Author(s): Stefan Tschirpke (external author)
Editorial office: WSL, Switzerland
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The production of birch sap in Finland

For centuries it has been known that birch sap is a health elixir. A family business in the east Finnish province of Tohmajärvi has been successfully producing birch sap for many years on a small industrial basis.

Fig. 1 - Arto and Susanna Maaranen produce birch sap.
Photo: Stefan Tschirpke
Fig. 2 - Russian birch sap
Photo: Precender, Wikipedia, Public Domain

Every spring Arto Maaranen wanders thoughtfully through his birch forest which contains magnificent healthy birch trees, with straight trunks, 40 to 60 years old. He and his wife Susanna own 7 hectares of birch forest in Tohmajärvi, a remote corner in Karelia near the Finnish- Russian border, about 500 km north east of Helsinki. Maaranen is looking for signs which show that the birch trees are coming to life.

He reaches for a twig and breaks it off. If it drips out of the break, he says, then it is a sure sign that "Mahla", the birch sap is flowing up from the roots into the branches. He alleges that when he puts his ear to the trunk he can even hear the birch sap flowing. According to an old Finnish wives tale the "Mahla" flows when the snow has melted leaving a clear circle around the foot of the birch tree.

Assumed medicinal benefits

About four weeks long, from around the beginning of April to the middle of May, the birch trees "pump" nourishment stored in the roots during the last summer up into the buds. This is the time when many farmers, or town people who own forests, tap their trees. The birch trees are usually "milked" for home consumption – this has been done for centuries because the sap is said to have many medicinal benefits.

Unfortunately, there has been very little research on this subject. According to Heikki Kallio, Professor for food chemistry at the University of Turku, the composition of birch sap is well known. The sap contains many minerals and trace elements in a diluted form, including calcium, magnesium, sodium, sugar and fructose. Kallio confirms that there are many first hand experiences and views on the positive medicinal benefits of birch sap. What is lacking up to present are systematic, clinical studies. Kallio is a protagonist for an in depth study of birch sap. A possible focal point, according to the food chemist, could be the effect of the sap on diabetes mellitus, on the urinary tract and kidneys as well as on general health.

Producing birch sap commercially?

Arto and Susanne Maaranen do not just tap the sap for home consumption. In the middle of the 1990’s the couple made a radical decision. Arto, who at the time was around 40 years old and working in marketing, and Susanne who was working as a translator, bought an old house and 7 ha of birch forest in Tohmajärvi and founded the company Oy Aurinkolehto LTD in order to develop the production of birch sap as a small scale industry. No one had ever tried this before.

They were considered ecology nuts affirms Susanna laughingly. Reports on the medicinal benefits of birch sap affirmed their idea that there must be a market for such a product. "There are many claims that birch sap drunk regularly helps reduce rheumatic joint problems and combats pollen allergies and headaches. There are also reports about the general rejuvenating effect of the sap and that it reduces hunger pangs caused by stress at work. From Professor Kallio we learnt that in the past farmers gave their cows birch sap in spring to build them up quickly after the long winter."

Cable clutter in the birch forest

Fig. 3 - The collection tubes which "cable up" the birch wood are used for the extraction of birch sap. The preservation of the sap is more of a problem than its collection.
Photo: Stefan Tschirpke

The birch forest starts just behind the spacious house in which not only the apartment but also the production and store rooms are situated. Around 700 trees are connected by thin tubes. In each birch tree a hole has been drilled at a height of around 2 m. The holes are two centimetres in diameter and depending on the thickness of the tree 5 to 8 cm deep. The birch sap runs out of the holes through tubes into the collection pipes and then on into the processing room to be bottled. During the season between 50 and 300 litres of sap per birch tree are collected. Arto assures us that the trees are not damaged as only a portion of its fluid nourishment is extracted. Old tap points will close naturally by tree growth.

After the sap is extracted it is glass clear. Straight away it is automatically filled into half litre bottles. This part of the production process however is not open to outsiders. Arto Maaranen: "we have fiddled around and experimented for around 10 years and invested a large amount of money, more than that I cannot say. It is a trade secret. Just this: it is a one hundred percent natural product. The bottled birch sap does not contain any additives whatsoever."

The preservation problem solved

The journey to achieving a product ready for selling was not a smooth one. The main difficulty was that the bottled birch sap could in the beginning only be kept in a fridge and not at room temperature. "We were often disappointed at the end of the tapping season when we realized: the sap goes off too quickly. It was still not a finished product." reports Susanna. Together with laboratories and food chemists and after many studies and tests, they finally managed to solve the preservation problem of the birch sap.

In spring 2001 the first bottle of sap went onto the market. Since then sales have flourished, but the Finnish market is too small. Up to 97% is exported. Not only do they export to central Europe they have now also entered the Japanese market. Susanne proudly reads the evaluation of the Japanese tasting council: "our birch sap tastes slightly sweet and contains the fine aroma of the tree." In Finland people are now also aware of the innovative and persevering entrepreneurs. In November 2002 the company Aurinkolehto was presented with the INNOFINLAND-Prize by President Tarja Halonen for the industrial production of birch sap and for solving the problem of preservation.

    Translation: Dawn Meister, Stallikon


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