Castile soap – a well-known olive oil soap with a long-time
history, it is named for the city it reportedly originated. Originally made
from unfiltered olive oil and lye produced from burning the plant barilla,
castile soap still has an all-natural reputation and is perfect for vegetarians
and vegans as it is made of vegetable oils only. While in Spain castile soap means soap made in the
Castilla area from 100% olive oil, in modern times the term ‘castile’ can
have other meanings. Commercially available Castile soaps are often a blend of
olive oil with coconut and palm oils, and here castile indicates the bulk of the
oils comes from olives. The term castile is also used to indicate vegetable
oils-only soaps, and even slightly viscous liquid soap made only with vegetable
oil.
Aleppo soap at
the Al-Jebeili factory, Aleppo,
Syria (Creative
Commons)
Most people are familiar with the solid bar olive oil soap
and some might even know its Spanish roots. But did you know that another soap
made from only olive oil, called simply ‘white soap,’ originated in Northern
Italy hundreds of years before castile soap appeared in Spain? And the European claim is
not even as old as the even older more fabled source – Aleppo soap, made of olive and laurel berry
oils. This hard soap originated in the city of Aleppo and goes back at least a
thousand years; as well as its cousin Nabulsi soap, made in Nablus, Palestine.
It is generally thought that the invading ‘Moors’ of North Africa brought the
technology of making hard white soap with them to medieval Southern Europe.
With the prevalence of the plant barilla in Southern Europe - an essential
ingredient in the making of hard soap - the craft of hard soap making was
quickly picked up by the Europeans and evolved into lucrative local soap making
centers, like in Castilla, Spain and in Marseilles, France.
Why go through the trouble of making your own soap?
Not all soaps are made alike and unless you know what went
in it many olive oil soaps might not be as healthy as you would wish. There are
different grades of olive oil, depending on how it is processed. They all work
for making soap, though I would advice to stay away from pomace olive oil.
While this is cheapest, there is a reason! Pomace means that it
is made of the solid remains of the olive including skins,
pulp, seeds, and stems, and the amount of oil left is so minimal that it cannot
be extracted by pressing, but only through the combined use of chemical
solvents and extremely high heat. Cheap filler oils like canola and palm
oil are also often included in modern castile soaps. In the case of palm oil:
unless it is certified organic and sustainably farmed, I do not use it as
standard production attributes to rainforest deforestation. Olive oil-only
soaps are readily available from artisanal soap makers but sometimes it’s
easier – and a lot more fun – to just go ahead and make your own!
Why make soap in a soda bottle?
The exothermic or heat creating reaction of dissolving lye
crystals into water heats the water to (near) boiling and creates a lot of very
dangerous caustic steam. Experienced soap makers learn how to work around this,
either by making lye outdoors (and being upwind ourselves), by using
(partially) frozen liquid, or by using ventilation. The soda bottle method keeps
the steam contained as we wait for it to cool down and condense again. Steam,
as it is a water vapor, or gas, takes up more room than liquid water, and in a
confined area like a bottle will build up pressure. Soda bottles are designed
to take this pressure, as long as there is enough space left in the bottle to
do so. Using this technique anyone can make small amounts of hard soap without
the need for specialized equipment. But do always keep your wits about, as lye will
always be a potentially dangerous chemical.
Measuring out the
lye, the soap bottle and the water are at the ready.
Measured the oil.
Needed:
- 2 liter soda pop bottle, with lid.
- 5 gallon bucket
- Lye
- Water
- Ice cubes
- Olive oil
- Funnels (one for water, one for lye)
- Rubber spatula
- Scale, preferably digital.
- Paper Towels
- Household vinegar
- Rubber gloves
- Safety glasses
About the bottle:
PET (polyethylene terephthalate) bottles are not specifically
made for extreme temperatures; they are made to withstand pressure very well,
and are easy to get as 2 liter soda pop bottles. PET plastic should not contain
BPA but might contain traces due to the (recycled) manufacturing process. BPA
is not food safe but only releases slowly from contaminated plastic under high
temperatures, and while the lye creates high temperatures, it does so only for
a short while. To minimize heat, a
bucket with ice water should be at the ready before mixing the lye water.
Do NOT OVERFILL the bottle. Stick to the recommended minimal
amount of oil and lye. The empty space in the bottle is needed as a pressure
chamber for heat expansion. The exothermic (heat creating) reaction of
dissolving lye in water, heats the water to boiling and creates lots of steam.
This steam is highly caustic and VERY dangerous, hence the closed-off bottle
pressure chamber.
About the lye:
Up until recently, lye would be available in the household cleaning
isle of the supermarket and hardware store. Alas, as it is used to make certain
other stuff, this is no more. Do not buy liquid lye to make soap, as it is not
possible to measure the amount of dissolved lye correctly, plus, there are
additives added you do not want in your soap. Food grade lye can be bought over
the internet and I get mine from here: http://essentialdepot.com/
About Safety:
When working with
sodium hydroxide lye ALWAYS wear SAFETY GLASSES. It is recommended to wear
gloves, and always have household vinegar nearby for the unexpected splash or
droplet. Wear closed shoes and long sleeves if possible.
For a nice amount of hard soap for personal use a 10 ounce
olive oil batch works well.
Step by step:
- Measure 10 weight ounces of (room temperature) olive oil.
- Measure 1.26 ounces of lye.
- Measure 2 ounces of cold water.
- Fill a 5 gallon bucket with a water and ice mixture.
- Add water to soda bottle with funnel.
- Slowly but steadily add lye crystals to water in bottle
with the other dry funnel.
- When done, close lid immediately, and shake gently.
- Stick into ice-water right away when all the lye is
dissolved.
- The bottle will start to fill with steam, get scorching
hot and swell. Do not touch at the bottom! It should already be in the
ice-water.
- After about 5-10 minutes check bottle.
- If the bottle’s bottom shrank, it could benefit from
ice-water a little quicker next time.
- The steam should be condensing on the sides and run down
in droplets.
Water droplets
condensing on the sides.
A slightly overheated shrunken soap bottle bottom.
- When the bottom of the bottle, with the liquid, feels not
cold nor warm (body temperature, also called blood warm) it is time.
- Open bottle cap, and add oil to blood warm lye.
Oil sitting on
top of lye water.
All mixed up by shaking.
- And now it’s time to shake your booty! Do put the cap back
on first.
- Shake, shake, and shake some more…
- When the soap starts to stick and coat the sides of the
bottle like custard, it is good.
Raw soap at the ‘custard’
stage.
If you like, this is the moment you can pour the soap into a
mold, or into a small water bottle to make soap rounds (for instance to make
felted soap). Remove the top of the bottle first, and use a rubber spatula to
get it all out.
If you do not intend to mold, remove the lid, set it
somewhere safe and let it sit open until the sides of the soap are totally
firm. Cut off the top of the bottle, and pop out your block of soap!
Cut your soap to size in a week or so (do not wait too long,
olive soap is notorious for getting crumbly) Let the pieces dry on a cookie
drying rack in a cool and dark place for a minimum of three weeks.
Tip: you can let the soap dry completely in the bottle, but
make sure to remove the lid. If dried in a (partially) closed environment the
soap can ‘sweat’ a little – this will either go away on its own, or you can dab
it dry later with a paper towel.
As with all hand made soap, when in use place the soap on a
draining soap dish to let dry in between uses and it will go a long way - a
green Scotchbrite pad cut in half makes a fabulous cheap soap dish. As has been
said: the longer it sits, the harder it gets, and the longer it stays!
References:
Dunn, Kevin. Caveman
Chemistry. Universal Publishers, 2003.
Dunn, Kevin. Scientific
Soapmaking. Farmville, VA: Clavicula Press, 2010 (p.58)
About the safety of using plastic bottles:
About castile soap in general:
Creative Commons image;
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