The festival's "Bring Your Own Picnic" policy explicitly allows outside alcohol for anyone 21+, and glass bottles aren't on the prohibited-items list — though the Concert Meadow's foot traffic makes a case for bringing something shatter-resistant anyway.

The Stern Grove Festival's official policy is clear: outside alcohol is permitted for anyone 21 and older, and glass bottles are not on the prohibited-items list. The festival runs under a "Bring Your Own Picnic" (BYOP) framework — the festival FAQ states, "Feel free to bring your own snacks and, if you're 21+, your favorite adult beverages" — and the official "What Can I Bring" page (sterngrove.org/what-can-i-bring) lists no restrictions on glass containers. Prohibited items include tarps, barbecues, knives over four inches, drones, and tall chairs.

One real caveat: security retains the right to restrict any item deemed a safety risk, even unlisted ones, per the festival's getting-here page. That clause exists; a standing ban on glass does not.

Practical tip: the Concert Meadow is a wall-to-wall blanket situation with constant foot traffic. A wine tumbler or soft-sided bottle is easier on you and your neighbors than a 750ml glass bottle. Not against the rules — just against physics.

Stern Grove Festival runs Sundays at Sigmund Stern Grove, 19th Avenue and Sloat Boulevard, San Francisco. Admission is free; shows start at 2 p.m. Full schedule at sterngrove.org.