Best temperature at which to add FO

[CandleCouture]

I know that 175-180 is usually deemed "optimal" for adding FO as this allows the Oil to bond with the wax properly, but, out of curiosity, has anyone conducted tests on this? I plan, in the next two to three weeks, once wick testing is complete, to start testing, one batch which will receive FO at 175-180 and another one (with the exact same container, wick, wax, etc) to which FO will be added much cooler (maybe 140-150). I'm curious to see if the difference is drastic.

Has anyone else conducted this type of test or experiment?

[topofmurrayhill]

One of the content authors on About.com claimed to have done this type of test and concluded that 180 was the tipping point at which an improvement in scent throw could be discerned.

I guess you could say I've accepted this on a "just in case it's true" basis, but I've always considered it to be one of the many things in candlemaking that deserves more research.

People talk about "binding" but I don't think anyone can explain what that's supposed to be. FO has to be dissolved in the wax. The solubility of fragrance oils varies and some of them definitely need heat to dissolve, but the majority appear to form a transparent homogeneous solution at temperatures much lower than 180. Since I don't understand what this extra "binding" step is supposed to be, I take it with a grain of salt.

I applaud your initiative with this. If you discover anything interesting I hope you will share.

[CandleCouture]

Top, I couldn't agree more. I've never been the type of person to simply accept things as true, without any real proof. That's not to say that I will disprove this (as I don't really WANT or NEED to disprove it), but I would still like to see for myself.

Furthermore, all things being equal, if, in fact, it turns out that I get the same scent throw adding FO at 150 as I do by adding at 180, I would prefer to add at 150, if only because it makes me feel better about any FO being burned off by adding at such high temperatures.

Chemically speaking, I'm not sure what this "bindging" is really supposed to be, as, in essence, all you want is really a fragrance oil that dissolves and mixes, completely in the wax, without any separation. Whether or not mixing at the higher temperature aids in this is what I'm going to look for.

Now if only I could somehow gauge scent throw in a subjective manner. If only there were a "scent meter" that I could buy, it would make this even more precise. Oh Well.

[Hope]

I did an exp. similar to the about.com one. But it was a small, garden variety exp.. Only varying factor was fo introduction to wax. The hotter temp. did seem to have the more desirable hot throw as well as other results. Chemical compostitions, which Top seems to have alluded to regarding the fo, would definately need some attention in a more precise exp.. Namely b/c waxes and fo's have different structures than other waxes and fo's. A more detailed, controlled exp. is in the works for the future.

About the terms, bind seems to be a laymen's term for the the chemical processes which occur. It seems that what really seems to be occurring is the heating of the wax encourages the solubility of the fo. So, that a feasible saturation is achieved. Ex: Hot water has a higher saturation point for dissolved sodium chloride than cold water. As well as ease of dissolvability in the hot vs. the cold.

[Crafty1_AJ]

All I know is that when I used to add the fo at cooler temps (about 150), I'd often have a nice big puddle of fo at the bottom of my container candles. When I started adding fo at a hotter temp, no more puddles of unincorporated fo.

[MasterBaker2]

All I know is that when I used to add the fo at cooler temps (about 150), I'd often have a nice big puddle of fo at the bottom of my container candles. When I started adding fo at a hotter temp, no more puddles of unincorporated fo.

My experience too.

[CandleCouture]

And, I'm assuming the stirring was the same? If so, then the question becomes, what is the VERY lowest temperature you could add FO, at which the oil would incorporate fully into the wax? Is it 155? 160? 170? I suppose that finding that ideal number would be important, as the lower the temperature, the less amount of FO that is burned off.

[topofmurrayhill]

And, I'm assuming the stirring was the same? If so, then the question becomes, what is the VERY lowest temperature you could add FO, at which the oil would incorporate fully into the wax? Is it 155? 160? 170? I suppose that finding that ideal number would be important, as the lower the temperature, the less amount of FO that is burned off.

The reason I haven't minded treating the 180 thing as tentatively true is that (a) I often need to heat the wax at least that high anyway and ( I'm certain there's no significant fragrance loss from evaporation. That process is FAR too gradual to be of concern while pouring the wax. Seems to me this question might mostly apply in the context of vegetable wax since it's often poured real cool.

[NattyCat]

just to add confusion to the conversation, when I first started out making candles, all the instructions I read said that you should add your FO just before pouring. Well, this is what I did whilst also following the instructions that you shouldn't pour until the candle is approaching "slushy" stage.

When I added the FO at just before slushy, the FO formed a milky white pool in the wax but with a bit of vigorous stirring and then letting the wax settle for a while to get rid of air bubbles, the FO was completely incorporated. After curing, my candles still had hot and cold throw.

On a few FO's I found that I had no throw at all, so asked on the forums about it and was told to add my FO at much higher temperatures. I then started adding the same FO at 175...and STILL had no throw, so I think the FO I was using simply didn't throw in soy.

I now pour my FO at 175 simply because I was told that it was the right thing to do - but it my experience, it didn't make any difference to the throw - I found that if the FO threw in Soy, it threw in soy no matter what temperature I added it at. I'm sure that I've probably added an FO at 175 that I've never tested at the lower temperature, so there may be a difference on some FO's.

I think the answer to this is the same with wicks - you need different sorts of wicks for different sorts of candles/waxes/FO's so you test test test. With FO you need different adding temperatures for different FO's so the obvious solution would be to test all your FO's at hot and cool adding temperatures.

Probably a wild guess, but perhaps thicker & heavier FO's need to be added hotter to break down their consistency, and lighter FO's can be added cooler as they mix with the wax easier and quicker?

Nat

[Beth-VT]

I don't see it as an issue of 'throw', at leat not directly. The term bind is used more to mean incorporate, or combine, or blend or whatever.

In the simplest terms, warm oils will combine much easier than cool oils. YOu probably don't notice much difference in throw, because the oil IS in there, and as long as you have a full melt pool and a hot enough wick, chances are there is a significant enough amount of FO in that melt pool to create throw. The problem with adding oil too cool, as mentioned above, is the oil not incorporating thoroughly with all the wax, thus creating pockets of oil in the candle. Even using all the same methods as usual, like stir stick, time stirred, etc., if you've ever seen a pocket of oil, you will instantly realize why a warmer temp is preferred. It's not pretty, and can be dangerous.

It's true that different oils may have a different temp at which they will incorporate into the wax, but who wants to keep track of "i can add this FO at 140 but this one at 175", etc. It's simply easier to set a base line at which the tougher oils blend, and obviously there will be no problems with lighter oils. 180 seems to be a good point. That doesn't mean that 170 wouldn't work, but if you use 170 then why not 160, and if 160, why not 150, etc. Without some pretty technical testing, there's no way to determine exactly, and yo'd pretty much have to test every oil to be able to say it works. Visual ID of complete blending I don't think is accurate. Heavy oils may appear to blend well, but when they don't, well....you know it. 180 also seems to be a good point at which the heat doesn't have an impct on burning off the FO, at least not over the short term. Burn off doesn't seem to happen until closer to 200 and that's over a period of time. A couple of minutes even at that point will have no effect.

As for where these temps come from? Experienced chandlers. Although not scientific by any means, these temps come from experience. Hundreds of chandlers who've made thousands of candles using hundreds of different oils. Experience over time. The numbers are not just something pulled from a hat. Although many newer chandlers may be using these temps 'just because" they've read then somewhere, over time they see the cause and effect.

Natty, it sounds to me like you're pulling from recommendations created at different points in time. For years, the general guideline has been to add FO jsut before pouring. And for the most part it still is. What this means is to add your FO as the last item, so that the oil is subjected to the least amount of heat necessary. If you use an additive that needs 200+ to melt, then the object is to add those first, THEN add the FO as the temp is coming back down. You wouldn't want to add the oil, then heat up to 200+. There's certainly no 'rule' about it, it just depends on what you're using. 'Just before' doesn't mean dump the oil in, stir twice, then pour. You add at a warm enough temp, blend well, and let it cool down to your pouring temp. Once you've removed from heat, you run no danger of burning off any oil.

Now days, the definition of "just before" has changed due to the popularity of soy waxes. They, for the most part, work better at very cool pour temps of as low as 100 degrees. You obviously can't add your oil 'just before' in this case. Before soy waxes, it was impossible to pour anything at 100, so the term 'just before' was appropriate.

The implied meaning is to add your oil at a time when it will no longer be subjected to extreme conditions, but will still blend well. If you add your oil at 180, blend, and let it sit at 150 (for example) for half-an-hour before pouring, the world won't stop spinning, and your candle will be just fine. HTH.