Classic Bells > Soapy stuff > Tips for cutting soap

Tips for cutting a loaf of soap into bars

How to know when soap is ready to be cut into bars?

Some soap is ready to cut into bars at 6 hours and some soap is not ready to cut until 2 or 3 days go by. Until you have the experience to know how long to wait before cutting soap, you have to check the soap from time to time and cut when the soap has the right feel.

Soap is ready to take out of the mold and cut into bars when it feels like refrigerator-cold mild or medium-sharp cheddar, Gouda, or colby cheese. In other words, the soap should be soft enough to yield slightly when you gently press it with a finger tip, but firm enough that it doesn't actually dent.

Soap maker Zing shared this tip -- If your soap is in a silicone mold or silicone-lined mold, when "'s time to unmold, the sides easily pull away from the soap. If it's hard to pull away, then ... let it sit longer." (1)

Soap that is quite soft and easy to dent, like warm cream cheese, brie, or Havarti cheese, is too soft to remove from the mold without damage, so give it more time in the mold to firm up. When the soap becomes a bit firmer, but still dents with a finger press, you may be able to carefully remove the soap from the mold. Leave it on the counter to dry awhile longer until the soap is firm enough to cut cleanly.

Soap that is very hard and does not yield to a gentle press of the finger, similar to Parmesan or aged cheddar cheese, is probably too hard and brittle to cut well. Obviously you can take it out of the mold without any problems, but you might need to warm it in the oven and use a baker's dough cutter rather than a knife to get a clean cut (see below.)


How to prevent soap from shattering or cracking apart when it is cut?

Soap that is hard and brittle will be prone to cracking apart or even shattering into pieces as it is cut. But even soap that is at an ideal firmness sometimes cracks, especially at the end of the cut (see photo below for an example.)

To minimize the chance of cracking, avoid using a knife to cut soap. A knife has a triangular cross section, and the triangular shape can wedge the soap apart so the soap cracks rather than cuts cleanly. Instead, use a flat blade (a baker's dough cutter is popular) or a wire cutter (a cheese slicer or a wire soap cutter).

If the soap is so hard you cannot cut it with a flat blade or wire, preheat your oven to its lowest temperature setting, put the soap on a heat proof sheet, and set the soap in the oven to warm. Check the soap every 10 to 15 minutes and remove promptly from the oven when the soap softens enough so it can be cut successfully. It may be best to use a flat blade to cut the soap. A wire cutter is likely to break if the soap is still quite firm.

cracking from cutting with a knife
Soap bar that cracked during cutting. A knife was used to cut the bar



(1) Zing. When to de-box and cut? Soap Making Forum.