Can I use other liquids in my soap? Can I use milk, beer, wine, coffee, purees or any other liquid in my soap making?
The short answer is yes yes yes.
The long answer is, yes but you need to be aware of a few things first.
Lets just start with water, it is a relatively benign substance, does not contain fats or sugars and therefore does not bring any particular complications to your soap making. In fact your only consideration really is whether to use tap or distilled water. That in itself is a pretty hot topic and one for another day but I use tap water and we live in a hard water area. Never had a problem and I flatly refuse to buy bottled water and contribute even more to our plastic pollution problem. I know there will people out there who will be horrified at that statement but it is a decision I have made for a good reason and I am comfortable with it.
Aside from water, there is very little liquid that you cannot use, however you need to have an understanding of the properties of that particular liquid so you can account for it in your soap making process.
Lets take milk as an example. You can use any kind of milk, plant, animal or even human if that takes your fancy!
Milk is largely made up of water, fats, protein and carbohydrates. The % of fat it contains will add to the moisturising properties of your soap but it is not classed as one of your butters or oils - it is used entirely as a water replacement - in full or in part (and this goes for all liquid alternatives including purees)
As you will know, when you add your sodium hydroxide to your room temperature liquid and stir the temperature of that solution increases rapidly to around 200F. That is hot.
As our milk contains sugars, if we allow that to happen it will scorch and go brown as well as not smell too great, so we have to compensate for that. We freeze our milk and add the lye to the frozen cubes slowly to ensure that the temperatures stays low, ideally below 100f. You will end up with something that resembles thick wall paper paste in the end but that is normal and it will blend in to your butters and oils with no issues. After blending to trace, avoid allowing your soap to overheat. You could even put it the fridge particularly if you live in a hot climate.
Above - coconut milk soap pebbles coloured with cocoa powder and activated charcoal.
What about fruit and vegetable purees?
In the interests of transparency I would like to say I have never tried to use fruit or vegetable purees but the process would be the same as for milk. They are high in sugars - some more than others - and will scorch when mixed with the sodium hydroxide if that is how you choose to add them.
You have some choices in how to use them, You can either blend, strain and use as all or part of your water. In this scenario freeze them as you would milk and then add your lye slowly.
Alternatively if you were only wishing to use a small amount you could blend and add at trace. If I were using the second method I would be considering a water discount to compensate for the extra water in the puree. A bit of trial and error will be required but somewhere between 10 & 20% would be a good start depending on the quantity you are using. Bear in mind too that the fruit or vegetable may affect the colour of your soap. Pureed carrots or pumpkin is a good example of this. As for milk soaps, do not allow it to overheat once it is in the mould.
Let's look at coffee ( and teas) in your soap making.
I love the smell of coffee, can't bear the taste which is a shame but it can be used in soap. As can any brewed tea. Unfortunately the saponification process is harsh and the smell cannot usually be detected in the finished bar. It makes for a unique product however and a great gift for coffee ( or tea) lovers.
Your tea or coffee can be used with no major issues as a direct substitute for water, just make sure it is cold before you try and use it. You will also need to bear in mind that the colour of your soap will reflect the liquid. In most cases it will turn a brown colour to one degree or another. On a side note, you can also add coffee grounds to your coffee soap. Just keep the used grounds to one side and add a spoonful or so to your soap after trace, it does make for a scrubby, exfoliating bar so bear that in mind when deciding how much to add.
Finally alcohol, beers, wines and spirits!
Yes , this is a real thing and again would make a great gift for the beer or wine lover in your life. It comes with it's challenges of course as you would imagine.
Firstly alcohol is generally high in sugar which takes us back to the milk and puree scenario - it will scorch. In addition it contains alcohol, which states the obvious I know, and also may be bubbly (carbonated) all of which are not idea when mixed with sodium hydroxide but there are ways around it.
Carbonated liquids are a definite no no ( unless you want to see an interesting caustic volcano) but this is easy to resolve just by leaving the lid off for a while.
Alcohol is it's standard form is also a no no - think volcanoes again. The exception to this may be a weak beer for example, but you will still need to ensure it is flat.
All other alcohol will need to be prepped by boiling off the alcohol before using it, and then allowing it to cool before freezing it. For this reason I would advise against using spirits as that is an awful lot of alcohol to boil off. The liquid will still be high in sugars so we need to treat it as we would for milk or purees. This may seem a lot of faffing around but it does create a unique product and it is worth noting that the sugars in the alcohol will boost the lathering properties of your soap. As for milk and puree soaps, remember not to allow it to overheat once in the mould.
That is a bit of a whistle stop tour of using alternative liquids in soap making. There is more I could have included in here and I did think about making each one a full blog in it's own right but having all the information in a relatively simple format initially seemed to be the best option.
Using alternative liquids does not have to stifle your creativity either, you may just need to think outside the box a little to accommodate the colour changes that your chosen water replacement creates.