Breaking the glass is the one part everyone knows. Here's what it means.

It's the moment your guests are waiting for, including the ones who've never been to a Jewish wedding, because they've seen it in a film. It's also the moment most likely to go slightly wrong, and the one couples spend the least time planning.

Why is a glass broken at a Jewish wedding?

At the end of the ceremony one or both partners step on a glass wrapped in cloth, it shatters, and everyone shouts "Mazel tov!" The oldest explanation is that it recalls the destruction of the Temple in Jerusalem, so that even at the happiest moment there's a deliberate note of grief. Over time couples have layered other readings on top: that the world is broken and a marriage is a promise to repair some of it, or that some things can't be undone, so choose carefully.

What does it mean now?

Whatever the couple says it means, which is unusual for a ritual this old. Most officiants offer a sentence or two of interpretation before it happens, and there's no single approved reading. Common ones, all in wide use:

• A memory of loss held inside a moment of joy, so the celebration isn't naive.
• A reminder that the world needs repair and this household will do some of it.
• Everyone who couldn't be here — the grief in the room made audible.
• The irreversibility of the commitment, since the glass can't be put back.

Pick one and tell your officiant. A ceremony where the glass is explained lands differently than one where a man stomps on something and a room shouts.

Who breaks it?

Traditionally the groom. Today, very often both partners together, or each breaking their own glass, or one partner if the other is in shoes that make it a bad idea. Same-sex couples generally break one each or step on one together. Nobody will object, and the version where both people do it reads better to a mixed crowd anyway.

If it's one glass and two people, practice the choreography once at the rehearsal. It's small and it's the last image of your ceremony.

What glass do we actually use?

Not a wine glass, and this is where things go wrong. Use something thin and easily shattered, wrapped tightly in a cloth napkin or a purpose-made pouch. A lightbulb is the widely used practical answer — it breaks with a satisfying sound under almost any shoe, and the glass is thin enough that there's no risk of an ankle turning on an unbroken stem.

Practical rules learned the hard way. Wrap it completely, in fabric that won't let a shard out. Never use lead crystal, which is thick and can survive a stomp. Have someone assigned to remove the wrapped bundle immediately, especially at an outdoor or barefoot-friendly venue. And if the person breaking it is in soft shoes, check they can actually do it before the moment arrives.

Kits sold for this run $15 to $60 and often include a keepsake vessel to hold the fragments afterward. A lightbulb and a cloth napkin cost nothing and work just as well.

Can we keep the pieces?

Yes, and lots of couples do. Glass artists make the fragments into a mezuzah (the small case fixed to a doorpost of a Jewish home), a bowl, a paperweight, or a piece of jewelry, usually $80 to $400 depending on the piece. If you want this, say so before the wedding and give someone the specific job of collecting the bundle. The alternative is a venue employee sweeping it into a bin at 11pm, which is the usual outcome.

Do we break a glass at an interfaith wedding?

Very commonly, yes. It asks nothing of either partner theologically — there's no blessing to say and no declaration to make. It's a gesture, it's the most recognizable Jewish wedding moment to non-Jewish guests, and it gives a ceremony an unmistakable ending.

It's also the easiest place to bring both families in. A sentence from your officiant that names what the glass is for, including anyone the couple has lost from either side, turns the loudest moment of the ceremony into the most inclusive one.

What do guests shout?

"Mazel tov!" — literally "good fortune," used the way "congratulations" is. If a good portion of your guests won't know that, have your officiant say so about thirty seconds before: "when the glass breaks, the traditional response is to shout mazel tov, so please do."

Say it plainly and everyone joins in. Leave it out and half the room claps tentatively while the other half yells, which is a small deflating end to an otherwise good ceremony.