If you don't know how to make lye for soap, here it is.
Practice making some, as well as some soap, to become familiar with the process.
Here are some good recipes for cold and hot soap making as well as other old timey recipes.
Lye and HERE
- Start a rain barrel to catch soft water. This is a key step. Depending upon how much lye you want to leach, make sure that you have 2 or 3 gallons of soft water before you proceed.Water from a dehumidifier works as well.You can also use electrically distilled water. The purer the water, the more potassium that can be leached from the ashes. Do not use bottled spring water or water from the tap! (You can use bottled distilled water that was processed using steam distillation.)Get a wooden barrel and a cork about 3in (7.6cm) long. A cask-sized or waist-high barrel will work. You can find these at a local brewer's supply house.
- Drill a hole in the barrel approximately 2in (5cm) above the bottom. Make sure that the cork will fit snugly into the hole.
- Put the barrel on a brick base someplace where it will be undisturbed. Lye is caustic; take the necessary precautions. Put some bricks down and place the barrel on top of them. The brick base must be stable. It raises the barrel up so that you can easily drain off the lye into a container when it is ready. Give yourself room to work.
- Cover the bottom of the barrel with some palm-sized clean rocks (e.g. river rock). Cover the rocks with approximately 6in (15cm) of straw (this can be hay or grass). This will filter the ashes and help your lye drain cleanly.
- Gather branches and/or logs of oak, ash, or fruitwoods. Remember that the best lye is made from hardwoods, so avoid pine, fir, and other evergreens. Palm leaves work well if they are completely dried and brown.
- Burn the branches to ash. You can do this outside in a pile or, better yet, in a freshly-emptied fireplace or woodstove where the ashes won’t become mixed with anything else.
- Scoop the ashes out and put them in the prepped barrel. (Make sure that the ash is completely cold, or you could set your barrel and anything around it on fire.) You can fill the barrel with ash, but it is not necessary; you can make smaller amounts with less ash.
- Soak the ashes. Put a pan under the hole and remove the cork. Pour the soft water in until you see it start to drain into the pan, then put the cork back in tightly. After a day, the first ash should settle and you can add more ash.
- Let the ash soak for at least three days. If you want to use more ash, you can add it all week and drain it regularly (ex. on a specific day of the week).
- Check to see if your lye is ready. For what purpose are you leaching this lye? Body soap or heavy cleaning? Lye concentration gets stronger with each leaching. For average soap making, measure the concentration by dropping a fist-sized potato or a raw egg into the barrel (making sure to throw either of these away afterwards). If it floats enough for a quarter-sized area to rise above the water, it is ready. If it doesn't, you need to add more ashes or drain all the water and re-leach it (pour it back into the cask and let it set for one more cycle).
- When it's ready, catch your lye a wooden crock or glass container. Put it under the tap, gently pull the cork, and fill your containers. Leave enough head room so that they will be safe and easy to pour. Make sure that you have tight, fitting lids.
- Store your lye in a cool dark place until use. The sooner you use it, the better.