Friday, June 23, 2017

Monday, June 19, 2017

Primitive Technology: Reusable charcoal mound



*Turn on captions for written commentary (CC in bottom right corner of screen). Charcoal is a valuable fuel that reaches a higher temperature than the very wood it’s made from. I’ve made some before, but with supplies running low due to furnace experiments, I decided to make another large batch of charcoal in a mound. I stacked the wood into a roughly conical shape (about 1 m wide and 75 cm high) and then built a thick wall of mud around the heap (this took 6 hours). Eight air entries were made in the base of the mound and one air exit hole was left at the top of the mound to allow the volatile components of the wood to escape while creating a natural draft to keep everything burning.
The mound was lit and the flame burned backwards down the heap in the opposite direction to the draft. This protects the coal made above the level of the fire from burning as carbon dioxide rushes past instead of oxygen, preventing combustion of charcoal. Each air entry was sealed only when fire became visible through them. This is an easy way to tell when to close them up, i.e. when the fire had burned down all of the wood in the heap. When the last air entry was closed, the air exit at the top of the mound was sealed, 5 hours after starting. The next day when cool, a large arched opening was made in the side of the mound to extract the charcoal. Despite a few unburnt brands the yield and quality was good filling almost 2 baskets.
To see if the kiln was reusable, I restacked it with timber cut from a fallen gum tree branch up the mountain. Due to the difficulty in reaching into the mound I stacked the wood in criss-crossed horizontal layers. The opening was sealed with mud and the mound lit as before. This time the mound burned quickly and I had to seal it early as the timber was burning at different rates, 3 hours after starting. Some large logs remained unburnt while charcoal that had already formed started to burn up being wasted as ash.
When I opened it the next day it had still produced an ok amount of charcoal but was disappointingly low compared to the first batch. This may partly be due to some of the wood being still green though it’s probably more likely to be due to how it was stacked. The lesson here is that when making charcoal the wood needs to be tightly stacked with few air spaces between. If not, the mound admits too much oxygen that quickly burns the timber.
Another thought I had was that wood may convert to charcoal better if laid vertically (or roughly so, like the cone in the first firing) so that the fire starts at the top of the wood and burns down. Stacking the wood in horizontal layers means that each layer has to set the one bellow alight leading to problems if the wood is green (use dry wood if stacking horizontally). By stacking wood vertically each piece is alight already and simply burns down towards the air entries. Stacking in this way also makes it easier to see fire in the air entries letting you know when to seal the mound.
For the reasons above I may make another charcoal kiln in future in the shape of a cylinder with air entries around the base and an open top. The kiln would be re-usable and easily stacked. A conical pile of wood would protrude above the walls of the kiln and be plastered in a temporary cover of mud. The kiln would be fired as with a normal mound and when finished the temporary cover of mud would be removed to extract the charcoal

Friday, April 28, 2017

Primitive Technology: Water powered hammer (Monjolo)




Published on Apr 28, 2017
I built a water powered hammer called a “Monjolo”. I started by making a water spout from half a hollow log to direct water from the creek. This was set up in the creek and water flowed through it. The hammer was made from a fallen tree. I cut it to size by burning it at the points I wanted it cut (to save effort chopping). Next I carved a trough in one end to catch falling water. This was done first with a stone chisel that was then hafted to an L–shaped handle and used as an adze. This adze only took about an hour to make as I already had the chisel head and cordage made of bark fibre to bind it with.
To save further effort carving I used hot coals from the fire to char the wood in the trough. I put the coals in using “chopsticks” (unused arrow shafts) to transfer them from the pit. The coals were fanned or blown with a wooden blowpipe till the wood in the trough burned. Then the char was scraped out. The sides of the trough were sealed with clay to make sure the wooden sides did not burn away which would effectively decrease the volume of the trough. This was approximately 8 hours work over two days.
With the trough carved I made a hole in the middle of the log as a pivot point. Using the same char and scrape method I burnt a hole right through the log using hot coals and a blow pipe. Again clay was used to prevent wood burning where it was wanted. To burn through the approximately 25 cm diameter log it took about 4 hours and 30 minutes. Another hole was burnt in the end to fit the wooden hammer head and it took a similar amount of time.
A tripod lashed with loya cane was set up at the water spout. The axel of the hammer was tied to one leg, the hammer fitted onto the axel and the other end of the axel tied to another leg. The trough was positioned under the waterspout to collect water and the tripod adjusted so that the resting point of the hammer was horizontal (so water wouldn’t prematurely spill out of the trough).
The trough filled with water, outweighed the hammer head and tilted the hammer up into the air. The water then emptied out of the trough (now slanting downwards) and the hammer then slammed down onto an anvil stone returning to its original position. The cycle then repeated at the approximate rate of one strike every 10 seconds. The hammer crushes small soft types of stone like sandstone or ochre. I carved a bowl into the anvil stone so that it would collect the powder. I then crushed old pottery (useful as grog for new pots) and charcoal. Practically speaking, this hammer worked ok as a proof of concept but I might adjust it or make a new one with a larger trough and bigger hammer for heavy duty work.
This is the first machine I’ve built using primitive technology that produces work without human effort. Falling water replaces human calories to perform a repetitive task. A permanent set up usually has a shed protecting the hammer and materials from the weather while the trough end sits outside under the spout. This type of hammer is used to pulverise grain into flour and I thought I might use one to mill dry cassava chips into flour when the garden matures. This device has also been used to crush clay for porcelain production. A stone head might make it useful as a stamp mill for crushing ores to powder. It might pulp fibres for paper even.

Sunday, April 23, 2017

Making Ciabatta Bread






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Ciabatta Recipe

Biga:

Ingredients

3/4 teaspoon dry yeast (I use instant yeast)
1 3/4 cups of cold water
3 1/2 cups all purpose flour (470 grams)

Directions

1. If you are not using instant yeast you should soften the yeast in 1/2 cup of the water first.
2. Mix all ingredients together into a wet batter/dough.
3. Cover and refrigerate for 24 hours.
4. Can be stored in the refrigerator for up to two weeks.

Ciabatta:

Ingredients

1/2 teaspoon dry yeast (1.5 grams)
2 1/2 tablespoons of warm milk (38 grams)
1/2 cup plus 1 1/2 tablespoons of room temperature water. (143 grams)
1/2 tablespoon of olive oil (7.5 grams)
1 very full cup of Biga (250 grams)
2 cups less 2 tablespoons of all purpose flour (250 grams)
1/2 tablespoon salt (7.5 grams)

Directions

1. Stir the yeast into the milk in the bowl. Let stand for 10 minutes. (Not necessary, to let it stand, if you are using instant yeast.) This will work much better if you use weights rather than dry measures. Add the water oil and the Biga, mix until blended. (Use the Paddle if you are using a stand mixer.) Mix the flour and salt together and add to the bowl mix 2 to 3 minutes with the paddle then switch to the dough hook and mix for 3 minutes at low speed then 3 minutes at medium speed. The dough will be very sticky. Turn it out onto a well floured surface and knead briefly adding as little flour as possible. ( A trick that works, if you wet your hand the dough won't stick to them) The dough should start to be less sticky and become smooth and springy.
2. Place the dough in an oiled bowl or air tight container. Let it rise for 1.5 hours at room temperature. (Room temperature is important, not in a warmer area or prover.) After this time the dough should be full of large bubbles.
3. Turn the dough out onto a generously floured board/counter. Cut it into two loaves roughly the same size. Shape each into a cylinder about 10X4 inches, pulling gently to get each loaf about the same size.
4. Place each loaf on a generously floured peel, parchment paper or the back of a cookie tray. Dimple each deeply with your fingers to prevent them from rising too much. Sprinkle the tops generously with flour and cover with a towel and let rise at room temperature for 1.5 to 2 hours.
5. Half hour before baking preheat the oven and a baking stone to 425F.
6. Carefully turn the loaves onto the stone. I bake mine separate the first loaf at 1.5 hours of rising and the second one at 2 hours. The loaf should bake for 20 to 25 minutes and during the first 10 minutes spray water 3 times in the oven being careful to not spray any directly on your baking stone.
7. Cool the loaves before cutting them.