Oregon winter white truffle

What it is

Tuber oregonense is an underground fungus that forms truffles, fruit bodies that grow below the soil. Its common name is the Oregon winter white truffle. Oregon State University Extension groups it with Tuber gibbosum under the name Oregon white truffles, and it is one of several native Oregon truffle species.

The catalogue calls it an aromatic culinary truffle. The species is recorded as wild in supply, and the sources reviewed do not state a current accepted name beyond the one used here.

Habitat and season

The Oregon State extension bulletin describes it as favouring young to early-mature Douglas-fir stands, especially those planted on former pasture land. It occurs from sea level to about 600 metres (2,000 feet) in the western Cascades and the coastal ranges, from Northern California to southern British Columbia.

Harvest is recorded from October through February, usually in the rainy season. The fruit body is a mycorrhizal partner of the trees and grows near Douglas-firs.

How to recognise it

Immature specimens are white to beige and firm inside, with little aroma. Mature specimens have a reddish-brown exterior with fissures and a smoky brown interior marbled with white. The aroma is described as garlic, spice and cheese, and it often develops one to three days after harvest. A mature truffle is about the size of a marble to a golf ball.

Spongy, squishy, hollow or powdery truffles are not edible. The extension bulletin notes that many truffle species are not gourmet edibles.

Use

Truffles of this kind are not cooked. Cooks shave them thinly over warm fatty foods such as eggs, meat, butter or a cream sauce, so the aroma reaches the diner. Harvested truffles are kept refrigerated in an airtight container lined with paper towels, and the extension bulletin says they last about a week.

Cautions

The Oregon State extension bulletin says, "Never eat a wild truffle or mushroom unless you have identified it with absolute confidence." It states that none of the native Oregon truffle species is poisonous, and that only four are considered gourmet edibles. This page is not an identification guide, and identification should rest on an expert.