What is Lye?

Lye is a strong alkali that is used in soap making, among other things. It is also known as caustic soda or sodium hydroxide (or historically potassium hydroxide).

Lye Ingredients

The ingredients for making lye are wood ash and water. Preferably rain water, as it is soft, although tap water will work just as well. The ash should come from hardwoods as soft woods are too resinous to mix with fat. Ash and Beech give good results.

The Traditional Method of Making Lye uses Wooden Box or Barrel

Take an old wine barrel or stout open wood box and make sure that it is clean. Elevate it so that you can then place an iron bowl, bucket or similar underneath the leaching hole at the bottom of your barrel/box to collect the lye water when it is ready to emerge. Place a bung in any existing opening in the wine barrel, and drill a smaller hole into the barrel/box that is only 1/8th inch wide. What you are aiming for is a hole wide enough for the water to drip through but small enough for the ashes not to fall out. Keep this hole closed up with a small bung until later.

Now pack the bottom of the barrel with clean river stones. If using a box a layer of charcoal will do. This works as a filtration system. After the filter place a generous layer of straw on top. Your straw should take up at least half way up the barrel/box.

Shovel in your ashes until the barrel/box is as full as you want it. You can add a thin layer of straw to keep the ash in. After that, pour over some hot rain water in small amounts so that the whole contents are wet and soaking but not flooding. Using hot water is important as the hot water will draw out more potash from the wood ash than cold water, making your lye stronger.

Traditionally, a little lime was mixed with the ashes to 2 – 5% which then guaranteed that you would have good lye for soap making.

On day 2 you can add more ash and water after allowing the ash from the previous day to settle.

• If your ashes start floating to the top then you know that you have added too much water.
• Make sure that what you are placing in the bucket is the fine, white ash, as opposed to any charcoal bits.  These you don’t need.
• To make your lye potash more like caustic soda you can sprinkle a little quick lime onto your ashes before pouring on the hot water. (Not easy to get in small quantities these days, and treat with caution as it needs to be handled with extreme care.)

On day 3, make sure your receptacle is ready under the opening on the barrel/box, remove the bung and wait for the lye water to slowly trickle out. Don’t expect to have a bucketful. You will only be getting a small amount as this should give you the right strength needed to make good natural soap.

At this stage you need to get it to an even strength to use for your soap making. Boil this liquid again until you are able to do the “float test” and get it to work. See instructions below.

This is the traditional way to make lye. Winchester’s have a suitable box which you can use to demonstrate the process. It needs to be set up in a tilted position and draining into a suitable receptacle.

If you make lye this way, take care at this stage as the lye is caustic and if it splashes onto your skin and into your eyes it will burn. You will need to wear gloves (and safety glasses if out of the public eye) at this point.

Once you have enough lye water boil it carefully and then pour it back into the bucket/box for a second go. This will strengthen the lye.

How to Test the Strength of your Lye

To make lye and be successful at soap making your lye has to be at the right strength. Now there are 2 ways in which this can be done, both of which indirectly involve chickens.

Test 1

This is a simple test. Take a chicken feather and place it in the lye. If the feather dissolves, the lye is strong enough and you can use it for your soap. If not, you will have to re-boil the lye water when it emerges and repeat the process until your chicken feathers dissolve.