Pine Tar scent changes when mixed with lye water

[cascader17]

Hello,

I'm experiencing a really vexxing problem that I am having a very hard time figuring out the reason for. I made some home-made pine tar using the tin-can/campfire method, and was quite pleased with the result. The tar has the consistency of molasses, and has a decent scent. However, when trying to make a batch of pine tar soap with this tar, the scent of the tar changes dramatically the second that it contacts the lye water solution (hot or cold). In fact, the reaction is so immediate that all that has to be done is dipping the end of a popcicle stick into the tar, and then immersing the tarred end into some lye water for a split second, and voila, the tar scent has changed from a smoky campfire smell to this terrible chemically scent that I can't quite identify. Does anyone know the exact reaction that could be taking place here, and if there is any way to avoid it? Is there a chemical in the home-made tar that is the culprit (phenols, etc?). Would there be a way to process the home-made tar in some way so that this reaction doesn't take place? For the record, I did try making an initial small batch of hot process soap with this tar, and after 2 weeks, the end soap product still has the unpleasant chemical scent. Thanks so much for any insights that anyone might be able to offer. Cheers!

 

[Zany_in_CO]

I've made pine tar soap but never even considered making the pine tar itself. I'm impressed! Good for you!

I know what you mean by the "smoky campfire smell" of PT -- it is a unique scent. The only thing I can think of that might cause it to smell weird after adding the lye solution is that's what happens with goat milk soap sometimes -- it smells like ammonia at first but the smell does dissipate after a while.

It would help to troubleshoot if you shared a printout of your recipe. Maybe there's something else in there causing the problem.

TIP: Take a look at @DeeAnna 's Soapy Stuff to see what she has to say about Pine Tar.

 

[cascader17]

Hi Zany in Co,

Thank you for your valuable and much appreciated input on this issue. The offending odor could very well be an ammonia-like one, but I'll have to double-check by taking a whiff of an ammonia cleaner product at the hardware store, just to confirm. At first, I thought it could have been due to some of my fatty oil ingredients, but after extensive trial and error testing, I determined that it is simply the pine tar and lye water that is causing this scent. Again, all I need to do is dip the end of a pine tar smeared piece of wood into some lye solution (for just a split second, too), and boom!, the scent is there big time. I also did another test, where I burned a little chunk of pine resin scraped from the bark of a pine tree (quite different from pine tar obviously), and then immersed the scorched piece into lye water, and the same scent was generated. When the same thing is done to an UNBURNED piece of sticky pine resin, there is zero bad scent. It tells me that when pine resin is heated, a new chemical is created that will produce an ammonia scent when combined with lye water. But what could it be? And is there a way to knock out whatever chemical that is? Or is it in fact a simple ammonia smell that will eventually dissipate after a long cure. You've given me a big clue, and I thank you!

 

[Zany_in_CO]

@cascader17 You're welcome.

@DeeAnna is our resident science guru. Hopefully she will be along shortly to advise you. I'm not sciencey at all so I'm no help there.

On another note, I use Oakmoss (10%) to neutralize the odor of animal fats in tallow and lard soaps. It's a wonderful "forest floor" scent that can stand alone or be used to anchor blends. It doesn't take much to offset odor and not be noticeable. My lard soaps just smell "clean".

Another thing about Pine Tar. The first time I soaped it, I was warned that it would trace in 27 seconds, and it did! It's definitely what we refer to as "a heater", meaning it heats the batch up fast once the lye solution is added. The same reaction applies to goat milk -- the sugars also cause that kind of reaction.

 

[earlene]

As I said in response to your entry thread, Wow! Making your own pine tar is really quite an endeavor. Kudos.

I do not particularly recall the actual intensity or how much it was altered during the chemical reaction of saponification of the pine tar soap batter at the start other than that it is much more intense at that time than after the cure. After a long cure, the odor is quite pleasant to my nose.

I am not really even sure of how much different certain brands of pine tar smell out of the can versus some of the others, as I have only used one brand. But I have read/heard that there is a difference in smell, which may have something to do with the source material as well as the extraction &/or manufacturing processes.

I would expect the odor of your soap will mellow in time, as is what tends to happen with pine tar soap, however one must also take into account that each of us may have differences in our olfactory sense, as it can vary widely in some people. Also the percentage of pine tar used could play a role in the intensity of the scent and how long it may take to mellow or fade.

I really do enjoy the scent of my pine tar soap, both when I unwrap the bar and in continued use.

 

[cascader17]

As I said in response to your entry thread, Wow! Making your own pine tar is really quite an endeavor. Kudos.

I do not particularly recall the actual intensity or how much it was altered during the chemical reaction of saponification of the pine tar soap batter at the start other than that it is much more intense at that time than after the cure. After a long cure, the odor is quite pleasant to my nose.

I am not really even sure of how much different certain brands of pine tar smell out of the can versus some of the others, as I have only used one brand. But I have read/heard that there is a difference in smell, which may have something to do with the source material as well as the extraction &/or manufacturing processes.

I would expect the odor of your soap will mellow in time, as is what tends to happen with pine tar soap, however one must also take into account that each of us may have differences in our olfactory sense, as it can vary widely in some people. Also the percentage of pine tar used could play a role in the intensity of the scent and how long it may take to mellow or fade.

I really do enjoy the scent of my pine tar soap, both when I unwrap the bar and in continued use.

Hello Earlene,
Whey you say "intense', do you mean the scent of pine tar was just stronger than what you can smell from the can? If so, it is likely because the pine tar has been warmed up, in which case it would definitely smell stronger. What brand of pine tar are you using?

 

[cascader17]

Hi Zany in Co,

Thank you for your valuable and much appreciated input on this issue. The offending odor could very well be an ammonia-like one, but I'll have to double-check by taking a whiff of an ammonia cleaner product at the hardware store, just to confirm. At first, I thought it could have been due to some of my fatty oil ingredients, but after extensive trial and error testing, I determined that it is simply the pine tar and lye water that is causing this scent. Again, all I need to do is dip the end of a pine tar smeared piece of wood into some lye solution (for just a split second, too), and boom!, the scent is there big time. I also did another test, where I burned a little chunk of pine resin scraped from the bark of a pine tree (quite different from pine tar obviously), and then immersed the scorched piece into lye water, and the same scent was generated. When the same thing is done to an UNBURNED piece of sticky pine resin, there is zero bad scent. It tells me that when pine resin is heated, a new chemical is created that will produce an ammonia scent when combined with lye water. But what could it be? And is there a way to knock out whatever chemical that is? Or is it in fact a simple ammonia smell that will eventually dissipate after a long cure. You've given me a big clue, and I thank you!

Well, it seems that the offputting scent coming out of my pine tar/lye water mixture is definitely an ammonia one. I had a chance to smell some ammonia based glass cleaner yesterday, and the two scents are quite similar to each other. There are around 300 distinct chemicals in pine tar, and one or more of them is reacting with the lye water to produce ammonia. Now if I can just figure out which ones they are, and then see if it's possible to take them out.

 

[earlene]

Hello Earlene,
Whey you say "intense', do you mean the scent of pine tar was just stronger than what you can smell from the can? If so, it is likely because the pine tar has been warmed up, in which case it would definitely smell stronger. What brand of pine tar are you using?

I use Horse Health brand: Pine Tar | Hoof Care Topical Antiseptic | Horse Health Products

Also I use it at 10%

Well, it seems that the offputting scent coming out of my pine tar/lye water mixture is definitely an ammonia one. I had a chance to smell some ammonia based glass cleaner yesterday, and the two scents are quite similar to each other. There are around 300 distinct chemicals in pine tar, and one or more of them is reacting with the lye water to produce ammonia. Now if I can just figure out which ones they are, and then see if it's possible to take them out.

I doubt the ammonia odor will remain. When I clean with ammonia (not often, but when I was younger, I used to use it more often than now), the odor does not remain forever. Of course, it was in cleaning solution as opposed to in a solid bar of soap. But I do recall past discussions about using ammonia in soap; apparently it was preferred at some point in the past for use in laundry and cleaning soaps. Here is some information on that if you are interested: (link) And a search here at SMF shows results of makers still active today who have made laundry soap containing ammonia, so people use it. Perhaps @lsg can respond if you want to ask her about how long the ammonia odor remained in laundry soap that she used to make. It was bar soap that she made, but it was quite a long time ago. (See this thread.)

 

[cascader17]

I use Horse Health brand: Pine Tar | Hoof Care Topical Antiseptic | Horse Health Products

Also I use it at 10%


I doubt the ammonia odor will remain. When I clean with ammonia (not often, but when I was younger, I used to use it more often than now), the odor does not remain forever. Of course, it was in cleaning solution as opposed to in a solid bar of soap. But I do recall past discussions about using ammonia in soap; apparently it was preferred at some point in the past for use in laundry and cleaning soaps. Here is some information on that if you are interested: (link) And a search here at SMF shows results of makers still active today who have made laundry soap containing ammonia, so people use it. Perhaps @lsg can respond if you want to ask her about how long the ammonia odor remained in laundry soap that she used to make. It was bar soap that she made, but it was quite a long time ago. (See this thread.)

Thank you, Earlene, for all of your tips and information. I appreciate your insights tremendously. The test run batch of pine tar soap I made does seem to be mellowing a little bit, about 3 weeks after it was produced. Hopefully, this trend continues, and ends up yielding an ammonia-free bar. And thanks for the tip about the Horse Health product, something I might need to get a hold of. One approach I might try is only adding the pine tar additive at trace, and then quickly mixing it with a stick blender, prior to a mold pour. That way, much of the lye will have saponified before pine tar exposure, in theory anyways.

 

[AliOop]

One approach I might try is only adding the pine tar additive at trace, and then quickly mixing it with a stick blender, prior to a mold pour. That way, much of the lye will have saponified before pine tar exposure, in theory anyways.

If you go that route, I would use a whisk and not a stickblender. You will probably have less than a minute to get it stirred in and molded before it is just too thick.

 

[DeeAnna]

... adding the pine tar additive at trace... That way, much of the lye will have saponified before pine tar exposure, in theory anyways.

It's a myth that the alkali (NaOH, KOH, etc.) is mostly consumed by the time the soap batter is at trace. All trace means is there's enough soap in the batter to chemically emulsify the batter so you can stop mixing mechanically. There's still a lot of active alkali still in the batter at that point. Kevin Dunn and his students did experiments that debunked this myth.

I agree with AliOop about stirring with a whisk or spatula, not a stick blender, if you go this route. I've tried mixing the PT in using several different methods. Adding pure PT to the soap batter after the batter is emulsified is the least satisfactory method I've tried. It's tough to get the PT mixed in well and have the soap batter remain fluid enough to pour. But that's just my experience -- YMMV.

 

[AliOop]

I agree, @DeeAnna that method is stressful and frustrating. I much prefer melting the pine tar with all the oils, and then mixing in all the other additives, before adding the lye solution.

 

[cascader17]

If you go that route, I would use a whisk and not a stickblender. You will probably have less than a minute to get it stirred in and molded before it is just too thick.

Thanks for that advice. I think I'll try using a whisk just to see for myself how effective it is.

 

[cascader17]

It's a myth that the alkali (NaOH, KOH, etc.) is mostly consumed by the time the soap batter is at trace. All trace means is there's enough soap in the batter to chemically emulsify the batter so you can stop mixing mechanically. There's still a lot of active alkali still in the batter at that point. Kevin Dunn and his students did experiments that debunked this myth.

I agree with AliOop about stirring with a whisk or spatula, not a stick blender, if you go this route. I've tried mixing the PT in using several different methods. Adding pure PT to the soap batter after the batter is emulsified is the least satisfactory method I've tried. It's tough to get the PT mixed in well and have the soap batter remain fluid enough to pour. But that's just my experience -- YMMV.

I was wondering about this exact subject, the degree to which the lye is consumed by the time the trace stage is reached. Thank you. I also wonder about the degree to which the NaOH is depleted by the pine tar to ammonia reaction. Does whatever compound in pine tar that reacts with NaOh to produce ammonia leave less of the NaOH for saponification, resulting in softer partially saponified soap? The first and only batch I've made so far definitely seems a lot softer than what I expected, almost as if saponification hasn't happened fully.

 

[AliOop]

My understanding is that while pine tar does react with NaOH, it doesn't saponify per se, and that's what makes the soap softer. I compensate by using a good percentage of tallow, as well as palm oil in my latest batch. The finished bars are significantly harder than the ones made with lard and OO.

 

[earlene]

Does whatever compound in pine tar that reacts with NaOh to produce ammonia leave less of the NaOH for saponification, resulting in softer partially saponified soap? The first and only batch I've made so far definitely seems a lot softer than what I expected, almost as if saponification hasn't happened fully.

Remember that if you add 10% of something that is soft & gooey (like pine tar) to anything that is normally much thicker (or hard, like bar soap becomes), it will dilute the thickness (or hardness) to make a resulting softer (or less hard) solution (or bar of soap.)

When the pine tar is 10% of oils, the NaOH is calculated to saponify the oils, only a tiny amount of NaOH is actually interacting with the pine tar.

Test out the formula for yourself: Create a recipe with 100% oils and no pine tar. Then using that same recipe, add in 10% pine tar. Compare the amount of NaOH the calculator gives you for the two different recipes. You will see that the amount is only very slightly different, but the liquids added in the recipe are equal in weight. It only makes sense that replacing 10% of the oils with pine tar will create a softer bar. It is not a partially sonponified soap. The oils still saponifiy, but another ingredient (pine tar) that does not saponify is taking up space in the soap, which is what makes it softer.

You can use less pine tar (5% perhaps) to make a harder bar of pine tar soap. Or you can use a harder fat, as AliOop suggests. Or you can use a combination of both, to create a harder bar.

I have not tried any of the other methods for hardening bar soap with pine tar soap, but perhaps one day I will try substituting vinegar for part of the water to create Sodium Acetate, which creates a harder bar of soap. Salt would also harden the bar, but again, I have not added salt to a pine tar soap either, and expect it would be at least a bit harder. Either of those additives with pine tar may possibly be problematic and I would not recommend them for a beginner.

 

[MickeyRat]

I do make pine tar soap on occasion. I never attempted to make my pine tar from scratch though. DeeAnna has a web page that describes how to make it and it's what I do. I've never noticed a change in scent.