Author Topic: Maximus Wood Fired Oven  (Read 7716 times)

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Offline Chicago_Fire

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Re: Maximus Wood Fired Oven
« Reply #20 on: June 19, 2013, 08:58:23 PM »
Well here's a good try. Emergency neapolitan dough and a 4 minute cook. Solid base. Sorta chewy. Not that yeasty.  We're pretty happy for a second try. Decent oven.
« Last Edit: June 20, 2013, 10:03:18 AM by Chicago_Fire »


Offline synaesthesia

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Re: Maximus Wood Fired Oven
« Reply #21 on: June 20, 2013, 08:03:09 AM »
Nice going...Hope to see /hear more of your adventures with this contraption.

Offline synaesthesia

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Re: Maximus Wood Fired Oven
« Reply #22 on: June 20, 2013, 09:34:15 AM »
Who said anything about a guarantee? Mass plays a major role in heat balance. Insulation can serve much the same function. I'll guarantee you can't have balanced heat without sufficient mass or insulation, AOTBE. The more you rely on the fire to maintain temperature, the less balanced the oven will be. Convection is not the relevant heat transfer mechanism to consider here - it's radiant heat that is the meaningful variable.

Oh don't make things up. Thermal mass only comes into it if you have a prolonged fire and there has been enough absorption of heat through time for it to re-radiate over time. Not in the the 20 minutes it takes for these oven s to heat the base and have a top heat which moves via convection, and is aided by reflective heat more than it would be with radiant heat. Radiant heat is irrelevant largely with the 304 steel, it is better with mild steel. There are lots of conventional ovens with thermal mass that do not have a desired heat balance, and that desired heat balance is achieved by managing a number of variables. Take a closed room in a stone castle with a large fireplace and the same size room with a small fireplace, you do not get heat balance just because the walls are made of stone and have thermal mass capacity. The same principles apply to an oven, albeit in a smaller and more concentrated situation.

Offline Tscarborough

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Re: Maximus Wood Fired Oven
« Reply #23 on: June 21, 2013, 01:56:39 PM »
I think I would shoot for Neo-NY in that oven ,it should excel at that style.

Offline TXCraig1

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Re: Maximus Wood Fired Oven
« Reply #24 on: June 22, 2013, 01:57:53 AM »
Oh don't make things up. Thermal mass only comes into it if you have a prolonged fire and there has been enough absorption of heat through time for it to re-radiate over time. Not in the the 20 minutes it takes for these oven s to heat the base and have a top heat which moves via convection, and is aided by reflective heat more than it would be with radiant heat. Radiant heat is irrelevant largely with the 304 steel, it is better with mild steel. There are lots of conventional ovens with thermal mass that do not have a desired heat balance, and that desired heat balance is achieved by managing a number of variables. Take a closed room in a stone castle with a large fireplace and the same size room with a small fireplace, you do not get heat balance just because the walls are made of stone and have thermal mass capacity. The same principles apply to an oven, albeit in a smaller and more concentrated situation.

And what exactly did I make up?

If you want to bake at 300C, Iím sure the oven will suit you just fine and (lack of) mass wonít be an issue, but letís be honest, thatís just a glorified conventional oven and not what Iím talking about. Lack of balance is a minor inconvenience with a huge margin of error at low temps like that. Iím talking about pushing up into the 450C+ range where the margin of error is meaningful. The importance of heat balance is not linear with temperature. The IR from the fire needed to hit high temps in that oven will dominate the heat balance or lack thereof.
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Offline Chicago_Fire

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Re: Maximus Wood Fired Oven
« Reply #25 on: June 22, 2013, 11:05:32 AM »
I don't think I'd call it a glorified oven.  An oven your referring to doesn't burn wood.  The only difference between this oven and a masonry oven is the thermal mass of the ceiling.  Lets face it the only purpose of the upper thermal mass is to top brown the pizza, so yes you do need a flame and a bit longer to do that in this oven.  But the down heat is heat whether it's in a form of convection or radiant it provides the same top browning action, albeit it takes 4 minutes instead of 90 seconds but that only comes into play with Neapolitan styles.   The benefit of cooking with flame is that you do get smoke and char which adds a delicious edge to the pizza unlike thermal mass.  While I don't get commission selling these ovens I would say if your living in an urban setting and come home from work at 6 and want wood fired charred pizzas at 7 this is an excellent choice.

Offline TXCraig1

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Re: Maximus Wood Fired Oven
« Reply #26 on: June 22, 2013, 11:56:42 AM »
My original comment was not intended to be a critique of your oven - rather a correction of a misstatement by synaesthesia. For fast warm ups and 300C/5minute pies, I have no doubt it is a great oven.

Quote
Thermal mass aids heat retention and re- radiation, you can hit high temps by the strength of a sustained fire alone. It will be less able to retain heat as long as a masonry oven  but you do not need that condition unless you are catering regularly on a commercial basis.


While it's obviously correct that mass retains and re-radiates heat, it's an incorrect assertion that the primary function of the mass is to retain heat because you need it for commercial volume.  This isn't a pizza stone we're talking about.

You got it partially correct when you wrote "the only purpose of the upper thermal mass is to top brown the pizza" But, it's more than that however. Its something you may not really appreciate until you try to push your oven up into the mid 400's+ (C). As you noted, the hotter you go, the larger the fire you will need because you're bleeding so much heat without suitable low thermal conductivity mass or insulation. As the fire gets larger, it becomes more and more difficult to balance the heat on the parts of the pie not directly in the path of the IR coming from the fire. Convective heat is not the same as radiant. Radiant heat increases with surface temp^4. As the mass of the dome and walls increases in temp, radiant heat increases exponentially. Convective heat transfer increases linearly with temperature. The hotter you get, the more pronounced an imbalance becomes.
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Offline grillsnovens

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Re: Maximus Wood Fired Oven
« Reply #27 on: December 15, 2013, 10:33:46 AM »
Hi Guys!

I feel obligated to explain the scheme of the Maximus oven which was previously posted in this thread, and its relationship to heat.

Please see below schematics of Maximus and a typical EPA wood heat stove. As many of you may know EPA was introduced to provide more efficient technology into wood burning - cleaner, more efficient, hotter. A crucial component of an EPA stove - the piece that larger makes all of these advances possible if the Baffle. The purpose of the baffle is to make the smoke path longer. A little known fact is that wood smoke can be burnt, just like any other fuel, and it will provide heat. However, it can only be burnt at very high temperatures. If smoke goes right into the chimney from the fire chamber it doesn't have enough time to heat to the smoke burning temperature and hence hot unburnt gases escape into the air. This means: air pollution and heat loss / inefficient heating. The way to make wood smoke burnt is to keep it inside the oven for longer time + provide it with some fresh combustion oxygen / air. This is where the baffle comes into place - it stands in the way of the smoke and sends it twice along the entire depth of the oven before the smoke is allowed to escape. The smoke heats up and gets reburnt inside the oven. A good EPA smoke will emit little less than vapor out of it's chimney - relatively cold and almost completely devoid of unburnt gases.

This is how the Maximus oven was built. It's the only oven i'm aware of which employs the EPA system to provide hotter and more efficient heat. As the hot smoke travels under the baffle from the back of the oven into the front it encounters fresh air from the door opening of the oven and get reburnt. The result is that you have fire even inside the chimney of the oven - over the baffle! And hence cleaner air, hotter inside, less wood to use. Hope this clarifies the oven's construction.

Offline TXCraig1

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Re: Maximus Wood Fired Oven
« Reply #28 on: December 15, 2013, 02:20:49 PM »
Hi Guys!

I feel obligated to explain the scheme of the Maximus oven which was previously posted in this thread, and its relationship to heat.

Please see below schematics of Maximus and a typical EPA wood heat stove. As many of you may know EPA was introduced to provide more efficient technology into wood burning - cleaner, more efficient, hotter. A crucial component of an EPA stove - the piece that larger makes all of these advances possible if the Baffle. The purpose of the baffle is to make the smoke path longer. A little known fact is that wood smoke can be burnt, just like any other fuel, and it will provide heat. However, it can only be burnt at very high temperatures. If smoke goes right into the chimney from the fire chamber it doesn't have enough time to heat to the smoke burning temperature and hence hot unburnt gases escape into the air. This means: air pollution and heat loss / inefficient heating. The way to make wood smoke burnt is to keep it inside the oven for longer time + provide it with some fresh combustion oxygen / air. This is where the baffle comes into place - it stands in the way of the smoke and sends it twice along the entire depth of the oven before the smoke is allowed to escape. The smoke heats up and gets reburnt inside the oven. A good EPA smoke will emit little less than vapor out of it's chimney - relatively cold and almost completely devoid of unburnt gases.

This is how the Maximus oven was built. It's the only oven i'm aware of which employs the EPA system to provide hotter and more efficient heat. As the hot smoke travels under the baffle from the back of the oven into the front it encounters fresh air from the door opening of the oven and get reburnt. The result is that you have fire even inside the chimney of the oven - over the baffle! And hence cleaner air, hotter inside, less wood to use. Hope this clarifies the oven's construction.

I'm not sure that the oven works the way you think it does. In a non-catalytic wood stove, combustion air is drawn in from under the stove. The combustion air is preheated as it is channeled around the oven. Hot primary combustion air is fed directly into the fire, and hot secondary combustion air is released through holes in stainless tubes above the fire, just below the baffle. You can see this in the diagram you posted above.

It looks like the combustion air in the Maximus design enters through the oven mouth. Some of this cold air is going to mix with the gasses coming off the fire, and I would think, lower the temperature preventing secondary combustion, baffle or no baffle. This may be why the exhaust seems "relatively cold." The exhaust airflow path is similar to a non-catalytic, but it appears that is where the similarities end.

FWIW, EPA stands for US Environmental Protection Agency. "EPA stove" refers to stoves that are certified by the EPA to meet the requirements of the Clean Air Act. It's not a stove design per se.
Pizza is not bread.

Offline Chicago_Fire

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Re: Maximus Wood Fired Oven
« Reply #29 on: December 15, 2013, 03:27:56 PM »
I purchased the Maximus and posted these pics. I bought the wood burning oven for the convenience of quick starts and quick cool downs. It does that fine. My concerns now after using it for about 10 times is that the top cooks much faster than the bottom of the pizza. I've been using Sharkeys New York style emergency dough. The flavor and usability of the dough is fine for me. I'm not a pizza fanatic.  Besides rolling the dough thinner does anyone have any suggestions for a more balanced result? Thanks.


Offline TXCraig1

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Re: Maximus Wood Fired Oven
« Reply #30 on: December 15, 2013, 05:22:07 PM »
I purchased the Maximus and posted these pics. I bought the wood burning oven for the convenience of quick starts and quick cool downs. It does that fine. My concerns now after using it for about 10 times is that the top cooks much faster than the bottom of the pizza. I've been using Sharkeys New York style emergency dough. The flavor and usability of the dough is fine for me. I'm not a pizza fanatic.  Besides rolling the dough thinner does anyone have any suggestions for a more balanced result? Thanks.

That's the problem with a quick start-up. Getting the oven interior hot is one thing, getting the floor hot is another thing entirely. You are probably not getting the floor thoroughly heated. Even if it is hot enough on the surface after a quick start-up, it's not hot right below the surface, and much of the heat is going to be moving down away from the pie rather tan up into it.

I'd guess it will take at least an hour at full operating temp and maybe a good bit longer (how thick are the floor tiles?) for the floor to be ready to bake. 
Pizza is not bread.

Offline Chicago_Fire

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Re: Maximus Wood Fired Oven
« Reply #31 on: December 15, 2013, 05:46:58 PM »
Yes I agree the times when I fired it longer and left the fire longer on the cooking zone the better the base was but then it cooked way quick so I guess finding the balance is going to be key. The masonry base is over an inch thick as far as I can tell. Can't see further down. 

Offline TXCraig1

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Re: Maximus Wood Fired Oven
« Reply #32 on: December 15, 2013, 05:48:39 PM »
Yes I agree the times when I fired it longer and left the fire longer on the cooking zone the better the base was but then it cooked way quick so I guess finding the balance is going to be key. The masonry base is over an inch thick as far as I can tell. Can't see further down.

If it's an inch, I would think it will take every bit of an hour to heat up enough.
Pizza is not bread.

Offline grillsnovens

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Re: Maximus Wood Fired Oven
« Reply #33 on: December 16, 2013, 08:08:18 PM »
This phenomenon is in fact sometimes present simply because it's easier and quicker to heat up air than to heat up clay (a much more dense material). Here is a trick that works very well, i have done it myself many times:

build a fire in the deep right or left corner of the oven. then when you are ready to put your pizza inside move the fire to the other corner of the oven and place your pizza in the place where the fire just was! you will see the bottom of your pizza cooking much faster, sometimes too fast )) you can repeat this every 2-3 pizzas moving the fire from corner to corner. There is even a special tool for that i saw in Europe - to be honest i used to use a hand saw for that purpose )) but you will see the difference - i guarantee!

Offline sirp2000

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Re: Maximus Wood Fired Oven
« Reply #34 on: May 30, 2014, 05:02:43 PM »
Hi there.

I've just bought one of these but am having difficulty in getting the wood fire to get going.

I tried for over an hour tonight but only got it to smoulder.

Can you please give me advice on how to get it going?

Thanks
Phil

Offline sirp2000

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Re: Maximus Wood Fired Oven
« Reply #35 on: May 30, 2014, 05:04:44 PM »
Hi there.

I've just bought one of these but am having difficulty in getting the wood fire to get going.

I tried for over an hour tonight but only got it to smoulder.

Can you please give me advice on how to get it going?

Thanks
Phil

Offline TXCraig1

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Pizza is not bread.

Offline JConk007

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Re: Maximus Wood Fired Oven
« Reply #37 on: May 31, 2014, 10:23:12 PM »
and worth every penny Harbor freighthas em for $29!saves me a solid 1/2+ startup time with the mobile
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Offline narmnaleg

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Re: Maximus Wood Fired Oven
« Reply #38 on: September 02, 2014, 04:37:48 AM »
@Chicago_Fire any update on how the maximus is performing for you? Mine is being delivered tomorrow and I'd appreciate it if you could share any advice.

Offline narmnaleg

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Re: Maximus Wood Fired Oven
« Reply #39 on: September 05, 2014, 06:19:56 PM »
This is Max, I cured him last Wednesday. Since last Wednesday the sense of urgency to make pizza has been growing. With Saturday pizza not being possible due to other commitments, I thought Friday night after work WFO pizzas would be my best option.

When looking at my attempts below, please keep in mind that not only is Max a new experience for me, but I've never cooked in a WFO before and I'm a complete newbie at making pizza. I know I made mistakes all the way through the process, but the best part of this hobby is that you get to eat your mistakes ;) so here goes, all feedback and suggestions are welcome BTW. I have so much to learn  :-D

Started preparing the dough on Friday morning at almost 6am with the view of a Friday dinner pizza meal. The result were 7 pizza blobs. Started cooking at around 6.30pm and the results are below.