Fulacht fiadh - tannery

In my last post "Fulacht fiadh - meat and fish curing facility" i said that fulachta fiadh were also called Fulachta Fian and were believed to be the cooking place of the Fianna, small, semi-independent warrior bands in Irish mythology. I also said that Geoffrey Keating, in his 17th-century History of Ireland, says that during the winter the fianna were quartered and fed by the nobility, during which time they would keep order on their behalf, but during the summer, from Beltaine to Samhain, they were obliged to live by hunting for food and for pelts to sell.

As I said in my last post, this was very interesting. If Fianna were "obliged" to live by hunting for food and for pelts to sell, they were basically full time, professional meat and fur hunters. Professional seasonal hunters have two problems that they have to solve if they want to profit from their hunt: How to preserve and store meat and skins. 

In my last post I talked about how the ancient Irish could have solved the problem of preserving and storing large quantities of fish and meat. 

In this post I would like to talk about how they could have solved the other problem: how to preserve and store large amount of animal skins and furs they would have accumulated during their seasonal hunt. 

The process of preserving animal skins aims to make animal skins resistant to bacterial decomposition and weather. This process is quite complicated and consists of many steps which have to be performed correctly and in strict order or the skins will be spoiled. 

I will here list these steps, based on an instruction for deer skin preservation process from the Wilderness Institute web page. And I will explain how fulachta fiadh could have been used in this process. 

Skinning

Hang the deer upside down to a branch. Cut the belly open and gut and clean the animal. Cut the around the hocks and then along the legs from the hocks to the beely cut. Put the knife away and removing the hide with a fist, not a knife. This is to prevent any knife or score marks on the hide. Score marks now will become holes later. This is a very good video showing how to skin a deer using this technique. 

Fleshing

Remove any meat and fat from the hide using scraper. You can use a metal scraper (a blunt long blade). Traditionaly a bone scraper made from a deer ulna bone was used. 

Salting

Salting is what sets the hair and keeps the hide from decaying. The moisture content of hides and skins is greatly reduced, and osmotic pressure increased, to the point that bacteria are unable to grow. There are two ways of salting the skins: wet salting and brining. 

But theoretically, all hides are brine cured. Crystalline sodium chloride, or common salt, cannot be absorbed by the hide. Only after the salt crystals have been dissolved in water to make a brine can the curing proceed. In the case of the conventional method (pack curing), the salt crystals draw moisture from the hide which dissolves the salt creating brine. 

In wet salting, the skins are heavily salted using fine salt by rubbing the salt into the inner side of the skin or hide. After salting, hides are rolled up and placed on an incline to allow fluids to drain away from the hide. After approximately 12 hours the skins are unrolled and all of the wet salt is shaken off. A new layer of fresh salt is applied to the skin as explained above. Skin is rolled again and left to rest for additional 12 hours. If after these 12 hours, the skin still appears excessively wet, the salting process is repeat again. If however the skin appears to be drying, with no more fluid draining from it, it can be hung up across a rack to finish drying for another 24 hours.

In the brine curing process, the hides are in contact with saturated brine at all times. This serves to reduce the time required to cure hides to about 16 hours. The hides have to be constantly turned and agitated to ensure that every part of the skin is properly soaked with brine.  

Both of these salting methods would involve use of fulacht fiadh. 

If wet salting was used, salt was probably grabbed from leather sacks or pots where it was kept and then applied to the skins by rubbing. The excess salt which was brushed off the skins at the end of each salting stage, could then have been collected and eventually purified and reclaimed through boiling in the trough using fire heated stones. 

If brining was used, brine was made in the trough. Different size skins require different size troughs to insure the skin was completely submerged and not tightly folded. This could account for great variety in fulacht fiadh trough size. At the end of the brining process the remaining salt could have been reclaimed from brine  through boiling in the trough using fire heated stones. 

This of course could only have been possible providing trough was made watertight. If not the brinning solution would either be diluted or chemically changed by influx of water from the soil, if the fulacht fiadh was located on marshy, waterlogged terrain, or the brine would disappear into the ground if the fulacht fiadh was located on dry well drained soil. 

At the end of the salting procedure, if the above steps were followed and completed carefully, the skin should be in a stable state. A stable state is when the skin can be safely left as it is for a period of time, even months, without fear of hair slippage or spoilage. This means that the process of preserving the skins can be interrupted at this point and continued at some later more suitable moment, like during the winter, after the end of the hunting season. 

It is quite possible that this was the end of the animal skin treatment process which was performed in summer camps. The skins would be salted and stored safely in a tent or in a wood lined pit dug in the well drained ground. They would then be carried to the village where the rest of the skin preservation process which turns skins into leather and pelts was carried away. 

There is one thing I have to add about salting. Salting is not a mandatory part of the animal skin preservation process. Salting is used in cases where there is a long enough period between the skinning and the rest of the skin processing. Bacteria in the skin will start decomposition pretty much straight away and even if only couple of hours have passes between skinning and the next processing stage you will be better off using salting to make sure the decomposition was stopped. But if you are going to flesh and wash the skin straight away after skinning, then salting is not necessary. You can basically just wash, stretch and dry the fleshed animal skins completely. You can then store these dry skins in a dry airy place for months until you decide to continue the skin preservation process. This is very important. As I already explained in my post "Fulacht fiadh - salt pan", salt was a rare and valuable commodity in ancient Ireland and I doubt the Fianna hunters would use salt for treating animal skins unless it was absolutely necessary. 

Now next stage in animal skin preservation depends on whether you want to produce leather (hareless skin) or pelts (hairy, furry skin).  If you want to produce leather, then the next thing you need to do is bucking followed by rinsing, graining and membraning and then rinsing again.

Bucking

"Bucking" is the soaking process in the solution of lime or lye (wood ashes) the hide is soaked in to remove the mucus in the collagen layer of the hide, as well as to loosen the hairs. It's the mucus that prevents the tanning medium from adhering to the fibers in the hide. You have to make sure that the bucking solution is not "too strong" which is possible with hardwood ashes, especially with ashes from woods such as oak and maple (the hard, dense woods). A good way to test how strong an ash solution is: float an egg, it should have a thumb nail sized portion floating above the solution (it has to actually float, not sit on top of the settled ashes); barely floating means a weak solution, tipping over means a strong solution.  

So mix wood ash into the water, float an egg to determine proper concentration of hard wood ash, then soak hide until hair slips. The skin should soak until the hair pulls free easily. If the water is about 20 degrees Celsius it should slip in about 3 days. 

This is another part of the animal skin preservation process which could have been done in fulacht fiadh. A trough would be filled with water. For this to be manageable fulacht fiadh would need to be located next to a water source, as they all are. Ash from camp fires would then be added to the water and mixed in to form bucking solution. When bucking was finished, remaining bucking solution could be scooped out of the trough using cups or pots and spilled on top of the burned mound. Or the water could have been evaporated from the trough using fire heated stones, and the ash then scooped out. 

Again, this could only have been possible providing trough was made watertight. If not the bucking solution would either be diluted or chemically changed by influx of water from the soil, if the fulacht fiadh was located on marshy, waterlogged terrain, or the bucking solution would disappear into the ground if the fulacht fiadh was located on dry well drained soil. 

Graining

Graining means removing the hair and grain, the part of the skin that holds the hair. Any grain will make the hide stiffer and will prevent the smoke from entering the hide when smoking the hide latter on. This means you are scraping the outer side of the skin. Traditionaly a bone scraper made from a deer ulna bone was used. It works great but must be sharpened through out the process. 

Drying Skins

After the hides have been grained set them in the sun to dry. This should not take any more then an hour on a dry day. This drying will make the membraning much easier and productive.

Re-hydrating

Dunk skins into a river or a stream to get them thoroughly wet. Another reason why fulactha fiadh would need to be built next to rivers or streams. This should not take more then about 15 min.

Removing the membrane

By the way bucking also works on the inner side of the skin softening any remains of meat, membrane and other tissue left after skinning. So during graining you can revisit the inner side as well and remove what ever was left clinging to it.

Using the fleshing tool remove the membrane which is what holds the blood vessels. Like the grain, if any membrane is left the hide will be hard and will prevent the smoke from penetrating the hide. You are now working the inner side of the skin. This part of the processing is done as part of fleshing if you want to produce pelts and not leather. 

Rinsing

After the membrane has been removed, put the skins in a gunny sack tied off in a river or a stream and leave them overnight. Again it is handy if your camp is next to the river or a stream...

Wringing

Next morning the skins should be thin. Wrap the hide so it forms a donut with the outside of the skin out. Wring in one direction then the other, then rotate the hide and do it again. Do not let the dry out you want the skins thirsty but not dry.

Opening (stretching) the skin

Opening the skin will make the skin be thirsty and will do a better job of taking up the tanning agent. 

At the end of this part of the process we have so called "stable" skins, skins which can be stored indefinitely and even used inside where they are not exposed to the elements. They can be smoked to be made more durable and resistant to bacteria and insects. But if you want your skins to be resistant to water and not go cardboard hard ever time they get wet, they need to be tanned, oiled and softened and smoked.

Tanning

Here you can choose which tanning solution to use to tan your skins. Four traditional and tanning processes that have been used for thousands of years in Europe are vegetable (wood) tanning, brain (oil) tanning, urine tanning and bran (flour) and salt tanning. 

Bark tanning

Tannins are chemicals, more precise acids, which occur naturally in most plants in various amounts. They transform proteins into insoluble products that are resistant to decomposition and this is why tannins are used as tanning agents for leather.

Tannins occur in nearly every plant. It is found in almost any part of the plant, from root to leaves, bark to unripe fruit to nuts and acorns, but it is most concentrated in the bark layer where it forms a barrier against microorganisms such as fungi and bacteria. Typical materials used for bark tanning include any of the oaks, fir, certain willows, chestnut...

If you want to use bark for tanning extract it is best to collect it in the spring. This is when the bark has the highest concentration of tannins and is the easiest to peel, but you can use bark from any time of year. Supposedly, an older tree has more tannin than a younger one, and the lower parts of the tree contain a higher concentration than the top parts. 

Now getting the bark off trees, even if you don't cut the tree down, will kill the tree. It is good then to know that you can extract tannins not just from bark but also from acorns, oak galls and even leaves (as you can see in this video). 

How do you extract tannins out of the bark? You leach them out. You dry the bark, crush it, pound it into a pulp and then cook it. Tannin is water soluble. The warmer the water you soak the bark in the faster the tannin is extracted. But hot water darkens tannin resulting in a darker colored leather. Now remember my post "Fulacht fiadh - acorn leaching pit"? What i described in that post was a way fulacht fiadh could be used to leach tannins out of acorns. Basically you would fill the fulacht fiadh trough with water, heat the water using the fire heated stones, then dump a lot of shelled and crushed acorns into the trough, and keep simmering them, occasionally changing water until all the tannins were leached out and the water is finally clear. Here you can see what tanned water produced by leaching acorns looks like.

The same leaching procedure can be used for extracting tannins from barks. The tanned water which results from this procedure can be scooped out of the fulacht fiadh trough and collected in large clay vessels. It can then be boiled and concentrated. The concentrated tannin rich "tea" can then be poured back into the trough and used as tanning solution for animal skins.

Soaking of the skins in tanning solution should be done first in a relatively weak solution and then in progressively stronger solutions. It is very important to use a very weak solution for your first bath. If the hide is put into a strong tannin bath, the outside gets tanned and shrinks. This inhibits the tannins from penetrating to the center of the hide, leaving the inner parts raw. This is called "dead tanning" or "case hardening". The ideal bath to start with is one that has already been used for another hide. That way all the large tannin particles have already been used up. This is known as a "spent liquor". There is another advantage to spent liquors. In an old bark liquor, the bark sugars have fermented, forming lactic and acetic acid, which help remove any traces of lime as well as help preserve the hide. 

The skins should then be left in the strong solution for as long as it takes for the solution to penetrate all the way to the center of the skin. But how long that is depends on the thickness of the skin and can go from few weeks to few months. Here you can see skins submerged in the tanning pit and the pile of oak bark next to the pit, used to make tanning liquid. Fulacht fiadh trough uses for skin tanning would look very similar to this. 

During the soaking period, fulacht fiadh trough containing skins submerged in tanning solution can be covered with planks or split branches and then covered with hide and soil or peat. From time to time it can be checked on and more tanning concentrate or raw bark can be added to strengthen the tanning solution. 

Eventually the skin is taken out of the tanning solution. It then needs to be rinsed in running water (river, stream next to which fulachta fiadh were usually built) and squeezed and rinsed and squeezed...Until it is rinsed I suppose. :)

The skin then needs to be oiled. Oiling the bark tanned skin makes it dry softer, darkens it and prevents it from cracking. Vegetable oils (beach nut oil), tallow, brains, bear and boar fat and fish oil have all been used to finish bark tanned leather. The hide that is being oiled should be damp. It should then be stretched in all directions. Oil should then be spread evenly on the skin and the if you want soft leather the skin should be worked soft as it dries. When the hide is dry, it can be lightly dampened and then oiled and worked again. This process of oiling, working and drying can be repeated until you get the softness you desire. 

This is a good video showing primitive bark tanning of animal skins. 

Brain tanning

This is truly ancient tanning method. It is quick and well suited for single skin processing in the wild. And as opposed to bark tanning it is environmentally friendly. 

There are two distinct methods of brain tanning, one in which you apply tanning solution onto the skin and the other in which you soak the skin in the tanning solution. 

Making the brain solution

Every animal has enough brains to brain tan its own hide. Except for buffalo for which you need brain and bone marrow. To prepare brain tanning solution use warm water but not too hot.  A good rule of thumb is that if its too hot for you, its too hot for the animal. Too hot will ruin the hide.  You have to mix the brains from the animal into warm water and mash them up into a paste. 

Applying the brains

The biggest trick to good brain penetration is proper hide moisture content. You want the hide damp in that you can not squeeze and moisture from it, but feels like a sponge. Too dry and the pores will be too tight to let the brains through, too damp and the pores and fibers will be too full to let anything else in. 

Rub the brain mixture into the stretched hide until it is thoroughly saturated and soaked in. If you are treating hair on hide, make sure you only apply brain solution on the inner side of the hide, as it will make the hair slip if applied on the outer hairy side. Wait until the skin almost dries, then apply the brain solution again. Wait until skin dries again. Remove it from the frame and soak it in water again and then wring it out. Stretch it on the frame again.  

This series of videos shows how to brain tan a bear on a frame. This part shows applying brain tanning solution on the skin stretched on a frame.

But the skin doesn't need to be stretched on the frame for brains to be applied to it. This is a very good series of videos showing how to apply brain solution on a skin stretch flat on the ground.

Softening

After the skin has completely dried out, it needs to be softened. This is done by simultaniously stretching and rubbing the skin. If the skin is stretched on the frame, the softening is done by pushing and scraping the hide with a blunt stick. You have to make sure that every bit of skin is pushed and shoved and scraped... 

Otherwise you can use a pole, a tree stump, a rope or anything else that you can stretch the skin over and pull it from side to side. Here you can see softening of the hide on a stump. 

Regardless how you decide to soften the hide, you have to keep the hide in motion stretching, pulling, pushing for a very very long time. This is a hard process which is continued until the hide is soft. If it gets hard in any places it is because those places dried without being in motion. Rehydrate that part the skin and continue to soften it until it is dry and loose.

Smoking

In order to make a brain tanned hide resistant to water, it has to be smoked. Otherwise the hide fibers would glue themselves back together again and the hide would become hard. The resins in the smoke penetrate the hide and prevent them from gluing them back together again if they get wet.

Smoking of hides is identical to cold smoking of meat. You need to place the hide on some kind of frame over a smoldering file. If you are smoking one hide or few hides you can just make a temporary tripod from sticks and spread the hide over it, inner side in. 

Then you place the tripod over a fire. This needs to be a cool smoking fire made with punkwood. Punkwood is the wood from any tree that is in a stage of decay where it feels almost styrofoam-like in consistency… very light and slightly squishy.

You have to make sure that the smoke rising from the fire is cool and damp. If the smoke starts to feel dry add more punkwood. It the fire stops smoldering and starts to flame the hides will be ruined. Hides will need to be smoked like this for several hours. Or you can hang the hides under the roof of your wigwam or round house and let them smoke over constantly smoking heart fire. As I already wrote in my post about Curing = Smoking, this is probably how the curing ability of smoke was originally discovered. After the smoking is done, the brain tanned hide will be water resistent. 

Urine tanning

In ancient history, tanning was considered a noxious or "odoriferous trade" and relegated to the outskirts of the town, among the poor. This is because Old Mediterranean and Messopotamian cultures for some reason thought that the best tanning agent was urine. And poo. 

Is this why there are no fulachta fiadh inside villages?

Urine tanning is one of the oldest tanning methods. And one of the stinkiest. Urine tanning consists of dunking skins in a half - half mixture of water and urine and leaving them to soak for a period between 1 day (Source: "Leather - Preparation and Tanning by Traditional Methods" by Lotta Rahme) for fish skins to 30 days for hides with fur. 

Why use urine? Urine contains ammonia, and ammonia is an amazing basic solvent that can break down fats and oils, clean surfaces and stop decay from forming. When our bodies and the bodies of all mammals break down amino acids as a part of normal metabolism, we produce ammonia. Since ammonia is toxic to us while in our bodies, our livers covert that ammonia into urea and salts, which we excrete in our urine. But that separation is only temporary. If you leave the urine to lie around for any amount of time, the urea and salts will start binding back together to form ammonia again. This is why it is the stale pee that is used in tanning.

In order to tan skin with urine, you need to have enough urine to completely submerge the skin in it and have it float without being tightly pressed. Basically what you want is that every bit of the skin is in contact with urine water mixture. For a salmon skin or a small animal like squirrel this means 4 - 8 liters of urine per skin. For larger animal skins you will need a lot more. Normal daily output of urine for an adult is one to two liters per person. So a group of 10 hunters would be able to collect say average 15 liters of urine a day. If an average fulacht fiadh trough contains about 200 liters, they would need 80 liters of urine to make 160 liters of urine water mixture and fill the trough. To collect this volume of pee would take about a week. And where you might ask yourself would the fianna collect their pee in? Well how about the fullacht fiadh trough...Every morning fianna members would emerge from their camp shelter, bloated from all the fulacht fiadh brewed beer they drank previous night. They would gather around the fulacht fiadh trough and then....

As I said, I would take a 10 man hunting band a week to 10 days to fill the trough. During that time they would skin killed animals, flesh and membrane the skins, rub them with urine or mixture of ash and urine to help get rid of hair (if they were making leather rather than pelts) and would then grain the skins wash them and dry them in the sun. These stable skins would then be stored in one of the shelters until the fulacht fiadh trough was full of pee. 

Collection of urine for tanning is well documented, The so called "piss-pots" were located located on street corners, where human urine could be collected for use in tanneries or by washerwomen. So theoretically our fianna boys could have collected new urine in large beakers :) while the skins were pickling in fulacht fiadh trough full of old urine. This way there would be no pause in the trough use...

Once the trough is filled the skins can be then be submerged in the tanning solution and left there until they have been properly tanned. After the skins are submerged and stirred the trough should be covered with hide pressed with stones to prevent excessive evaporation of ammonia. 

You'll check the skin every day and give it a stir.  It shouldn't smell too awful, and if it does, you need fresh solution because bacteria has set in. I couldn't find any instruction how do you distinguish between awful and too awful...I guess years of smelling old pee baths filled with decomposing animal skins will teach you....

Once curing is finished, the skins need to be taken out of the trough. The trough would then need to be emptied of used pee water solution, as it should only be used once. And the new cycle of pee collection would start. As for hides, they would need to be thoroughly washed in water. Few times....It helps if its rubbed in with soap and then rinsed several times. Ancient Irish could have used soap made from camp fire ashes and animal fat. It is also possible to make a warm solution of soap mixture in water, let it cool and then soak the skins in it. You can then make a scented solution of strong smelling barks and flowers in water (tea) and then soak the skins in this water...North American Indians used this type of skin washing procedure after pee tanning. However, even after all this washing, the skin will stink like old pee when wet but as it dries that smell will go away. However some people say that it is the stink that goes away but the smell never really goes away...

Anyway, smelling or not, washed skins would then need to be dried properly. After that it would need to be oiled and stretched and softened. The urine tanning leaves skin very pale. So If you want to change the color of the skin, you can then tan it using vegetable tannins. And then smoked. And that is it. 

Again, the use of fulacht fiadh trough as a tanning vat, could only have been possible providing trough was made watertight. If not the tanning solution would either be diluted or chemically changed by influx of water from the soil, if the fulacht fiadh was located on marshy, waterlogged terrain, or the tanning solution would disappear into the ground if the fulacht fiadh was located on dry well drained soil. 

Bran (flour) and salt tanning

I came across another very interesting way of tanning pelts, which is not very well known: wheat (oat) tanning. This type of tanning was in Scandinavia used to tan sheep skin rugs, and in Serbia, Romania and probably other places for tanning sheep skin for coats. This is how you do it:

Scandianvia

Two handfuls of flour and one handful of salt was rubbed into the fleshed and membraned inner side of the skin. Then the skin was folded, a weight is put on and it was then left in a dry place to set for three days. After 3 days, the flour and salt were scraped off the skin and skin was stretched and broken until soft. Finished!

A skin treated like this will be white and relatively brittle. The Scandinavian rugs where used mainly as bed covers, if kept dry, they could last for a lifetime and more.

Romania

The process of tanning sheepskin was practiced by most of the peasants at home, with traditional techniques.

Boiled salty spring water (brine) was let to cool down. Oat flour and wheat bran were added, while stirring. The sheepskins were then treated with this mixture and folded, for 3 days. After 3 days, they were dried, then cleaned and stretched and softened.

Serbia

In Serbia salt and flour tanning is done in two ways: dry and wet. 

Dry tanning

Stretch well washed, fleshed and membraned sheepskin or fur. Rub mixture of flour (bran) and salt into the inner (flesh) side. Leave the skin to dry in a draft our of the direct sun. Once the skin is completely dry tanning is done. The sheepskin or fur is then scraped, brushed and worked to soften. 

Wet tanning

Bran and non ionized salt are poured into luck-warm water (40C) and is left to ferment for 3-4 days. You need 50 - 60 grams of bran and 70 grams of salt per liter of water. Once the tanning solution was ready, skins were submerged in it and left soaking for 1 to 2 weeks. After tanning is done, skins were taken out of the tanning solution, washed, dried, scraped, cleaned, brushed and then stretched, worked until soft. Metal containers and utensils react with salt and rust and should never be used in this type of tanning. So wooden tubs and wooden spatulas or sticks were traditionally used. 

This second procedure could have easily been used for tanning furs in fulachta fiadh. 

Fulacht fiadh troughs which were lined mostly with wooden planks and sometimes with stone plates are ideal containers for this type of tanning. For a 150 liter container (1 meter X 0.5 meter X 0.2 meter), which is an average size fulacht fiadh trough, you would need about 8 kilos of bran and about 11 kilos of salt. To prepare the tanning solution you could pour water into the trough and then heat it using fire heated stones. Once the water is cool enough to put your hand into it, bran and salt could be poured in and stirred. This bran soup would then be left in the covered trough for 3 - 4 days to ferment. The furs were then submerged in the through and pressed with logs so that they don't float on the surface. The though would be covered again and furs would be left in the tanning solution for one to two weeks. They would be stirred and mixed from time to time to ensure that every part of the skin was in contact with tanning solution. When the tanning was finished, furs would be taken out, dried, scraped, cleaned, brushed and then stretched, worked until soft. The salt still remaining in the tanning solution could be reclaimed by dropping fire heated stones into the trough and boiling the water out. 

After tanning skins were unintentionally smoked. This type of primitive tanning was done by peasants and they lived in very smoky houses with no chimneys. Like this one from Croatia. 

Any skin worn or in any other way used in such houses would soon be completely impregnated with smoke resin and made resistant to elements...

This is a brilliant video showing traditional sheepskin tanning performed by three grandmothers in a village in Croatia. They actually only use salt as a preservative agent, but the procedure is the same as in salt + flour tanning. 

Now we know that Bronze age Irish did grow grains, so they could have used either one of these methods for tanning furs using mixture of salt and bran (flour). By the way this is a very environmentally friendly way of tanning. 

So, there you have it. Geoffrey Keating, in his 17th-century History of Ireland, says that during the winter the fianna were quartered and fed by the nobility, during which time they would keep order on their behalf, but during the summer, from Beltaine to Samhain, they were obliged to live by hunting for food and for pelts to sell. If the Fianna really lived from hunting for pelts to sell, they had to be able to turn animal skins into durable, useful and good looking leather and pelts. To do that they had to preserve (tan) the skins.  And as we have seen Fulachta fiadh could have been used as efficient tanneries (providing troughs were made watertight).  So was this one of the usages of fulachta fiadh?