Finnish masonry heaters. -The baking oven. Part 2.

Ok, Part 2 and here I will show a few more advanced techniques for heating the baking oven. I will do a complete burn cycle and monitor the temperatures for 48 hours showing the temperature hour by hour. Note that the oven is still giving heat long after the 48 hours is over but I had to cut the monitoring short for reasons described in the video.

Hope you find the video interesting!

At the one minute mark I say that there will be an onscreen link but for some reason the link does not show up! tried to fix this multiple times but it is still not working.

If you have not seen part one…here is a link.

There is also a working link at the end of this video.

Hello again and I say again because this is part two of the baking oven videos in part one I’ve shown the basics of the of the oven where the channels go and I did one full burn this time I’m going to be showing um in a little bit more detail

How things work and a little bit more advanced way Advanced system for for heating it to get the maximum out of it so I will light this and I will document hour by hour how the temperature goes um I’ll also document alongside that the temperature outside and the

Temperature in the room and then I have a thermometer here which is measuring the temperature of the brick work which is the important thing with this okay let’s get going if you haven’t seen part one then the link is on the screen now now I recommend that you go and watch that

First so why am i showing you two ways to heat this thing if there is a more efficient way to get more heat out of it then why is there another way and there are there is an answer to that firstly um the way that I showed you in part one

Is great if you’re going to light the baking oven and then go off to work come back and you can close the baffles and you know you heated for the next couple of days but I think the the more logical reason the reason I think that they’re built this way is that traditional

Finnish rye bread once you mix the flour with the Ry starter because they don’t use yeast and mix that you then leave it to to stand or prove for 5 hours and then you take it out and eat it a bit and then it proves for another

2 hours so you could light the baking oven in the morning start doing your rye bread dough and through the course of the day you get that ready and when it’s ready to go into the baking oven the baking oven is ready to close and you can just slide it straight in

There whereas the method I’m going to show you now takes a little bit longer but it gets the oven hotter so you can cook other things it’s not just for baking at that point and it does as a side effect um get the maximum amount of heat production to to keep the house

Warmer for longer okay so let’s get to it the first thing is that once the fire has really got going there’s a really good fire going I close the air right the way down not completely shut but pretty close to it now I don’t pretend to know why this

Works but it must be something to do about the heat moving slower through the brick work but it seems to to mean that the bricks take in heat faster at this initial stage if you remember from part one it was an hour and a half before the bricks actually registered any temperature

Difference whereas with this method after the first hour the bricks are already showing a 9° increase so it’s not much but after after the second hour already up to 50 so it just kickstarts the the transfer of the heat into the Bricks now I know what people are going to say that by reducing the amount of air going into the nest then I’m creating an inefficient burn in there I’m sure I can hear the the voices of the the rocket stove people already but okay it may be an

Inefficient burn but at this stage when the fire is roaring and a lot of that Heat’s going up the chimney I think what’s more important is the efficiency with which the heat sinks into the bricks and this seems to work it makes a difference now there is the

Law of diminishing returns involved here and it only seems to make a difference in the first about 3 hours of burning so after 3 hours I then opened up the the air to the pessa to the nest I’m also aware that the less than Optimum burn for a few hours means

There’s going to be more suit and deposits but I’m not worried about that the the baking oven has itself six cleanout ports which are cleaned regularly and the chimneys are swept twice a year so not an issue So it’s worth remembering now as we hit the 7h hour mark that this is the stage when I did the ordinary burn of the baking oven that the fire was already out and I was ready to close the baffles in this instance we’re still going and the temperature hit

119° now at 7 and half hours that went down to 118 so I decided that we’d peaked so it was time to close the baffles on the baking oven which I did don’t worry it’s not as simple as that I couldn’t just close the baffles and leave the fire burning let me

Explain so the temp temperature is now at 118 it was at 119 so we’ve got to the top and this is where there’s the biggest difference with this second method of heating this up what I’m going to do is I’m going to take all the coals that are now in there

That’s all that’s there anymore it’s just coals and I’m going to shut them down the whole in the front left corner of the fire Nest I’ll show you that hole so while I do that let me explain what’s going on first I just have to recap something

That I went over in the first video and and here we’ve got a crosssection of the baking oven where you can see the Firebox or what I call the nest and the channels going up from that um which then combine and go across to the right into the wall of the

House and once in the wall of the house they go down all the way to the floor they go halfway back and then they go up the chimney but as I said in the first video there is a second chimney so all the coals are now down in that

Hole I now close the bottom chamber off shut off the air intake and I think I’ve just broken the thermometer and I close the baffles now you’re probably thinking you can’t close the baffles carbon monoxide but let me explain so down below the Firebox through that Port there is a secondary

Chamber and that chamber has its own baffle so you put the calls down there close that baffle and then there is a small Channel running from that chamber all the way to that second chimney working and it’s 126 so the temperature is already going up

And last time I heated it you will seen if you saw the first video that um once I closed the baffles the temperature started really going up quickly and what we’ve done here is we’re getting that bump in heat right when the baking oven is at its hottest and that’s just when

Those coals are like that so we’re at 135° there it’s about 5 minutes since I put everything down below so in the first video I showed the drawing of the baking oven and where the nest the fire Nest is but below that there’s a secondary chamber there’s a chamber

Under here and that hole in the front left of the nest goes down there it has its own baffle so you open the baffle put all the coals down there and then close it now the reason that’s not a problem with the carbon monoxide this has its own clearing output here is

That this bottom chamber has its own ch panel which links up to the second chimney at the back of the the baking oven now the standard size of the flu or chimney here in Finland they’re all this size is half a brick the channel that goes from this bottom

Chamber is a little bit less than a third of a brick it’s a tiny little Channel but at this stage when it’s justs it’s not giving off lots of lots of smoke and gases and stuff like in the middle of the burn it needs that big

Chimney to get all the stuff moving when it’s down to coals there’s not much coming off so that little chimney is enough and so the coals come down here they continue to give out heat and start heating this the bottom of the baking oven and the carbon monoxide is getting

Drawn off through that second chimney which allows the whole baking oven to really start start um sucking all the heat out of the gases that are now trapped in this top area and we managed to do that because of this we managed to do that at the point when the the

The where everything is at it’s Hottest So with both the method shown in the first video and the one second shown in the second video we ended up closing the baffles off at the about the 7h hour mark But the difference is with the second method we can then cook at a much higher temperature and the house is

Going to stay hot for a lot longer now if you weren’t going to cook there is a second method to do this um to be honest I don’t use the method but I’ll let you know just so so that you know you may have noticed that when I close close the

Baffles there are two baffles and I close the baffles now the lower baffle has a hole in it and that means that once you got to that 7h hour mark and you judged that the that the you’d hit the top temperature you could close that lower baffle and again you’re left with a

Little hole that where the carbon monoxide is going to get drawn up I don’t use it cuz I’m a bit paranoid about the carbon monoxide obviously I’ve got a carbon monoxide detector but that’s just a method I don’t use and so it continued the temperature the brick temperature on the baking oven

Gradually drops but the room temperature stays pretty even do bear in mind this is the temperature the bricks on the Brick Oven um not the oven itself which is significantly hotter and here we’ve got a good point of reference the the temperature at 24 hours in the first video was 90° and

Using this method we’re at 110 now I had to stop monitoring temperatures once we got to the 48 hour mark in the first video in the simple method at the 48 hour marks I think it was around about 40° that we got to now the reason I had to stop this time at

For 48 hours is that in a couple of days time we’re expecting temperatures outside to get down to about -23° which is – 9.4 F so I’m going to have to heat up a couple of the other fireplace in the house to get the house warmed up ready for that now interesting

One of the other fir places that I’m going to be heating up is this one and this is a really interesting one in fact it’s interesting enough that I think think I might have to do a video on it it’s effectively a kind of a rocket stove but what the rocket stove people

Will find interesting is that it seems that rocket stoves rocket stoves did not arise in the 1980s because these ones were being built in Russia in the late 1800s so if you think that might have be of interest to you then please subscribe and you’ll get a notification when I

Post new videos and new projects thanks for watching and I really hope that this information helps Somebody