Birch sap

Harvest

Birch sap is collected only at the break of winter and spring when the sap moves intensively.

Birch sap collection is done by drilling a hole into the tree trunk and leading the sap into a container via some conduit (a tube or simply a thin twig); the sap will flow along it because of the surface tension. The wound is then plugged to minimise infection.{{cite web|url=https://scholarworks.alaska.edu/bitstream/handle/11122/3198/Some%20impacts%20to%20paper%20birch%20trees%20tapped%20for%20sap%20harvesting%20in%20Alaska.pdf?sequence=1|id=R10-S&PF-FHP-2009-3

Birch sap has to be collected in early spring before any green leaves have appeared, as in late spring it becomes bitter. The collection period is only about a month per year.

No published evidence exists to quantify the long-term impacts of sap harvest on birch tree and birch forest health, or birch timber quality. However, the wounds caused by tapping birches consistently lead to dark staining in the wood. In one study, infection and wood decay had spread from more than half of old tapping holes.

In comparison to maples, birch trees are considered far less tolerant to the wounds caused by tapping, so more conservative harvesting practises have been recommended by trade bodies such as the Alaska Birch Syrupmakers Association.

Traditional regions

In Slavic regions the word "sap" is translated as "juice", i.e., "birch sap" is birch juice in Belarus (, Byarozavik), Bulgaria (Bulgarian: брезов сок, romanized: brezov sok), Poland (), Russia (), Slovakia (), Ukraine ().

Estonia (), Finland (), Latvia (), Lithuania (), Norway, Sweden ().

France, Scotland and elsewhere in Northern Europe as well as parts of northern China and both Hokkaido and Aomori as parts of northern Japan.

It is also widely used among the Pennsylvania Dutch, both as a traditional beverage in its own right, and particularly as a key ingredient in birch beer.

Composition

Birch sap contains heterosides (betuloside and monotropitoside), 17 amino acids including glutamic acid, as well as minerals, enzymes, proteins, betulinic acid and betulin, antioxidants, sugar (fructose, glucose and small amounts of sucrose) and vitamins (C and B(group)).

Nutritional and medicinal uses

Folk uses have been documented which include medicinal use, supplementary nutrition, and cosmetic applications for skin and hair.

Commercial birch sap and derivative products

Birch sap may be consumed both fresh and naturally fermented. Fresh birch sap is highly perishable; even if refrigerated, it is stable for only 7 days. Shelf life can be prolonged by freezing or preservation techniques. Existing preservation techniques include:

• Nothing i.e. bottled fresh sap (shelf life: 2–5 days refrigerated)
• Filtered with a 0.22-μ net (shelf life: 3 weeks refrigerated)
• Collected under anaerobic conditions (shelf life: 1 year ambient)
• Added sugar (3 g per 100 ml)
• Heat pasteurized, pasteurization should be conducted under specific temperature levels and times (shelf life: 1 year ambient). Although level of Vitamin C is lower than in fresh sap, all other benefits are preserved.
• Frozen at −25 °C (shelf life: 2 years)

Birch sap can also be used as an ingredient in food or drink recipes, such as birch beer or wintergreen-flavored candy.

Concentrated birch sap is used to make birch syrup, a very expensive type of syrup mainly made from paper birch in Alaska and Canada, and from several species in Latvia, Russia, Belarus, and Ukraine.

References

References

1. Svanberg, Ingvar. (2012). "Uses of tree saps in northern and eastern parts of Europe". Acta Soc Bot Pol.
2. Planter og tradisjon: Floraen i levende tale og tradisjon i Norge, Ove Arbo Høeg, Universitetsforlaget, 1974, {{ISBN. 8200089304.
3. Övre Dalarnes bondekultur 3, Lars Levander, Lund, 1947.
4. "Pennsylvania Birch Beer Recipe".
5. Kūka, Māra. (2013). "Determination of Bioactive Compounds and Mineral Substances in Latvian Birch and Maple Saps". Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.
6. (1935). "Un glucoside nouveau de Betula Alba L. Le bétuloside et son aglycone, le bétuligénol". Paris Masson ed.
7. (1989). "Identification and seasonal variation of amino acids in birch sap used for syrup production". Food Chemistry.
8. "Bouleau à papier (BOP)".
9. (2007). "Les Stratégies en Thérapeutique Antivirale".
10. (10 March 2014). "Cure de sève de bouleau et ses bienfaits multiples".
11. (2004). "Essential oil of Betula pendula Roth. Buds". Evidence-Based Complementary and Alternative Medicine.
12. Nicole & Olivier Lhomme, NICOLL-Nature, Le Bio Logis, [http://www.lebiologis.fr/medias/files/seve-de-bouleau.pdf La sève de bouleau]
13. (18 March 2023). "EASY BIRCH SYRUP RECIPES AND USES".
14. Alaska Birch syrupmakers association [https://www.fda.gov/ohrms/dockets/dockets/05p0295/05p-0295-cp00001-01-vol1.pdf Petition to US Food and Drug Administration for establishment of Standard of Identity for birch syrup, including the Alaska Birch Syrupmakers' Association Best Practices]{{dead link. (May 2025)