Birch trees (genus Betula) are widespread across the Northern Hemisphere, found throughout boreal and temperate forests. Several species — particularly silver birch (B. pendula) and paper birch (B. papyrifera) — have long been tapped for their sap, which flows freely in early spring before the leaves emerge.
Birch sap is a clear, slightly sweet liquid with a faintly woody flavour. It has been consumed as a traditional spring tonic across Scandinavia, Russia, the Baltic states, and by Indigenous peoples of North America for centuries. It can be drunk fresh, fermented into birch beer or wine, or reduced into a syrup (though it takes roughly 100 litres of sap to make one litre of syrup, compared to about 40:1 for maple).
Birch wood is also the traditional source of xylitol, a sugar alcohol widely used as a low-calorie sweetener, though most commercial xylitol is now produced from corn cobs.
How it's produced
Birch sap is harvested by drilling a small hole into the trunk in late winter or early spring, when rising temperatures cause sap pressure to build. A spout is inserted and the sap drips into a collection vessel. Each tree can yield 5–20 litres per season without significant harm. The tapping season is short — typically just 2–4 weeks — and the sap is highly perishable, requiring refrigeration or immediate processing.
Birch sap harvesting is predominantly a wild-harvest activity, as birch trees are abundant in boreal forests and rarely cultivated specifically for sap. For xylitol production, birch wood chips or bark undergo a multi-step chemical process involving acid hydrolysis to extract xylose (wood sugar), which is then hydrogenated into xylitol.
What it costs the planet (per kilo)
≈ Estimated from its category — typical for sugar, not measured for this item yet. Sources & methods →
What comes from this
Your household's take
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