not cheap, but the importer got the burners certified with the CE sign in the meantime. That cost a lot of money and the customer has to pay for it. And for spareparts you have a local distributor for contact.
Anyway, not my business, thankfully. You could also try to contact Manniu dirctly by email. But realize: Shipping costs are > 150 USD for a burner worth 25 USD + import taxes...