Do loose roasted peanuts need a hechsher?

Answer: Yes.

Reason: Roasted peanuts are processed, so they must have a kosher certification, even when sold loose in the shell at a fruit store.

Source:

• cRc: unflavored raw nuts need no hashgachah; nuts that are roasted (dry roasted or oil roasted), cooked or flavored require a reliable hashgachah.

Related questions:

• Do raw nuts need a hechsher? No, if raw and unflavored (cRc).
• Do plain popcorn kernels need a hechsher? No.

More from Rabbi Tahan: Q&A: Hechsher on Peanuts

References: cRc (askcrc.org), “Peanuts”