Thousands of years ago before soap was available, people made their lye the old-fashioned way by leaching water through wood ashes layered in a barrel or other container. If you’re in a far corner of the globe and can’t get lye locally, or are just curious how it’s made, you can make potassium hardwood lye yourself. However, you will need specific supplies and will have to follow several steps using safety equipment. One way to produce lye in your home kitchen is with rainwater and hardwood ash, which you will have to collect. You need a wooden barrel, metal containers for the ashes, a rain barrel to collect the water, and safe containers to capture the leached lye water. The process involves boiling the ashes from a hardwood fire (soft woods have too much resin to mix with fat) in a little soft water—rainwater is best. Boil for about half an hour, let the ashes settle to the bottom of the pan, and then skim the liquid lye off the top. A drill is necessary to make the holes in the barrel, and you will also need small pebbles and straw. Tools for testing pH, such as strips or a meter, are helpful when testing the lye. After the fire has gone out, let the ashes cool for a few days before collecting them. You will need enough ash to almost fill the wooden barrel. Store the white ashes in metal containers. Place the rain barrel under the eves of your house to catch as much water as possible. You will need to have a filter on the top of the barrel to keep out any debris and leaves. Collect about 10 pints/4.7 liters to make the lye. Once the holes are drilled, place a 1- to 2 -inch layer of small clean pebbles on the bottom of the barrel; just be sure the stones are bigger than the holes. Then add about 3 inches of straw on top of the pebbles. This acts as a filter, allowing the water—and not the ashes—to drain out. In order to place the bucket that collects the liquid below the barrel, you will need to first raise the barrel up. To do this, prop the barrel on sturdy blocks or a wooden frame that is high enough to fit the bucket underneath. Position a lye-safe bucket so it lines up with the holes you drilled in the bottom of the barrel. Stainless steel and heavy-duty plastics are often lye-safe, but aluminum is not. Slowly pour the collected rainwater over the ash so that the ash is wet but not soaking. It is easiest to fill buckets with the rainwater first, and then pour each bucket into the wooden barrel. Once the ashes begin to float and you can see the waterline, stop filling the barrel. Note how many buckets of rainwater you add so you know how much lye water will be produced. You will need enough lye-safe buckets to match the amount of water you add to the barrel. You do not need to place a lid on top of the barrel unless it has been placed in an unprotected, open area. It is time to collect the lye water when it is within 4 inches of the top of the bucket. Carefully remove the full bucket, being sure not to spill, and replace that bucket with another lye-safe bucket. The pH of each bucket of lye water needs to be 13 or more. If it is below 13, carefully pour the bucket of lye water back into the wooden barrel and collect it again. Repeat this process until your buckets of lye water are at a pH of 13. It will most likely take at least one more run through the barrel to reach the right pH level. Take care not to splash when pouring the liquid back into the barrel as the water can burn your skin.
