To Finns nothing spells out ’C L E A N’ more clearly than the natural pine wood smell of mäntysuopa, Finnish pine soap. It’s the smell of long, lazy childhood summers, saunas, lakes, boats – and rag rugs. It’s a time-travelling Proustian smell that can transport you back to childhood in a heartbeat. It’s a fresh pine wood scent very different from pine needle essential oils and pine fragrance oils which often smell like toilet cleaner.
Mäntysuopa is one of the most commonly known, used and trusted household products in Finland. It’s available in every supermarket and while other cleaning products come and go, mäntysuopa stays. We like mäntysuopa and if you ask the man in the street in Helsinki to mention a traditional Finnish soap he will mention mäntysuopa first. Many years ago when I moved to South Africa (long before my days of soapmaking) I made sure to pack a bar of mäntysuopa – just in case..
The history of mäntysuopa
For a traditional soap mäntysuopa is a fairly recent invention.
Large forests and plenty of water have always been the main natural resources of Finland. Saw mills were first established in the 1500s and the first pulp mills came in the early 1900s.
In a drive to utilize by-products of pulp manufacturing Alfons Hällström at Enso-Gutzeit in Kotka began experimenting with pine wood oil distillation in 1913. In 1920 the first mäntysuopa soap mill was established and the first bars of mäntysuopa hit the market.
Mäntysuopa is an un-superfatted pine soap made with pine wood oil and rosin. Both pine wood oil (aka tall oil from the Swedish word for pine oil, ’tallolja’) and rosin are by-products of the pulp manufacturing process. The fact that the soap lacks superfat makes it more suited for cleaning purposes than as a bath or skincare soap. Mäntysuopa has always been marketed and labelled as a cleaning product.
The main fatty acids of pine wood oil (not to be confused with essential pine needle oil) are oleic acid and linoleic acid. Rosin, aka colophony or Greek pitch (not to be confused with pine tar), is a solid pine oleoresin obtained by vaporizing the liquid terpene components from fresh pine resin. It’s main fatty acid is abietic acid.
Rosin has been used extensively in industrial soap manufacture. The amber colour of Pear’s Transparent Soap was originally from gum rosin. Tall oil is still the main ingredient in the American classic Murphy Oil Soap.
The ground-breaking new pine soap soon became popular and in the years following World War II the sales of mäntysuopa reached 4 million kilos a year in Finland. That’s an impressive amount of cleaning soap considering that the Finnish population was less than 4 million at the time.
Despite its name – mäntysuopa literally means ’pine soap paste’ – the original mäntysuopa was a bar soap saponified with sodium hydroxide. Perhaps the reason for the inaccurate name was a wish to make clear to customers that this soap was a cleaning soap rather than a bath soap. In those days ‘suopa’ i.e. soap paste saponified with potassium hydroxide was associated with cleaning and laundry.
In the 1960s liquid mäntysuopa was launched. The liquid version was intended for general cleaning while the bar version remained the intended laundry soap. These days the liquid version outsells the bar soap by far.
The initial popularity of mäntysuopa is easy to understand if you compare it with alternative soaps at the time. In the early 1900s imported goods and commodities were relatively expensive in Finland and imported soaping oils like coconut, palm kernel and olive would have been reserved for luxury toilet soaps. Cleaning and laundry soap was made with readily available animal fat, mainly tallow, high in stearic acid – and was often lye-heavy.
Laundry soap made of tallow works well – when used with very hot water. In cold water – and particularly in hard cold water – tallow soap does not perform particularly well since stearic acid soap isn’t very well soluble in cold water – compared e.g. to coconut soap. The oleic-linoleic mix in mäntysuopa worked reasonably well in cold water and the addition of abietic acid from the rosin further improved both cleansing and lather in cold water. In old mäntysuopa adverts this performance in cold water was often mentioned.
Why was washing laundry in cold water of interest in the days before modern washing machines? Well, Finland has over 100000 (yes, that is the correct number of zeros) freshwater lakes and 1250km of coast line. Lots of water in nature meant lots of places to wash laundry in cold water. And in Finland water in nature is very, very cold for the most part. So, a new soap that worked well in those conditions was a very welcome innovation indeed.
In the days when mäntysuopa was first introduced sustainability was generally not a high priority and the early pulp mills were no champions of environmental friendliness. But, as a natural, vegan, compostable product made from by-products of local industry and local natural resources mäntysuopa was in certain ways well ahead of its time.
These days, in Finland like everywhere else, synthetic detergents are readily available and widely used, but for certain purposes we still prefer mäntysuopa.
Finland has a long tradition of rag rug weaving. Wall-to-wall carpeting never became very popular in Finland and rag rugs woven from strips of recycled clothing, curtains, bed linen etc have been used for centuries and can still be found in most homes.
Rugs covering floors need washing every once in a while. In Finland that is done outdoors, in summer, with mäntysuopa. Scrubbing rag rugs with a hard brush in summer sunshine is something of a rite of passage for Finns from all echelons of society. And Finns will tell you that few things smell as nice as a clean house with clean rugs freshly washed with mäntysuopa.
If you visit the Finnish countryside in summer you’re likely to come across rag rug ’stations’: several high scrubbing tables with big wash basins. In the early days of mäntysuopa, rugs were scrubbed on jetties or smooth granite rocks right by the sea or a lake. Today rug washers know better and rug washing stations are always at a distance from the shore. As a natural soap mäntysuopa is easily bio-degradable and compostable, but the rosin acids are harmful to fish and care should be taken not to let mäntysuopa run straight into waterways.
For sauna cleaning mäntysuopa is also very popular. Sauna being a Finnish concept (the word ’sauna’ is Finnish and means ’bath house’) most households have one. Again the statistics are mindboggling: with a current population of 5 million, Finland has 3.2 million saunas. Finnish saunas have wooden floor decks, wooden seats and wooden wall panels and these get a regular scrubbing with mäntysuopa: Rinse with hot water to open the grain, scrub with a hard brush and mäntysuopa and rinse well with cold water to close the grain again.
The use of various essential oils in Finnish saunas is a modern concept: the only sauna smell considered acceptable by previous generations was the smell of mäntysuopa and birch twigs.
For many mäntysuopa is the go-to oven cleaner and generations of Finns have cleaned paint brushes with mäntysuopa. But apart from obvious cleaning uses, mäntysuopa is also used as a natural pesticide. A solution of mäntysuopa and water is sprayed on plants to combat aphids and soft-skinned insects both indoors and outdoors. Due to lack of scientific evidence of its effectiveness as a pesticide it can’t be marketed as such, but this use of mäntysuopa is nevertheless widespread and popular in Finland.
As times and ways change, new uses for mäntysuopa may well develop: mäntysuopa is apparently great for soaking Citadel paint off Warhammer miniatures..
Mäntysuopa in Cape Town
With this Finnish mäntysuopa soap heritage in my baggage, I’ve been toying with the idea of making my own pine soap for a long time. When you spend enough time away from home you can get nostalgic about surprising things..
So, when I recently managed to get hold of some tall oil fatty acids and some rosin here in Cape Town an experiment was urgently called for.
Tall oil comes in many different grades with different rosin concentration etc. Crude tall oil is about 50% fatty acids and 40% rosin acids whereas tall oil fatty acid (TOFA) is about 97% fatty acids and only about 1.5% rosin acids. In the early 1900s when mäntysuopa was first introduced it was probably made from crude tall oil rather than from tall oil fatty acids. I’m assuming that tall oil fatty acids are being used in commercial mäntysuopa today.
At any rate fatty acids was what I could get my hands on so fatty acids it was. The pine wood smell out of the bottle was definitely spot on. The rosin acid content could be increased by adding gum rosin.
Mäntysuopa experiment #1
True to chronology I first set out to make an un-superfatted bar soap with tall oil fatty acids, rosin and sodium hydroxide.
Saponification charts don’t often give saponification values for tall oil, tall oil fatty acids or rosin but I had the supplier’s saponification value for the tall oil fatty acids so that was a good start. The rosin was trickier. It didn’t come with a saponification value so I was left to my own devices – and Google.
Saponification values are averages so I eyeballed an average value on the rather wide fork of intervalls that the internet gave. Eyeballing lye amounts is not something I ordinarily do, but in this case I was experimenting with a cleaning product rather than a skincare product so I wasn’t too concerned.
Then came the challenge of how to incorporate the rosin. Rosin melts at about 75-85C so I decided to heat my tall oil and rosin in the crock pot and hotprocess the soap. I wasn’t sure if the rosin would solidify if I let the mixture cool down so I decided to keep the oils in my small experimental batch at about 60C – which is much warmer than I usually soap.
Seeing that the oils were very warm, I added a tiny amount of lye solution to see what would happen. It bubbled quite a bit, but more interestingly the few drops of lye solution seemed to saponify the surrounding soap immediately. So, I ended up adding the solution a spoonful at a time, stirring constantly. By the time I had incorporated all the solution the soap was gelling away merrily. A zap test a couple of minutes later gave nothing but soapy taste. In the mould it went and that was it.
So, now I had my own solid mäntysuopa smelling exactly right and slowly cooling down. You probably need to be a Finnish soapmaker to understand the full extent of my excitement – yeehaa!
Mäntysuopa experiment #2
Since I had more fatty acids and rosin I decided to make a potassium version too: an actual ‘suopa’ or soap paste.
Again I melted the rosin with the oil in the crock pot and let it cool down to about 60C. Again I added the lye solution (water and KOH, no glycerine) a tiny bit at a time and by the time I was done adding I had a thick paste. This time I used quite a bit more water and I had to cook the paste for several hours before it started getting translucent. Once it got to that stage a zap test came back flat, but even though I cooked it for several more hours it still didn’t become transparent.
Yet, a first test run of the fresh paste was very successful. I recently made two small rag rugs and now I gave them a good scrubbing with a little bit of tall oil soap paste and a hard brush. The paste lathered nicely and the rugs came out nice and clean with fabulous, authentic smell of unscented tall oil soap.
Despite my passion for bar soap I’ve never yet managed to work up much enthusiasm for liquid soap. Extra water and plastic bottles? Why bother? Well, now I had some nice soap paste for cleaning purposes. Why not turn it into something I could easily dilute and spray on the aphids on the lime tree in the garden?
With some kind and helpful pointers from South African soapmaking friends I managed to dilute the paste to liquid soap still with a nice bit of viscosity.
Since I’m a novice at liquid-soap making I’m not sure why the paste and subsequently the liquid soap didn’t turn transparent. It’s possible that my aim for an un-superfatted soap was off the mark and that the final product in fact contains unsaponified fatty acids. On the other hand I can’t see any signs of oil rising to the surface after more than a week in the bottle. It’s also possible that the lack of glycerol in this soap made with fatty acids rather than oil has something to do with it.
But, as I said before, my experimental liquid soap seems to be working well and I can live with the lack of clarity.
These bottles will now be tucked away for a few months. Right now we’re experiencing a severe drought in our region of South Africa and all potentially water-guzzling projects like rug washing need to be put on hold at least until April when the rainy season (hopefully) starts again. Once we get there I have a handsome line-up of rugs that will do well with some proper mäntysuopa treatment.
Pine soap experiment #3
As mentioned mäntysuopa made with tall oil and rosin is a cleaning product, not a bath soap. But I still had some tall oil fatty acids left and so I decided to see how they would work in a coldprocess soap for use on skin. This time I decided not to use rosin. Extra rosin would have improved lather but since I wanted to make this soap without heating the oils too much I skipped the rosin. By eliminating the rosin I was also hoping to limit the acceleration of trace.
So no rosin, but instead I added some coconut – both for lather and hardness. The first bar soap had been rather soft after 24h, with a distinct oleic acid sliminess. I was hoping that a bit of coconut would keep the slime in check. I also added a small amount of castor oil to sustain lather.
And so without rosin and with cooler oil I was expecting to make standard room temp coldprocess soap – which I normally do with water at 20% of oil weight.
I poured my room temp lye solution into my room temp oil and switched on the stickblender. Seconds later I had the hardest soap concrete I’ve ever seen in the dome of the blender. This wasn’t just some run-of-the-mill soap-on-a-stick that will gel and soften if you let it. This was crusty, petrified nastiness that wasn’t going to soften or dissolve unless you could somehow grind it into a fine powder.
I wasn’t up for that so in the bin it went. You win some and you lose some and this is why you experiment with small batches. But now I was hell-bent on making this coldprocess thing work so I headed back over to the drawing board.
Pine soap experiment #4
Obviously it wasn’t just the rosin and the high temp that had accelerated trace. I suspect the small amount of rosin acids in the tall oil fatty acids was enough to set the wheels in a spin. I suspect it might be the same rosin acids that make pine tar accelerate trace. So, I needed to make a plan to work around the anticipated acceleration.
With the room temp coldprocess method my temps were already as low as I could go. I was making unscented soap so I couldn’t eliminate any fast-moving fragrances. Coconut doesn’t really accelerate trace much so that was not a concern, but I now eliminated the small amount of castor oil because castor can cause spectacular acceleration. Finally I brought the water content up from 20% of oil weight to 32% of oil weight.
When oils and lye had cooled down properly I once again started adding the lye solution to the oils very gingerly, whisking continuously by hand. Again the lye solution seemed to saponify surrounding oil immediately and again I had a stiff paste by the time I had incorporated all the lye. The paste was getting so hot that I could feel the heat through my heavy-duty gloves and as expected it started gelling within minutes, becoming soft enough to spoon into the mould.
So, I was eventually able to make a coldprocess soap (of sorts) from tall oil fatty acids. 24h after moulding the soap was still so soft that I decided to give it another 24h before cutting. 24h after cutting the bars are firming up nicely but I’m still able to make an imprint in the soap with the pad of my finger. This is very unlike my regular coldprocess soap which is hard to the touch after 24h of pouring. I’m assuming the softness is largely due to the high water content. I normally soap with much less water so this aspect of the experiment has been quite fascinating.
In terms of what the soap feels like in use it’s still early days. The soap being quite soft, it dissolves easily, but it’s definitely less slimy than the first bar soap. The lather is rich with good bubbles as can be expected with 20% coconut oil and a fair amount of linoleic acid. I’ve showered with it for a couple of days now and it doesn’t leave my skin feeling tight or itchy. Very agreeable so far.
So, are tall oil fatty acids and gum rosin worth pursuing further as soapmaking ingredients? Definitely when it comes to un-superfatted cleaning soap. I’m mighty chuffed with my handmade un-superfatted mäntysuopa rag rug soap and I’m sure I’ll be making more in the future.
Given that tall oil fatty acids are challenging to work with I’m not so sure I would recommend them for skincare soap though. Where I am both tall oil fatty acids and gum rosin are more expensive than e.g. coconut oil. So price is not an incentive and I can formulate a combination of oleic acid and linoleic acid using other oils. The pine wood smell is lighter in the superfatted soap without rosin, but it still comes through loud and clear. While I love the mäntysuopa smell on my rugs, I have to say I’m not quite as fond of it in the shower. Yet, I prefer it to most pine-type fragrance oils I’ve come across.
In any case, soap made with pine wood oil is now off my bucket list and with my stash of mäntysuopa waiting to be used I have good reason to look forward to the winter rains.
And as a cherry on top – the little lime tree in my garden is now free of aphids.