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Franco G. Aitala
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La Carbonaia


The title of the English prose is in Italian, trying to achieve some suspense about the dry technical content. The Switching from present tense to past tense and vice versa was intentional. Keep your water pails handy, this is a hot subject.....

I beg your indulgence.....

Franco G. Aitala
Pennsylvania, USA
6:13:00 PM 7/24/99

The carbonaia was no more. The dry field ( prato) where it had stood, a proud monument to my father’s ambition and a novelty to the schoolchildren, was marked by a raised spot of hard burned clay.  A black charcoal disk marked the spot where it had stood. It slowly.released thin layers of grayish cinders to the summer breeze.

“Bring a fascina (bundle) of wooden sticks,” my father told the fifty children in his class in a clear but accent less Sicilian voice, “except the little ones!”

“Yes, we are going to make charcoal!”

So every day they trundled to the white two story school in Vranici, proudly carrying round bundles of tondelli. It was a great excuse for the older boys not to wear their black uniforms (grembiali) and the white collars. The girls in my mother’s class crowd the three windows of her classroom and rub their forefingers in unison to challenge the boys' chore.

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“Cica, Cica!” they squealed critically...

Five days have now passed.

“This Saturday is a good time to bring the children to the nearest field to build the Carbonaia and combine physical exercise with some useful recreation,” he jots down on the “Daily Register” where he records his daily class activities and all the individual grades. “When the Inspector from Parenzo reads about this, he will appreciate my initiative.”

The work proceeds rapidly in the early morning The older children clear an area of dry dead grass. The carbonaia is built in several layers of wooden bundles that are accurately placed to form a compact stack (catasta) shaped like a paraboloid.

The younger children are tired. They already yawn as the older ones work on the internal chimney which will be filled with lighter combustible material. The six and seven-year-olds help gather the dry tinder and the pine sticks full of resin. They all sit in the same classroom in front of the higher grades and now hope to ingratiate the older boys, thus avoiding future skull-numbing “scappellotti” during recreation.

The stack of wood (catasta) was covered the next day with more wood bundles. Quite a few parents showed up after church and helped the older boys to cover the carbonaia with a layer of clay and polverino (charcoal dust) about 6 inches thick.

The charcoal dust had been made in their open-pit carbonization process which they still practice in their back yards. They could still remember their grandfathers using the “carbonaia” method which was a nomadic process as they moved from site to site in the forests still available, but not far from secondary roads or trails. Water nearby was essential to douse the embers...

When they run out of clay they complete the overlay with grassy clumps of soil dug up from the few shady spots nearby. “Let’s provide some venting holes," my father suggests as an afterthought. “They will help the fire progress gradually from top to bottom!”

The carbonaia is finished and lit. An old man sits near some junipers and sips wine too tired to go home He will stare at the thin trail of smoke rising from the strange but yet so familiar shape, dreaming of thick woods and his trips to the seacoast.

Four days later...\

The time has come to strip the clay overlay in the evening. There is no time to reinstall the overlay strips to complete the carbonization gradually.

After the cooling off period, there is not enough water to douse the remaining embers rolling down the pile in red rivulets. The top of the chimney collapses inward; vulcano-like it spits up a cloud of fire-flies.

The old man limps back to his dreams and heads towards a deep sea of ancient memories stirred by the acrid smoke in the summer night.

My father takes me by the hand and walks away slowly from the carbonaia still smoking in the night - a little Aetna like the one that saw him born.

The Carbonaia is no more, but its smouldering embers still brighten my heart.


For the common istrian "carbonaia" the average output (within a very wide range) in the 1940"s was called the "STERO" equal to 65-75 kg of charcoal, For a two level carbonaia, (usually 2.5 -2.8 m high) the ouput was approximated by:

  • Output in 100 kg units = 3 C H, where C=circumference, H= height

For round sticks in the fascine ( bundle of sticks) the coefficient C may be as low as 2.5. Under favorable conditions the maximum output is 20% in weight (i.e. 20kg of charcoal per 100 kg of wood).

Length of carbonization process (not including erection and dismantling) under favorable metheorologic conditions (no rain) which could slow down the carbonization process, varied as follows:

No. of Days Output
2-3 7-8 stari (approx. 525 kg)
4-5 30-40 stari (approx. 2400 kg)
10-15 100-150 stari (approx. (8750 kg)

The shape of a carbonaia approximates a paraboloid (fat pine cone):

  • Volume V= P h/ 8 pi, where P= perimeter, h= height, pi= 3.1415

But reduce result by 4-6 %.

Photo source: La foresta di Leme e la Draga, Itinerari storico-naturalistici a piedi e in mountain-bike sulla direttrice Orsera-Antignana, Italo Svevo (Trieste, 1999)

The above photo is of a typical Istrian "carbonaia" almost complete and ready to receive the final cover of clay and/or sod. No side vents and center chimney are evident or visible in the photo. The paraboloid shape is the classic low aspect (height/diameter ratio) used in the early 1930's for small output "carbonaie" built in the Istrian woods to produce charcoal.

See also:

Related Links:

  • Typical Carbonaia construction in Europe (Photos) - (Source: Le fasi della carbonaia-Photos by Andrea del Zozzo): The carbonaia under construction (la carbonaia in costruzione) at - go down the page and click on "La coltura del bosco," then choose "Le fasi della carbonaia."

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This page compliments of Franco G. Aitala and Marisa Ciceran

Created: Sunday, August 15, 1999; Last updated: Saturday, May 07, 2016
Copyright © 1998, USA