Birch sap
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Birch sap or birch water is the sap directly tapped from birch trees, Betula alba (white birch), Betula pendula (silver birch), Betula lenta, Betula papyrifera, and Betula fontinalis.
Birch sap may be consumed both fresh and naturally fermented. When fresh, it is a clear and uncoloured liquid, often slightly sweet with a slightly silky texture. After two to three days, the sap starts fermenting and the taste becomes more acidic.
Birch sap is a traditional beverage in boreal and hemiboreal regions of the northern hemisphere[1] as well as parts of northern China.
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 its 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.
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. Tapping a tree does not harm the health of the tree.[2] If the tap hole is not well plugged with a round tight fitting dowel there is a possibility that the sap continues to flow causing not only a loss of nutriment but also a risk of infection and fungal attack. This is best mitigated by the addition of pine tar (generally available at garden suppliers).
Traditional regions
Birch sap was a traditional beverage in Russia ([берёзовый сок / byeryozovyi sok] Error: {{Lang-xx}}: text has italic markup (help)), Latvia (Latvian: bērzu sula), Estonia (Estonian: kasemahl), Finland (Finnish: mahla), Lithuania (Lithuanian: Beržų Sula), Belarus ([Бярозавы сок / biarozavy sok] Error: {{Lang-xx}}: text has italic markup (help), Byarozavik), Poland (Template:Lang-pl), Ukraine (Template:Lang-uk), France, Scotland and elsewhere in Northern Europe[1] as well as parts of Northern China.
Composition
| Nutritional value per 100 g (3.5 oz) | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Energy | 4.6 kcal (19 kJ) | ||||||||||||||||||||
1.1 g | |||||||||||||||||||||
| Sugars | 1.1 g | ||||||||||||||||||||
| Dietary fiber | 0 g | ||||||||||||||||||||
less than 0.1 g | |||||||||||||||||||||
| |||||||||||||||||||||
| †Percentages estimated using US recommendations for adults,[4] except for potassium, which is estimated based on expert recommendation from the National Academies.[5] | |||||||||||||||||||||
Birch sap contains heterosides (betuloside and monotropitoside),[6] 17 amino acids including glutamic acid,[7] as well as minerals, enzymes, proteins, betulinic acid and betulin,[8][9][10] antioxidants,[11] sugar (xylitol, fructose and glucose) and vitamins (C and B(group)).[11]
Nutritional and medicinal uses
Folk uses
Folk uses vary from medicinal use, supplementary nutrition (minerals and vitamins) and cosmetic applications for skin and hair.[1]
| Region | Medicinal use | Cosmetic use |
|---|---|---|
| Belarus | lung diseases, gout | |
| Bulgaria | hair growth | |
| Czechia | poor health, infertility | against freckles |
| Estonia | (prevention of) eye diseases, skin diseases, source for vitamins | washing hair, against freckles and to bleach the skin |
| Hungary | stomach and lung diseases | against freckles |
| Latvia | “revitalization” | washing hair |
| Poland | “revitalization”, kidney stones | washing hair in order to strengthen it |
| Romania | kidney stones, jaundice, as milk-rennet, scab, diuretic | hair colouring, to remove sunspots and moles |
| Russia | externally against sores, to help children during teething | washing face |
| Sweden | scurvy, cholera | |
| Ukraine | treating skin diseases, source of vitamins, diuretic | against freckles |
| United Kingdom | tonic, rheumatism, first nourishment for new-born children | prevention of baldness |
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 up to 2–5 days. Shelf life can be prolonged by freezing or preservation techniques. Existing preservation techniques:[12]
- Nothing i.e. bottled fresh sap (shelf life: 2–5 days refrigerated)
- Filtered with a 0,22μ net (shelf life: 3 weeks refrigerated)
- Collected under anaerobic conditions (shelf life: 1 year ambient)
- Added sugar (3g per 100ml)[1]
- Heat pasteurized; pasteurization should be conducted under specific temperature levels and time spans (shelf life: 1 year ambient). Although level of Vitamin C is lower than fresh saps', all other benefits are preserved.
- Frozen at -25C (shelflife: 2 years)
Birch sap can also be used as an ingredient in food or drinks, 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[13] and Canada, and from several species in Russia, Belarus and Ukraine.
References
- ^ a b c d Svanberg, Ingvar; et al. (2012). Uses of tree saps in northern and eastern parts of Europe. doi:10.5586/asbp.2012.036.
{{cite book}}:|journal=ignored (help) - ^ http://www.tapmytrees.com/faq.html#q4
- ^ Kūka, Māra (2013). Determination of Bioactive Compounds and Mineral Substances in Latvian Birch and Maple Saps. doi:10.2478/prolas-2013-0069.
{{cite book}}:|journal=ignored (help) - ^ United States Food and Drug Administration (2024). "Daily Value on the Nutrition and Supplement Facts Labels". FDA. Archived from the original on 2024-03-27. Retrieved 2024-03-28.
- ^ National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington, DC: National Academies Press (US). ISBN 978-0-309-48834-1. PMID 30844154. Archived from the original on 2024-05-09. Retrieved 2024-06-21.
- ^ Sosa, A (1935). "Un glucoside nouveau de Betula Alba L. Le bétuloside et son aglycone, le bétuligénol". Paris Masson Ed.
- ^ Ahtonen, S; Kallio, H (1989). "Identification and seasonal variation of amino acids in birch sap used for syrup production". Food Chemistry. 33 (2): 125–132. doi:10.1016/0308-8146(89)90115-5.
- ^ http://www2.publicationsduquebec.gouv.qc.ca/essences/arbre.php?id=98
- ^ Bouchet, Jérome (2007). "Les Stratégies en Thérapeutique Antivirale": 24.
{{cite journal}}: Cite journal requires|journal=(help) - ^ http://www.santenatureinnovation.com/la-seve-de-bouleau-est-deja-la/
- ^ a b Demirci, B; Demirci, F; Hüsnü Can Baser, K; Franz, G (2004). "Essential oil of Betula pendula Roth. Buds". Evid. Based Complement. 1 (3): 301–303. doi:10.1093/ecam/neh041. PMC 538512. PMID 15841263.
- ^ Nicole & Olivier Lhomme, NICOLL-Nature, Le Bio Logis, La sève de bouleau
- ^ Alaska Birch syrupmakers association Petition to US Food and Drug Administration for establishment of Standard of Identity for birch syrup, including the Alaska Birch Syrupmakers' Association Best Practices. July 18, 2005.
