Birch Bark Tar

[jon r]

In the new series of ray mears i hurd him say that birch bark tar was a revolution. But how did people collect it without a modern can on the fire?

 

[torjusg]

In the new series of ray mears i hurd him say that birch bark tar was a revolution. But how did people collect it without a modern can on the fire?

To my recollection, from reading the bulletin of primitive technology, this is one of the great mysteries as noone really has a clue how they did it before the invention of pottery.

I have some ideas on how I will solve that problem, but they are to be considered business secrets for now...

 

[Fenlander]

In the new series of ray mears i hurd him say that birch bark tar was a revolution. But how did people collect it without a modern can on the fire?

I've been doing a bit of research on this one myself Jon.

http://www.ucl.ac.uk/prehistoric/past/past47.html

http://www.newscientist.com/article/mg13718633.100-science-the-glue-that-held-the-roman-empire-together-.html

 

[Diederik Pomstra]

Hello,
Very interesting problem, I've tried it with heating rocks in the fire, putting them in a wooden container with the bark and sealing with horse-dung (this doesn't crack when drying). I got tar, but it was burned on the rocks. Also I've read about a museum in Germany (Oerlinghausen ?) where they made a closed oven of clay, put the bark in, closed it with more clay and let it dry. When dry they built a fire around and on top of it and they managed to get tar. But it wasn't very good quality, it should have been heated longer. That is the difficulty with this method: you can't see the smoke. It works though. On my website there are some pictures of making tar with pottery (www.het-stenen-tijdperk.nl). That works great. I'm curious about your ideas Torjus...
Diederik

 

[Fenlander]

Hello,
Very interesting problem, I've tried it with heating rocks in the fire, putting them in a wooden container with the bark and sealing with horse-dung (this doesn't crack when drying). I got tar, but it was burned on the rocks. Also I've read about a museum in Germany (Oerlinghausen ?) where they made a closed oven of clay, put the bark in, closed it with more clay and let it dry. When dry they built a fire around and on top of it and they managed to get tar. But it wasn't very good quality, it should have been heated longer. That is the difficulty with this method: you can't see the smoke. It works though. On my website there are some pictures of making tar with pottery (www.het-stenen-tijdperk.nl). That works great. I'm curious about your ideas Torjus...
Diederik

Your link isn't working for me I'm afraid

 

[torjusg]

I'm curious about your ideas Torjus...
Diederik

I don't know if they are going to work, but I'll have to wait until spring to do so.

 

[Toddy]

As far as I am aware, a campfire can reach a temperature of 600oC
see this page
http://news.bbc.co.uk/1/hi/sci/tech/3557077.stm

I think that's a bit hot to be honest if not using tuyers but ......
However, I know that if I take a tight roll of fresh birch bark and literally roast it beside the fire then a juicy stuff will exude and drip out into the ashes. This can be rescued as it cools and it's just birch tar with ash and charcoal in it. No need for ceramics at all. It's a bit wasteful but it certainly gives a result.

cheers,
Toddy

 

[torjusg]

And Diederik, There are some of the pics on your site, where thumbnails would be in place...

Would be nice to see them in high resolution as the photos look excellent. :You_Rock_

 

[Tadpole]

Your link isn't working for me I'm afraid

try here link fixed

 

[torjusg]

As far as I am aware, a campfire can reach a temperature of 600oC
see this page
http://news.bbc.co.uk/1/hi/sci/tech/3557077.stm

I think that's a bit hot to be honest if not using tuyers but ......
However, I know that if I take a tight roll of fresh birch bark and literally roast it beside the fire then a juicy stuff will exude and drip out into the ashes. This can be rescued as it cools and it's just birch tar with ash and charcoal in it. No need for ceramics at all. It's a bit wasteful but it certainly gives a result.

cheers,
Toddy

Seems quite slow, but worthwhile to try. Is it as slow as it seems?

Ok, I'm going to burst out my "secret" right away as there already seems to be a solution.

If I understand correctly, the key to making tar is to expose the bark to great heat without oxygen, to avoid that the tar burns. Without pottery this is hard, not to achieve the heat, but to avoid it bursting into flames. Maybe also keeping the temperature lower than the point of ignition also is possible, since you, as Toddy says, can make tar with it being exposed to oxygen.

I have two proposals of possible methods. On both methods you need to roll the bark firmly together first:
1. The roll is tucked into a bladder (to contain the tar) and is buried in the sand under a flat rock beneath the fire. A hollow reed is stuck into the bladder at one point and it goes out of the ground on a different place than the fire. Maybe a metre away.
2. The roll is placed in a rock with a natural depression (avoid much air around the bark), a flat rock is placed on top and a fire is lit there.

Don't know if any of them would work, but they may be worth a try.

 

[Diederik Pomstra]

OK! Sounds good Torjus, let me know if these methods work. But I think I'll try Toddy's method first: it feels very hunter/gatherer-ish: straightforward and effective. My only problem is that I need birchbark.
Sorry about all the website-things, I'm not too good at that kind of thing.
Thanks for the inspiration!!
Diederik

 

[clcuckow]

Not tried this before and it is just a thought what about digging a hollow and maybe lining with clay. Next in the bottom put a tight birch bark cigar in the bottom and fill the hollow with ash and build small fire on top. That should keep the O2 down and I would have thought that the ashy tar would pool in the bottom.

Just a thought.

 

[torjusg]

Not tried this before and it is just a thought what about digging a hollow and maybe lining with clay. Next in the bottom put a tight birch bark cigar in the bottom and fill the hollow with ash and build small fire on top. That should keep the O2 down and I would have thought that the ashy tar would pool in the bottom.

Just a thought.

That would probably work, but you'd need to be close to the coast, where there is good clay.

 

[clcuckow]

That would probably work, but you'd need to be close to the coast, where there is good clay.

The clay way only idea to aid pooling and to stop it soaking into the soil. I would have though that flat rocks would also work. Again it was just an idea on how to keep the O2 down in the same way you do for hardening wood and when baking potatoes etc.

I have quite clayey soil in the garden so I might give it a go one day.

 

[match]

I was just pondering this - and wondering whether its at all related to the water content of the wood.

Toddy's point about the sap coming out of the wood when placed ina fire is certainly true, but I've noticed that you tend to see it more if you put really damp wood onto a very hot fire - the water presumably turns to steam/builds pressure inside the wood and drives the melted sap out.

Maybe soaking the wood well in water first would drive out the sap while keeping it and the surrounding wood damp enough to prevent oxidation?

(and yes, for anyone wondering, I have been very lazy recently and this is my first post in aaaages )

 

[torjusg]

You can't use wood, Match. You need birch bark. But your idea may work. I would assume using fresh bark would be better than dry anyway.

 

[match]

Sorry, I was meaning use the wood with the bark on - if you can soak and heat the wood the steam etc driven out of the wood has to pass through the bark, possibly carrying the sap with it?

But yes, stripping off the bark and then soaking that might also be an option.

 

[torjusg]

Sorry, I was meaning use the wood with the bark on - if you can soak and heat the wood the steam etc driven out of the wood has to pass through the bark, possibly carrying the sap with it?

But yes, stripping off the bark and then soaking that might also be an option.

I don't think that will work. The steam will more than likely go out through the ends. Birch bark is pretty water proof stuff.

 

[Don Redondo]

torjusg's idea of the two flat rock appeals... because this might of been how the tar was 'discovered' in the first place...

Is'nt there evidence, or at least a hypothesis that metallurgy was 'discovered' and developed from the chance event of a copper rich stone being placed near to a campfire hot enough to melt the vein of ore?

very often the 'simplest' reasons are the best ones.... two hot stones, loads of ash sealing in the heat... and a curious hunter the following day, wondering what the black gunk at the bottom of his firepit was, and making that leap of intuition.

 

[jon r]

I have a small paint can with a whole in the lid. This is packed full of birch bark and then the lid is tightly put back on. Then i dig a whole where my fire is going to be and put a baked bean can in it. Then i turn the paint tin upside down and put it ontop of the submerged baked bean can. Once thats all done i build my fire around and ontop of the paint can. Then when the bark gets hot enough, the tar drips through the whole in the lid into the baked bean can. Last time i did this there wasnt much to show for my efforts and the tar never set! oh well, live and learn!

How do you collect your birch tar? (talking to everyone in general)