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Birch sap is collected only at the break of winter and spring when the sap moves intensively. When fresh, it is a clear and uncoloured liquid, very similar to water, 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 may be consumed both fresh and naturally fermented.
Birch sap contains heterosides (betuloside and monotropitoside), 17 amino acids among which glutamic acid, minerals, enzymes, proteins, betulinic acid and betulin, antioxidants, sugar (xylitol, fructose and glucose) and vitamins (C and B(group)).
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.
Birch sap was a traditional beverage in Russia (Russian: берёзовый сок / byeryozovyi sok), Latvia (Latvian: bērzu sula), Estonia (Estonian: kasemahl), Finland (Finnish: koivun mahla), Lithuania (Lithuanian: Beržų Sula), Belarus (Belarusian: Бярозавы сок / biarozavy sok, Byarozavik), Poland (Polish: Sok z Brzozy), Ukraine (Ukrainian: Березовий сік / berezovyi sik), France, Scotland and elsewhere in Northern Europe as well as parts of Northern China.
|Region||Medicinal use||Cosmetic use|
|Belarus||lung diseases, gout|
|Czech Republic||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|
|Poland||“revitialization”, 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|
|Ukraine||treating skin diseases, source of vitamins, diuretic||against freckles|
|England and Scotland||tonic, rheumatism, first nourishment for new-born children||prevention of baldness|
Nutritional and medicinal uses
Birch sap is commonly known for its detoxifying, diuretic, cleansing and purifying properties. Heterosides present in birch sap release methyl salicylate by enzymatic hydrolysis which is analgesic, antiinflammatory and diuretic. The activation of diuresis helps eliminating organic wastes such as uric acid and cholesterol. Birch sap is also known for helping with joint and bone health, loss of hair, arthritis, and weight loss.
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:
- 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)
- 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 sap’s, all benefits are preserved
- Frozen at -25C (shelflife: 2 years)
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