We were with the Messenger of Allah ﷺ gathering kabath berries when he said, "Take the black ones, for they are the sweetest."We said, "Did you used to herd sheep, Messenger of Allah?"He replied, "Yes, and was there ever a prophet who did not?"
حدثنا عثمان بن عمر حدثنا يونس عن الزهري عن أبي سلمة
كنا مع رسول الله ﷺ نجتني الكباث فقال عليكم بالأسود منه فإنه أطيبه قال قلنا وكنت ترعى الغنم يا رسول الله قال نعم وهل من نبي إلا قد رعاها
Its isnad is sahih, and it is found in the works of the leading scholars. Bukhari narrated it in Fath [Bari] 4/441, no. 2264, in "Hiring," chapter "Grazing sheep," and Muslim in 3/1621, no. 2050, through the route of Yunus from him with the same wording, in "Drinks," chapter "The virtue of the black kabath." Ibn Majah also narrated it, no. 2149, and Malik, no. 971.As for al-kabath, it has been said to be the ripe fruit of the arak tree, and it has also been said to be a type of truffle. I consider it more likely to be a type of truffle, and indeed its good variety is the black one. As for the arak, I think the same applies to it.