Introduction: Make Your Own Lye

Picture of Make Your Own Lye

Lye is incredibly easy to make! It's just the product of combining water with hardwood ashes, and it's essential for making your own soap.

Step 1: Gather Materials

Picture of Gather Materials

Materials are pretty minimal. You'll need:

5 gallon (or any large) bucket

smaller bucket to fit inside the larger one. We used a clay one, but you could use any material that you can drill holes through.

Metal mesh- But do not use aluminum! Lye will eat through aluminum


piece of soaker hose

Hardwood ashes

zip ties

Step 2: Determine Where to Drill Your Holes

Picture of Determine Where to Drill Your Holes

We used a clay pot because the material is easy to drill clean holes through, and it already had a large hole in the center. Flip the pot upside down, and determine where to drill your holes. It doesn't have to be exact, you just need several holes throughout the bottom of the container.

Step 3: Drill the Holes

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Step 4: Place the Mesh

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Take a sheet of the metal mesh, and fit it to the bottom of your smaller container. We did this by just placing the mesh over the bottom of the pot and cutting around it. Cut several sheets of mesh because you will layer them. When you've cut about 3-4 sheets of mesh, flip your pot right-side up and layer the mesh at the bottom. We used glue to secure the mesh in place, but you don't have to; the ashes should secure it to the bottom adequately.

Step 5: Make a Soaker Hose Coil

Picture of Make a Soaker Hose Coil

Take a piece of soaker hose (aka gardening hose), and wind it into a circular coil that's roughly the diameter of the clay pot top. We evenly spaced and secured our coil by zip tying small wooden blocks throughout it. Your finished coil should look like the third picture here, the idea of the coil is just to make sure water is distributed over all the ashes.

Step 6: Place Your Smaller Clay Pot Into Your Larger Bucket

Picture of Place Your Smaller Clay Pot Into Your Larger Bucket

Step 7: Fill With Ashes and Soak With Water

Picture of Fill With Ashes and Soak With Water

Fill the clay pot with hardwood ashes (cedar, oak, etc.) Then, place your coil of soaker hose on top. Attach your soaker hose to a garden hose, and turn the water on. That's it! The mixture of water and hardwood ash creates lye. The water will filter through the ashes and the holes in the clay pot, and the finished lye will collect in your bottom bucket. Depending on how much lye you want at once, cut the water off after about 5 minutes. You can take the lye out of the bottom bucket on an as-needed basis and re-use this system again and again. The ph of lye should be about 14, and you can test the ph of your finished lye water with ph strips sold in the aquarium department of walmart.

Step 8:


Swansong (author)2017-10-13

I didn't realize the setup was that simple, that's pretty neat! I'd like to learn how to make my own soaps, it looks like fun :)

Lorddrake (author)2017-06-09

what happens if you use soft wood ashes?

phantom_white (author)2015-09-15

This is a really easy method of making your own lye. I'll have to try it sometime. I enjoy making homemade soaps (love the customize-ability of it!) in the crock pot. It's cheap and a fun afternoon project. I've seen a lot of comments saying you can get lye for $2.50/lb- can't imagine where they're finding it. I paid $11 for a 2lb container and that was the absolute cheapest I could find without getting it shipped to me and paying RIDICULOUS shipping and hazmat charges. This method may save me some money, but does someone know the conversion rates from crystallized lye to lye water?

Dunno if it's still true, but when I was younger, you could find lye in the same aisle as Drano at the grocery store. Granted, this was when dinosaurs roamed the earth, but some places may still have it.

GavinF2 (author)femmepasseule2016-08-21

Lye, Sodium Hydroxide, Caustic Soda, these names are that of a single product which is available in your supermarket cleaning aisle.

But isn't it more fun to tell that smug hippie soap maker at the fair that their soap is not completely handmade like yours is because they didn't make their own lye.

static (author)GavinF22017-04-24

LOL wouldn't telling to hippie that in itself be smug? Black pot meer black kettle.

ggadget (author)GavinF22016-08-22

Excellent point. Lol.

stevenn20 (author)femmepasseule2017-02-06

Still Available at places like Smart & Final for about $ 3.00 per 16 oz container. I think it goes by the name Red Devil

static (author)2017-04-24

In regards to SHTF preps I may as well stockpile lye. very few harwodd tree growing in the Jigh Plains to burn

BronsonMMiller (author)2017-01-13

Well I just wanted to thank you. You're instructable was most informative! I've been meaning to look into how to make lye for a while now for when the SHTF and I just stumbled across it while looking for something else here! Also the best comment section I've seen on Instructables haha

Sawhitt (author)2016-08-21

Sorry, but this is an awfully complex way to do something as simple as making lye. It's expensive, too, when compared with the traditional ways we used/use on the farm.

JohnC430 (author)Sawhitt2016-08-21

well why dont you enlighten us with your method instead of hurting the guys feelings?

Sawhitt (author)JohnC4302016-08-21

It's simple. Fill a bucket or barrel with wood ashes, preferably oak. Tap a hole at or near the bottom. Slowly pour water through the ashes, catching the "son-to-be" lye as it runs out the hole. You can either filter with a cloth or screen as it exits the first container or when you pour it into a kettle to further reduce the filtrate into true lye over heat (You're removing excess water by heating.
Bonus: After you've cooked the filtrate down, re-filter if necessary to remove foreing particles, add lard, glycerin. mineral oil, or vegetable oil - add herbs or fragrances if desired, cook it down to a thick consistency, pour it out to flatten and harden as it coos, the cut. Soap!

BronsonMMiller (author)Sawhitt2017-01-13

That's the exact same thing, only with more steps and less details.... Awfully complex you say? ......... MMMmmmmmmmkay.

dsmith84 (author)2015-08-15

Thank you for sharing this instructable. This seems like a very effective way to get lye from ashes. But using wood ash produces potassium hydroxide lye which you can absolutely use to make soap, but in my experience it makes a lousy soap. Sodium hydroxide is way better and super cheap from either a soap supply store, or I get mine from the hardware store as a pure NaOH lye drain cleaner for 3 bucks a pound.

Other than soap and cleaning are there other uses for lye? Am I alone thinking that KOH isn't as good as NaOH?

Great job!

LeNeveu2 (author)dsmith842016-08-22

I use this method to tan my deer and squirrel hides.

Kwolf12 (author)LeNeveu22016-09-23

Nifty, LeNeveu2. Could you go into a short bit of detail on how you do that and where the wood-ash lye comes into it? I produce a lot of acorn flour, so I end up with huge amounts of tannin and a boiled concentrate does a great deal of the treatment on my hides. But I'm curious about other ways people tan their hides.

savegrace (author)Kwolf122016-11-27
For instance...

CraigH23 (author)dsmith842016-08-24

I accidentally made NaOH while making hydrogen gas by electrolysis of water. It was going very slowly so I figured common salt (NaCl) would help conduction and speed things up. It did speed my hydrogen production up, but on smelling the strong smell of chlorine gas at the other electrode, and some school chemistry I realised that the remaining solution must be NaOH, caustic soda

terrynight (author)dsmith842015-08-16

You are correct: potassium hydroxide makes a lousy hard bar (if at all), but is better suited for LIQUID soap! There is an instructable for making liquid soap in a crockpot somewhere on Instructables - try it! It yields quite a substantial amount of soap :-)

eddand (author)terrynight2016-08-21

I have a bar of soap I made with my grandmother in the 1950's It was my job that year to collect the hardwood, it was mostly black cottonwood, burn it collect the ash and wash it. we made 'hard' soap bars that were used mainly to take stains from clothing before washing them. except for one time she caught me swearing.

terrynight (author)eddand2016-08-22

Nnnnoooooo!!! Hahahahahaaha!

DIY-Guy (author)eddand2016-08-21

Then grandma used that soap on the foul-orifice, right?

teddlesruss (author)dsmith842016-08-21

Wood ash lye was used to process olives, which makes sense, they had the wood, used cooking fires, and therefore had plenty of ash. I'd do this as a self sufficiency exercise, not just for olives but also because lye can be used as a sterilising wash that also happens to dissolve lipids, i.e. not bad for cleaning down a processing area. Also, try getting hold of NaOH in sufficient quantities for cleaning, processing, and soap making without getting suspicious sideways glances from the supermarket staff... %)

GavinF2 (author)dsmith842016-08-21

This can also be used to produce hydrogen for fuel when mixed with aluminium or it can clean your drains. There are man y great uses for Caustic Soda.

The Green Gentleman (author)2016-08-22

I like this setup for leaching salts from wood ash. The soaker hose is a great variation. However, this is not producing any kind of lye. It is producing potassium carbonate, whereas the lye used in soap making is either potassium or sodium hydroxide. You would need to boil this with calcium hydroxide to turn this into lye. Leaching salts from wood ash is an important step toward making lye, but not the only one:

What was called wood ash lye certainly was and is made from wood ashes. It does not matter just what is in it exactly but it was used for millennia for making soap. I have no doubt that modern science is much better.<> describes making it and using it for making biodiesel and has a link to a book on making soap with it. My Grandmother and Grandfather (born in the 1880's) made their own wood ash lye, using a wooden hopper with straw in the bottom to filter the solution in a stone trough I presume my grandfather made, as he was a stone mason. For laundry my grandmother mixed lard and wood ash and boiled the clothes with this in a wash boiler and called it "soft soap" . While I use Wikipedia a lot, everything in it is not the only way things were done. A web search on making soap in Colonial days will give links to the fact that lye made from wood ash was used. It may well have a lot of carbonates in it. So, this is a valid process that was used in soap making. I can attest that a bunch of wood ashes and water will dissolve your skin. I have never done a chemical analysis on it, but it is a strong alkali.

T'aint lye. At least, not in the current sense. It's primarily carbonates, bicarbonates and a little sodium hydroxide and potassium hydroxide. You can definitely make soap from it. It's not as efficient as what we now call lye, which is almost pure potassium or (more commonly) sodium hydroxide. The link you provided is referenced in the Wikipedia article on Wood Ash. That link also states that the potassium hydroxide content of wood ash is often questionable. The ability to make soap from something does not make it potassium or sodium hydroxide. If you look at the comments, most commenters seem to think the "lye" referred to here is a hydroxide, because for the last hundred and some years, the term "lye" has meant either potassium or sodium hydroxide. I was praising this set up, but trying to clear-up some confusion among the commenters about the product created.

boatmakertoo (author)2016-08-22

Nice apparatus. Actually the solution produced is a mix of sodium and potassium hydroxide. It is used, as one correspondent says, to create hominy by soaking dried corn and rinsing away the shell. Hominy is eaten as is or dried and ground to make grits or ground further to make masa which is mixed with lard and made into tortillas. All of these products may be more easily from your supermarket.In our family lye soap was made with small amounts of vinegar to neutralize excess lye. Not an exact thing so one sometimes felt and smelt like a pickle after a bath. At least it did not remove the skin. Another use for wood ashes or the lye is in ceramic glazes. It provides the flux needed to reduce the melting point of other minerals. Another use is to mix the lye or the ashes with leguminous compost and urine to produce nitrates which can then be made into gunpowder. Wood ashes and lye were once commonly used to adjust the pH of soil in farming and also provide sodium and potassium for the crop.

Skunkworx (author)2016-08-22

I saw a few people ask what other uses might there be for Potassium Hydroxide (KOH). It is the electrolyte of choice for Nickel-Iron batteries. NiFe batteries are some fascinating old-school technology with some real-world applications and are definitely accessible to the DIY community.

GCPedersen (author)2016-08-22

People asked what else lye can be used for.

Making grits. Back in the old (old old) days, people took dried corn (and/or) field corn and soaked it in lye to make grits.

GavinF2 (author)2016-08-21

I wouldn't cut the blocks of wood this way either but, really, how many posters do we really need whinging about how Marcus does it?]

boffincentral (author)2015-08-12

That operation being demonstrated with the circular saw is extremely dangerous. For anyone reading this, please do not emulate this!

Do it the way that works for you!

The average mug has no idea how dangerous a circular saw is. That was all I was pointing out. Do it another way. Heck, use a hand saw. It isn't going to take that much longer and it will be a lot less time then the time wasted in the emergency section at your local hospital.

I've got ten fingers, and I intend to keep them!

GavinF2 (author)boffincentral2016-08-21

Do it the way that works for you!

namora (author)2016-08-21

I just bought a 2 lb jar of Red Devil lye at a fragrance and soap making supply store in Seattle for eight dollars. Perhaps online it could cost a bit less but I perfer to support local businesses.

GavinF2 (author)namora2016-08-21

Why would someone buy something so easy to make?

Have some pride in your work. If you are browsing this website you probably want to make things yourself so why buy something so easy to make. I bake food rather than buy processed because it is so easy and you can enjoy it with the pride of someone who has made their own.

Same rules apply.

mhays8 (author)2016-08-21

WoW, I'm an old man & never new how lye was made. Thanks a lot, now I know how to make Castile soap from total scratch!

twotower (author)2016-08-21

The day may come, when something as simple
as lye, may for whatever reason, no longer available. If that time ever
comes, having certain skills like lye making, could possibly determine
who survives and who does not.

It's sad to me that some of the commenters don't see the necessity of
familiarizing oneself with such a basic skill for making an incredibly
valuable product. I would like to know how many of these people even knew that lye is made from hardwood ash?

is an incredibly strong base that can be use for a myriad of household
and industrial applications i.e. as a food additive, a drain cleaner,
soap making, a chemical solvent and basification agent. Hardwood ash has
been used for thousands of years by indigenous peoples of the Earth to
remove the fur from a skinned animals in preparation for tanning. Golden
brown German pretzels get their amazing taste from being dipped in lye,
not backing soda before being placed in the oven! Backing soda will
work, but it's not as good as using lye solution. The list of uses for
lye go on and on.

Lastly, I find it a sign a sign of stupidity
for an individual to criticize or somehow lessen the value of the
information being shared. It doesn't mean you can't or shouldn't order
your lab grade NaOH off of the internet. If nothing else, at least one
has learned something new.

TwistedFrosty (author)twotower2016-08-21

"If you only do what you can do, you will never be more than you are now" ~Master Shifu

antagonizer (author)2015-08-13

Reading through the comments, I've seen you post nearly half a dozen about his lack of safety with that saw. Don't get me wrong, I totally get it...unnecessary danger and all that, but if the guy feels comfortable doing it, then let him take risks his own way. I wouldn't worry about anyone copying him, either, as there seems to be a consensus that he's a Darwin award at play so I'd say there's no real risk of that.

Glass blowers work with 2000 degree glass mere inches from their faces, and chemicals...don't get me started. Knife makers keep their hands even closer than that, to abrasive equipment that could wear a finger to the bone in seconds. No safety net, chum. Then there are welders, pipe fitters, those guys that work at the top of wind generators...

I take risks daily, and I have for 30 years. A few cuts
and burns, but as my grandfather used to say, "great people who do
great things make great sacrifices". I may not be great, but I'm working
on it and sometimes you need to put your fingers a little close to the blade in order to make something really awesome.

If you wager nothing, you need not look forward to anything.

thuzil (author)antagonizer2015-08-13

But why take an unnecessary risk? As many people have pointed out, there are several better ways to cut small blocks of wood.

I honestly couldn't care less if the author cut all of his fingers off improperly using a skill saw.

antagonizer (author)thuzil2015-08-14

I had a table saw break my nose about 15 years ago cutting thin strips from oak. Funny thing was, I was playing it safe. Blade guard down, using push sticks, safety glasses, zero clearance insert, but it still threw that piece up into my face. It was the blade guard that caught it. If I had done it the 'unsafe' way, I'd still have my pretty nose and now, and when I buy a new table, the guard is the first thing to come off.

Now, I'm not saying that unsafe is better, only that when you've done it for a long time, you tend to find your own level of comfort. It's like driving. Loud music, drinking coffee, arm out the window, chatting with passengers...all unnecessary risks, but after 30 years in the driver seat you learn to mitigate any potential for disaster that could come out of those activities. Sure they're still risks, but I think they invariable develop you into a better driver, just as risking fingers close to the blade can turn you into a better craftsman.

Well said

alihagan (author)2016-08-21

Love this. Been saving fat to make soap. Can't find anywhere to get lye in Hawaii. Im sure it's available somewhere but haven't found yet. I have all the materials so im going to give this a try.

Mugsy Knuckles (author)2015-08-18

Soap is cheap too. And honestly the soap you buy at he store almost certainly of higher quality than a backyard soapmaker will turn out.
But that's not the point.

JL McK (author)Mugsy Knuckles2016-08-21

the soap you buy in the store is full of toxic chemicals: Synthetic fragrances always have pesticide to keep you from being swarmed by bees. Solvents and volatizers are petroleum distillates. Antibacterials to prevent mold growth during vatting.

JohnC430 (author)JL McK2016-08-21

yeah right! with all your paranoid way of thinking about "pesticides" in soap. are u also a vegan?

JL McK (author)JohnC4302016-08-21

No. What difference does it make what I do or do not eat?

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