Norfolk build

[chas]

Thanks for the encouragement re the fracture Dave, I'll carry on with my firings on good days and monitor it - I'd got as far as figuring that if I vermicrete the outside and re-render with K-rend, there will be a sort of slipping plane that may allow minor damage in the brick dome without it showing in the outer shell. Not that I'm too bothered about 'cracks of honour' but really don't want water getting to my clay... I'm not sure if it ever achieves the strength and water resistance of a brick - it's never going to get baked at brickmaking temperature, is it?
It's all relative though, isn't it:



Found that while googling wfo lamb. As before, click on the pic to view fuller size.

Anyway, the prospect of slapping on Devil's Porridge seems takes on a more acceptable shine in view of your lamb suggestion.

I found an Aussie video ref to slow-baked lamb www.sbs.com.au/food/recipes/slow-cooked-oven-baked-lamb-kleftiko and reckon that I can easily get the 350C needed - just need to find out if I can get the four hours cooking time with the door shut - I do have a door. Yesterday, the afterthought spuds came out 4 hours after the focaccia went in and the temp was 100 at that time. It was after dark and cold, so lack of insulation was almost certainly a factor. 

I'll put a cap on the chimney to help retain heat further. That would have the same effect as pushing a door past the flue to seal the heat in...

Chas 

[cobblerdave]

G'day Chaz
With the temps your oven will not maintain that 350 C it will fall but makes no difference to the results. If you check out that recipe you'll find the domestic oven reciepe calls for 150C and 5 hrs. Trust me though in the WFO oven the results are different , much better
Curing your oven and cracks. What you doing is basically drying the water from the oven. The thing about clay is that its up to 20 per cent water and once dry can loss up to 15 per cent of its size . One cause of cracks.
Other thing that happens it that the water is expanded into steam. That's 1 ltre of water becoming 1500 ltres of steam and that's a lot of force. On other cause of cracking
The third thing that happens is that as heat goes up the top of the dome heats faster and of course drys faster than the lower parts of the oven. As it is dryer it heats up faster that the parts down lower. Uneven expansion and of course more cracks.
That's why I say take it easy with the temps and allow the oven to rest between fires so the moisture migrates to the dryer parts of the oven.
There's another thing that comes into play with clay ovens and I'm not sure how this effects your oven with its clay mortar and brick structure. Basically the clay oven losses the moisture that is locked chemically within the clay. This happens between 350 C and 500 C temps that are possible in a WFO. What is does to the clay is dehydrate it and it cannot then be remixed with water to become mold able clay again. Now this doesn't happen to the complete clay mass but only to the inside surface of the clay oven. The largest part of the still is able to take up water like clay does. This of course is not vitrification that only can happen at temps of over 1000C.
The fact that a clay oven can still take up water and of course steam it of means that most cob ovens use a permeable lime bases mortar rather than a Portland based one which doesn't breath and may trap the moisture. You guessed it more cracks
In was very interested in building a cob oven when I started out but with the rain events we can get here I decided against it and built in brick wth hombrew mortar.
Insulating with pearlcrete . The stuff takes ltres of water to mix it in and will put you right bak in the drying stakes . Best dryed by heaps of sun wind over weeks and weeks before firing and finally sealing.
Might end up not being able to be dried in your current conditions.
Sorry for the doom and gloom but except a few cracks and just take it easy with the fires and you'll be right
Regards dave

[chas]

Cheers, Dave - much useful observation there, and 'top crack' / 'damp migration' perfectly explained... probably better to hold off insulating for the time being then, and get to know the beast better.

Work and weather preventing any firelighting this week, but I'll be giving the lamb casserole a go this weekend regardless of anything: if the thing isn't cooked after 5 hours down from a steady 350Deg I can finish it indoors, so nothing wasted and much performance info gained!

Chas

[cobblerdave]

G'day
This recipe works well enough in a domestic oven but in a WFO it really sings.
Like all recipes it really needs the meat to be given a quick " brown " first to bring up those lovely meat colours and flavours that's if you doing at 150 in the domestic oven.
But in the WFO you seal it all up first no browning off required. The high start temps do this for you even sealed away and those lovely flavours are not lost to the air . Wait to you finally break the seal ofter that wait.
Just for interest search the "maillard" effect, it describe the browning of proteins which is different to caramelization.
The other thing that goes on and this is my own experience is that the heat radiated from the brick surface and wood flame is different as that of a microwave or gas or electric cooking. No great scientific explanation , I'm just sure its different.
I can cook bread in the gas oven on a pizza stone and its pretty good! In the WFO it takes on a different character and it's very good even my poor bakers skills can't muck it up.
Regards dave

[chas]

Despite the cold drizzle, this weekend I was determined (and had promised the family) to have a go at Dave's kleftiko while tempering the dome with another prolonged burn... a week should have seen dampness migrating, surely.

Anyhow, here is a shoulder of lamb, chunked, and installed with some spuds and garlic, rosemary and oregano etc in an old WD baking tin.



The oven got to 300Deg in about 2 hours of carefully managed burn - nothing too big to begin with - and then I let the flames die down and bunged it in.

The result was, as promised, after a slightly longer 4 and a half hours, a succulent, fall-off-the-bone dish of comforting loveliness. Not a lot of browning to the meat, but I put that down to the low start and rapidly falling temperature - and it in no way spoilt the result: it was beautifully cooked.

I am a total convert to the merits of insulation when cooking on built-up heat... my original rapid cook pizza-and-flames style is ok, but for the relatively small outlay in time and money, the extra layers over the dome have to be done to extend the use to slow baking - if that's what you aspire to. All those here who told me so - you were right. I'll probably wait now until a dry spell (February?) to get going with the vermicrete, and carry on with burns and cooking experiments as time/weather/family interest remains in order to progress the dome drying.

NB anyone following the wet clay approach might a) build at a time when the weather is reliably dry b) arrange some roof over the build at least until the waterproofing render and c) resist rendering it with K-Rend or anything else until the clay is dry and baked hard. My way looks nice and finished, but is a handicap to drying.

Chas 

[cobblerdave]

G'day Chaz
Glad you liked the lamb. Its a pretty cool recipe . On the subject of " browning " the meat wouldn't have gone brown in the traditional sense, but those flavours you usually associate with browning are there. My own experience I found the taters had soaked up the flavours from the meat.
On the subject of insulation. Yes of course you can make a pizza oven that's I insulated and again you can make I slower cooking oven that is uninsulated . But with insulation both work better. In both the insulation traps the heat that you put into that brick... the mass of the oven. Pizza ovens work continuously with a small flame to keep the temps lost to the cooking. You don't have to stop to reheat the surfaces. With a slower cook the temps slowly go down and the heat is used inside the oven and doesn't get lost to the outer surfaces .
Regards dave

[chas]

Yep, insulation seems the way to go...

This weekend's burn, in cold drizzle again but I'm still keen, had to take place with the poly cover clear of the chimney but over the dome, and focaccia as a by-product. Well received by everyone later that evening.

Chas

[bookemdanno]

Hello Chas!

I've been away for some time with other commitments and its good to see another East Anglian build. A good one too!
Well done on the build and getting some nice cooking done too. That cracking seems to be par for the course really as there's some pretty intense heat from the chimney meeting the cooler exterior render. Had the same "problem" but haven't really come up with a solution. Currently just leaving it and considering it "character".


Whereabouts are you? I'm on the Norfolk Suffolk Border at Bungay.

[chas]

Hi, and thanks for the compliments and reassurance. The crack's not got worse (tempting fate?) and as you'll have seen, once the weather dries early in the New Year, I'll put a shell of vermicrete and K-Rend over it which will hopefully keep it out of sight. For the moment I light small fires in there, with or without cooking, at least once a week. Latest venture was to finish off a Hairy Biker pulled pork recipe which called for a smokey kettle barbeque... hang on I thought, I've now got something better than that!

I'm up near Acle, among the good ol' boys and tattooed wimmin.

Chas

[kstronach]

once you get the oven insulated and re k rended i don't think you'll have as bigger problem with the cracking. at the moment that krend will be exposed to high heats which won't be helping. its a bad point where the render meets the flue if you have a look at my linked post you can see like a bulkhead around the chimney where i domed up some extra vermicrete because that was the only place that was getting hot and since i did that and got my waterproof coat on i've had no problems. if you wanted to make certain you could leave a 1/4 inch expansion joint anywhere where the renders going to meet your brick chimney then fill it in after with some high temp silicone sealant.

ukwoodfiredovenforum.proboards.com/post/15507/thread

all the best

keith

[chas]

Thanks, Keith - just waiting for our traditional dry February to get that ol Devil's Porridge on the go... the K-rend expansion joint will be part of it now too.

Chas

[chas]

Memo to self: must get one of these 'Tuscan Grills' as per Cobblerdave ukwoodfiredovenforum.proboards.com/thread/2072/idea-far.

One of my abiding 'eating memories' (and there's been a few) is of a little roadside place in Normandy where, on ordering the lamb chops, the lady got a sort of Tuscan Grill (then I just thought it was a natty indoor bbq rack)  put it over the log fire and grilled my chops. Total fluke as I didn't know that's what she'd do, and total show-stopper in the dining room - seemed like everyone wished they'd thought of that...they were delicious.

Wood Fired Oven: the gift that keeps on giving.

Chas

[cobblerdave]

G'day Chas
the Tuscan grill is not mine, but rather an oven tool available from forno bravo. 14"x14"x4" cast iron

It may not be my idea but I'm smart enought to recognize a good idea when I see one.
A grill plate from a old bbq and some 6" bolts and you've got youself a great cooking instrument.
Build a fire in the oven and burn it to coals. No worries about pizza temp, it's a bed of coals your after.
The warmth of the oven and the ability of the walls to throw the heat back makes this a great way to Bbq. The meat or what ever is heated from the top like a hooded Bbq but without the hood to block what's going on.

 



This little burnt offering to the WFO gods is a boned out marinated chicken. I claimed to have some smarts before but if you look closely the grill bars are running across not toward you like a BBQ grill should. Trust me it makes it hard to flip the chicken over, that's why the battered appearance, tasted alright but apearance wise!






Good thing of not having the hearth to the blistering pizza temps is that a flatbread of more than flour salt water and yeast is possible. The same floor then cooked up some nan bread containing gee and yoghurt they were nice and soft and sweet. If I'd done the same at pizza temps it would be instantly black.
Im sure you can produce the same type of grill easily. There a lot of fun and the food cooked over coals is to die for.

Regards dave

[chas]

Feb 13, 2015 11:54:29 GMT cobblerdave said:

G'day Chas
the Tuscan grill is not mine, but rather an oven tool available from forno bravo. 14"x14"x4" cast iron

Dave, so sorry not to have acknowledged this back in February - can't see how I missed it and it's a brilliant follow-up. Have taken onboard the bar-direction subtlety.

Cheers,

Chas.

[cobblerdave]

G'day Chas
I'm " champen at the bit " for this wheather to cool down and stop raining so I can clean up the oven and start cooking again.
It's been a real wet start to the year on the coast, we have had 874mm to date. We average 1200mm a year so we have had heaps early.
The Tuscan grill has had a good wire brushing, new bolt legs and a good coating of veg oil in preparation for those first drying fires.
Regards dave