A whiskey thief is a tool that master distillers use to extract small portions of whiskey from an aging barrel for sampling or quality control.[1] The old-fashioned ones are made typically of copper and resemble a drinking straw in design.[2] It has a coned narrow hole at the bottom and a vent hole at the top in which a distiller can cover with the thumb once the device is inserted in the barrel to trap and lift the whiskey out.[3] By removing the thumb from the upper vent hole, the whiskey is released to drain into drinking glasses for tasting.[3]
This same tool can be used for sampling other distilled spirits or wine from large vessels, hence it can also be used as a wine thief.[2] Newer models may be made of clear plastic or glass with the larger models having the capability of accepting a hydrometer for testing purposes.[4]