Why do candy bars have a zig zaggy pattern on the bottom?

[Tuxie]

Look at the underside of many candy bars (Snickers, Twix, etc). They have this distinctive zig-zag pattern on the bottom. What is its purpose?

[AncientHumanoid]

Conveyor belt marks? Just a WAG

[aceplace57]

Why do chocolate bars have a wavy pattern on the bottom?

Any chocolate with a pattern like that on the bottom of the piece has been placed on a patterned, plasticized fabric belt when the chocolate was wet and run through a cooling tunnel. Most likely, if you’re seeing the pattern on a mass-produced piece, the centers were run through an enrober, a machine with a fluid chocolate “curtain” that covers things with chocolate.

[Mijin]

That just leaves the “why” they use that kind of fabric belt.
I would guess that it’s important that the product doesn’t slide about, and that the gaps between adjacent products are maintained.

[kopek]

@Mijin

That just leaves the “why” they use that kind of fabric belt.
I would guess that it’s important that the product doesn’t slide about, and that the gaps between adjacent products are maintained.

And I would guess speed compared to the smoother/finer belts used for “fine chocolates”.

[oft_wears_hats]

Everyone else has already hit the nail on the head with this one. I would just like to add that I’ve used the absence of such a pattern as a method of verifying that chocolates were hand made. While visiting Brussels, we ended up needing to buy decent Belgian chocolates with very little time. We were in Grand Place, which is rather overpriced and touristy. I wanted to be reasonably certain that we were getting handmade chocolates, so I checked one of the clear plastic bags and noticed that the bottoms of each chocolate were smooth.

I’m sure some fancier chocolate factories might have smooth conveyor belts (Godiva, perhaps?), but AFAIK a handmade chocolate will also have a slightly concave bottom due to the meniscus formed by the chocolate against the mold.