The nibble and spit test is a traditional method used by experienced mushroom foragers to aid in identifying mushroom species in certain groups including the genera Russula and Lactarius, and some members of the Boletales order. This test involves chewing a small piece of the mushroom for a few seconds at the front of the mouth and then spitting it out without swallowing. It’s important to note that this test should only be performed after tentatively identifying the mushroom to these specific groups, as applying it indiscriminately can be dangerous.

Application in Specific Genera:

Russula: The test helps distinguish between edible species and those with acrid or peppery tastes, which are typically inedible or mildly toxic. 

Lactarius: Similar to Russula, the test can reveal a mild or acrid taste, aiding in identification.

Boletes: The test is often used to detect bitter or unpleasant tastes that indicate inedibility. However, caution is advised, especially with certain toxic species, such as those in the Rubroboletus genus, which can cause adverse reactions even without ingestion.

Important Precautions:

Accurate Identification: Ensure the mushroom belongs to Russula, Lactarius, or a non-toxic member of Boletales before performing the test. Misidentification can lead to exposure to harmful toxins.

Avoid Swallowing: Always spit out the mushroom material after tasting. Ingestion, even in small amounts, can be dangerous with certain species.

Allergic Reactions: Be aware that some individuals may have allergic reactions to specific mushrooms, even without ingestion.

The nibble and spit test can be a useful tool for experienced foragers in identifying certain mushrooms when applied correctly and cautiously. However, it should only be used as a supplementary method after thorough identification and with a solid understanding of local mushroom species and their potential risks.