Making of Eco soap by used oil

English Japanese

Mom said, “Used-Tempura-oil is filled up, so can you make soap by this?”

Sure! I will!! 😀


At first, I weigh the oil in a balance.
How heavy is it~?

The oil that used for fritter or tempura for 2 or 3 times, I measured it, the weight was exactly 500g.

From the weight, I calculate the other ingredient’s weight.
Water is 1/2 from the oil, it means 250g.
Caustic soda multiplied 0.14 by the oil is 70g.

But I make Eco soap, so I wanna more eco, I use washed-rice-water instead of normal water.
(*We Japanese normally, wash rice by water before cook.)

Washed-rice-water has a lot of vitamins and minerals, so it makes our skin beautiful XD

Well then, the ingredients are these.

Used oil 500g
Washed-rice-water 250g
Caustic soda 70g


Here are Washed-rice-water(left one) and Caustic soda(right one).


Put caustic soda to washed-rice-water, then mix.
Temperature will rise suddenly, so be careful!
I’m putting gloves on hands and mask on my mouth.


Well, the oil that I already weighed put on fire to around 50 degree.
(Normally, they put hot water under the oil though,,, I’m lazy that I skip it 😛
But it’s danger, so you’d be better not to do that like me.)


When the washed-rice-water and caustic soda mix’s degree decrease to around 50 degree, mix both liquid.


Mix, mix.

Mix, mix.

Mix…in 15 min, it makes me tired, so leave it and I mix it again every an hour.


At the same time, I spray those tools I used with vinegar.
The tools is alkaline state, so the vinegar make it neutralize.

Then I wash the tools by sponge just for this.

Check the pre-soap liquid every an hour, when you find a line on the liquid when you mix, (the softness is like a mayonnaise)


put it in a milk box, then put the box in a Styrofoam box.


Opened it in 24 hours, hummm, it seems soft a little bit, but it’s ok.


Break the milk box.


Cut the soap a piece by knife.


Put the soaps in line~.


Hey! I made these soaps by 500g used oil~! XD
The smell is like a tempura, smells yummy(LOL)

Then put the soaps on proper shady and airy place for 1 month to dry.


After a month.
Whoooo!! Such a black colored used oil a month ago re-born beautiful white soap~****

Usually, the soap made by used-oil is use for washing clothes or dishes though, it has a lot of minerals that it may be good for body too actually.

For body, I used washed-rice-water and took long time to make it!

Then,,, when I made bubble by net…
the bubble is soooo fine and silky~!!!

So I washed my face and body though, sooooooo gooood!!!
It buff my skin so much~!!

Then I put hand-made lotion on my face, then I went to bed.

Next morning,,,,what a beautiful my skin is~~~ XD

Whoa~, it’s a kind of waste if I use these soaps for clothes or dishes..

Well next, I will make rice bran soap~*

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