Stop Cutting Cake With a Knife. Here's a Way That's Faster and Cleaner

Cutting a cake can be tricky business. It's difficult to keep delicate piping intact, let alone make pieces that are proportionate. And good luck finding a big knife at a picnic or office party.

Fortunately, there's a surprisingly effective way to cut a cake while preserving its beauty: Use dental floss.

I know that sounds weird but it works surprisingly well. I tested different types of dental floss on three types of cake and the results were clean slices that would make any professional baker proud. 

It's also a lifesaver in a pinch, since most of us keep floss tucked away in a pocketbook, gym bag, office drawer or medicine cabinet. 

How to cut cake with dental floss

A strand of floss is thinner than the average kitchen knife and it's designed to slide easily through tight spaces without causing damage. (If you do it right, the frosting builds up on your fingers, not on the cake.)
First, make sure the cake is on a flat surface so you have room to pull the floss all the way to the bottom. (You could put it on a cake stand to give you more room as you slice down.)

Next, spool out a length of floss bigger than the widest part of the cake. I left several inches on each end to wrap the floss around my fingers comfortably. When you wrap the floss around your fingers, don't make it super tight: You're trying to cut a cake, not your fingers. 
If you're trying to make each slice the same size, you may want to use the floss to lightly mark guidelines before cutting.

Square or rectangular cake: If the cake is shaped like a square or rectangle, it may be easier to cut because those cakes are generally shorter than round cakes. Using your floss, make your cuts across the cake lengthwise, pressing firmly into the cake to cut all the way through. Now make your cuts widthwise, slicing to the bottom of the cake. 

Round cake: If your cake is shaped like a circle, it's possibly a layer cake so you may need to apply a bit more pressure to make it all the way to the bottom of the cake. Using your floss, firmly cut through the center of the cake to create two halves -- you may need to move the floss in a sawing motion to fully cut it. 

Then, make a cut that's perpendicular to the one you just made -- you should now have four even slices. Continue cutting across the cake until you have the right number of slices.
The thinner you want your slices, though, the harder it will be to cut because they'll begin to fall apart.

Pro tip

Once you've sliced to the bottom of the cake with your floss, don't pull it back up. That brings crumbs and frosting to the top of your cake, and you won't get the clean, tidy look you're after. (It also makes the floss messier and means you'll need to get a new strand for every cut.)

Instead, once you've sliced all the way through to the bottom, let go of one end and snake the floss out. Most of the icing and crumbs will wipe off the floss as you pull, leaving a clean strand you can use to cut the next slice. 

Which type of floss works best?

I tested two types of Oral-B floss, a waxed floss from Kroger and both unwaxed floss and waxed dental tape from CVS on three different cakes: A layer carrot cake, a tall sheet cake and a shorter, denser sheet cake.

All the floss worked great and made neat cuts, though the Oral-B Glide sliced through the cakes a bit easier.  (Despite worries that it would snag, the CVS brand unwaxed floss worked well.)

The only one that smeared a bit was Kroger's dental tape, which looks more like a ribbon than a thread. It still made a fairly clean slice, though, and I'd use it in a pinch. 

Flavored vs. unflavored floss?

I was worried using flavored floss would change the taste of the cake but we cut pieces of chocolate sheet cake using Oral-B mint-flavored floss and none of our four taste-testers detected any mintiness.
To be safe, stick with plain, unflavored floss if you can and steer away from cinnamon-, coconut- or bubblegum-flavored floss. 

Where the floss didn't hold up

When slicing the larger cakes, I noticed the floss sometimes didn't cut all the way to the bottom easily, maybe because of the increased resistance. 
I suggest cutting the cake in half first and then working with each half so there's less cake -- and resistance -- to get through. It might also help to put the cake on a stand to help you slice it all the way through.