Chaga: what it is

Chaga is the common name for Inonotus obliquus, a fungus that grows on birch trees in cold northern forests. What is harvested is not a mushroom with a cap and stem but a hard, black, deeply cracked mass that erupts through the bark, looking like burnt charcoal from the outside and rust orange to golden brown inside. That mass is a sterile conk: the fungus's dense growth, not its spore-producing fruiting body, which forms separately and rarely. Chaga is sold in the UK as a food supplement in chunks, powder, extract and capsules.

This guide covers what chaga is, where it grows, how it is harvested and prepared, and how to read a chaga label. It does not cover health claims, because no health claim for any mushroom is authorised in Great Britain.

Where it grows

Chaga is a parasite of birch. It grows slowly on living trees over many years, in Russia, Scandinavia, the Baltic states, Canada, the northern United States and parts of northern Britain. Most commercial chaga is wild harvested from Siberia, northern Europe or Canada, because it is slow to grow and hard to cultivate in a way that matches the wild material. The orange colour of the interior comes from compounds the fungus takes up from the birch, which is one reason chaga grown on anything else is considered a different product.

Wild versus cultivated

This is a chaga-specific point. Almost all chaga on the market is wild harvested, cut from living birch with an axe or saw. Cultivated chaga, grown as mycelium on grain or in liquid, exists but is a different material: it lacks the birch-derived compounds and the dense conk structure. A label should say "wild harvested" or "cultivated", and the region. Because chaga is slow growing and the demand has risen, sustainable harvesting (leaving part of the conk to regrow, not taking from young trees) is something careful brands mention.

How it is prepared

Fresh chaga is wet, heavy and hard. It is dried, then broken into chunks, ground into a coarse grind or milled into a fine powder. The traditional preparation across Russia and Scandinavia is a tea: chunks or coarse grind simmered gently in water for anywhere from 20 minutes to several hours, giving a dark brown liquid with a mild flavour. The same chunks are often re-simmered several times.

For supplements, the dried conk is extracted with hot water, alcohol or both, the liquid dried and the solids milled into an extract powder, which is then capsuled or sold loose. As with other mushrooms, whole powder and extract are different things at the same milligram figure; the label guide explains why.

The formats

Chunks

Dried pieces of the conk, sold by weight, for simmering into tea. The least processed format and the slowest to use. Not currently on our shelf.

Powder

Dried chaga milled fine, or an extract powder. Stirred into hot water, coffee or cacao. Chaga powder is brown and tastes mild and earthy with a faint vanilla note, less bitter than reishi.

Capsules

Extract or powder in a capsule with a daily count on the pack. No taste, no simmering. The chaga capsules we stock are 500 mg of extract, 90 to a pot, up to three a day.

Blends

Chaga appears in multi-mushroom capsules and in some mushroom coffees. In our six mushroom complex it is one sixth of each capsule.

Why chaga is dear by weight

Chaga takes years to form a conk large enough to harvest, only grows on birch, and is collected by hand in cold, remote forests. Once dried, a conk loses most of its weight as water, so a kilogram of dry chaga represents a good deal of fresh material and labour. That is why chaga chunks and powders cost more per gram than cultivated mushrooms such as lion's mane or shiitake, and why most brands sell it as a concentrated extract rather than as loose chunks. It also means the price of a chaga product tells you little about its quality on its own; the source, part and extract details matter more.

Storing chaga

Dried chunks and powder keep for a long time in a sealed container away from light and damp. Chunks that have been simmered can be dried on a rack and reused once or twice; brewed tea keeps for a few days in the fridge.

What it tastes like

Milder than most people expect. Chaga tea is earthy with a slight natural sweetness and a vanilla-like note, often compared to a weak, smooth coffee without the bitterness. It takes milk and honey well. In a capsule you taste nothing.

Reading a chaga label

• Source. Wild harvested or cultivated, and the region.
• Part. Sterile conk (the usual) or mycelium.
• Powder or extract, and the ratio.
• Beta-glucan percentage. If standardised.
• Milligrams per capsule, capsules per pot, daily rate. From these you get days per pot and cost per day.
• Capsule shell and other ingredients.

One more note: chaga is naturally high in oxalates, as are rhubarb and spinach. Brands do not usually print that, but it is a fact about the material.

Chaga at Herbastore

We list chaga on the mushroom supplements shelf, in capsule form and as part of the six mushroom complex, and every capsule we stock is under capsules. Each listing shows the amount per serving and cost per serving where the brand gives us the figures.

If you take any medication, have kidney stones or any medical condition, speak to a pharmacist or your GP before adding a supplement. This guide describes the fungus; it is not advice.