Hot process vs cold process

Discussion in 'Beginners Soap Making Forum' started by elvira, Jun 16, 2019.

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  1. Jun 16, 2019 #1

    elvira

    elvira

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    Regarding the quality of the soap itself, (not the difference in the making procedure and being able to add swirls, effects aromas etc)) what is the difference in the quality of the soap: mildness, mosturizing propierties, getting stains, lasting of the bar etc.
     
  2. Jun 16, 2019 #2

    Obsidian

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    There is none. HP can take longer to cure and dry since its usually made with more water then CP but thats it.
     
  3. Jun 16, 2019 #3

    Bladesmith

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    I'm still a budding newbie but I'd say if you have the same recipe, you're going to get the same soap regardless of process.

    Being that I'm a HP'er, I'm a little biased. I'd also say that you have a little more freedom with ingredients with hp since you don't care about acceleration (like really high amounts of butters or stearic, etc). Also you can put things in after the cook that might otherwise be sensitive to the lye monster. Or high amounts of sugar without worrying about it getting hot, etc. So from a performance perspective, you might choose a recipe that is not possible or very difficult to do via cold process and could give you different (not necessarily better) results.

    One of the "perks" of hp is being able to select superfat by adding it after the cook. This might affect moisturizing/conditioning/less stripping qualities of your soap. Probably not super noticeable though.

    Like I said earlier though... same recipe, same soap regardless of process.

    Just my $0.02 from a newbie soaper :)
     
    Last edited: Jun 16, 2019
  4. Jun 16, 2019 #4

    earlene

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    I'd have to agree. It's all about the recipe AND a good cure, not the process when it comes to quality of the soap.

    But I don't understand the question about getting stains.
     
  5. Jun 17, 2019 #5

    IrishLass

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    Right here, silly!
    Ditto! Considering you are using the same recipe, you'll have the same outcome in terms of qualities after cure, no matter the process used.


    IrishLass :)
     
  6. Jun 17, 2019 #6

    MGM

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    In theory, wouldn't anything added post-cook in HP retain more of its "therapeutic" properties because it doesn't go through the lye monster? So, choosing your superfat oil, as @Bladesmith mentioned, but also anything with milks or botanicals or something like that? So while you could have the same recipe on paper, aren't some things preserved in HP (when added post-cook) that are lost in CP?
     
  7. Jun 17, 2019 #7

    DeeAnna

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    The alkalinity (in other words, the high pH) of soap is still an issue even after the soap is fully saponified. If it wasn't, those cute lavender buds wouldn't turn into mouse poo, vanillin would not darken, and scents would not morph. And so on.

    While I'm sure some ingredients can remain intact if they are added after the cook, I don't think it's realistic to expect they will without measurable proof. Wishful thinking and hoping doesn't make it so.

    That's especially true, IMO, for ingredients that are supposed to be "therapeutic". The reason why these ingredients are beneficial is that they are chemically reactive in order to provide those benefits. Highly alkaline or highly acidic environments can be tough on ingredients like that.
     
  8. Jun 17, 2019 #8

    earlene

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    And then there is the whole 'wash-off' product reality with therapeutic additives.

    Even if they believe the ingredients are still intact in the high pH environment of soap, there probably aren't a lot of people who slather on the soap and just leave it on the skin to absorb whatever therapeutic ingredient they believe will provide benefit.

    The only time I ever leave soap on me for an extended period of time, is my prescription shampoo (which is probably not even soap anyway), which I cover with a shower cap to allow for the medicine to do it's work (for the specified amount of time, per Dr's orders.)
     
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  9. Jun 17, 2019 #9

    MGM

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    Oh I didn't mean to imply that the soap itself would have any therapeutic value; I'm not even sure the compounds do, which is why I put it in quotation marks. But it seems to me that the role, and perhaps eventual chemical make-up, of yogurt in CP vs in HP, for example, would mean that the bar had different properties, as OP initially asked.
    But, as @DeeAnna said, maybe alkalinity uber alles!
    Which makes me think that perhaps most of a soaper's ingredients used in small quantities are for label appeal?
     
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  10. Jun 18, 2019 #10

    DeeAnna

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    I'm inclined to agree with you, @MGM. Most of the special ingredients I use are mainly for fun. Ignoring the HP versus CP debate and just looking at how additives perform in soap, here are some of the things I've tried and what I think of them --

    Poking at sacred cows -- I can't say I've seen much difference when I've added dairy milk to soap. Ditto for coconut milk. I account for the added coconut oil in the CM when designing my recipes. I know others don't, so the added superfat might explain the difference.

    I think beer adds to the ease of lathering and the quantity of lather. It can darken soap depending on how dark the beer is. I do not think beer changes the hardness or longevity of the soap.

    I think egg adds color (well, the egg yolk does) but I'm still trying to decide if it does anything much more than that.

    Neem and pine tar may have skin benefits, but not if you do the usual wash-and-rinse method of bathing. A person needs to leave the lather on the skin for awhile like Earlene explained to see any benefits.

    Neem makes a nice bar of soap -- it's similar to lard or palm in its fatty acid makeup, so it makes a hard, long lasting bar. If you don't mind the distinctive smell of neem, it's truly a nice fat to soap with. Neem will darken the soap to a caramel color.

    Pine tar tends to make soap softer, so pine tar soap doesn't last as long in the bath, all other things being equal. And, of course, pine tar turns the soap a dark brown and adds its famous smoky or burnt rubber odor to the soap.

    Rosin is a weird additive. It's one of the few ingredients that pretty much has to be used with a hot process method, because rosin melts at higher temperatures and saponifies very, very fast. Rosin soap will volcano on you in an instant if it's not watched like a hawk and stirred down quickly. Rosin soap is hard and lathers better compared to the same recipe without rosin, but rosin doesn't add any special skin benefits. It darkens the soap to an amber or golden brown shade. I don't think the advantages of using rosin outweigh the disadvantages.

    Of all the additives I've tried, lanolin in the 3% to 5% range definitely leaves a slight but detectable film on the skin after normal wash-and-rinse bathing or when used in a shave soap. This film isn't enough to replace lotion in dry winter conditions, but it helps to soothe and soften the skin a bit. I don't think I'd want much more lanolin than 5% or so. My concern is too much lanolin is likely to make the skin feel waxy or sticky after bathing. I would also be concerned that lanolin would soften the soap itself at higher percentages, since very little of it saponifies.
     
    Last edited: Jun 18, 2019
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  11. Jun 18, 2019 #11

    MGM

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    @DeeAnna thank you for the fantastic round-up (as usual) Follow-up question re: your final point: lanolin. I have some that I've been wondering what to do with....you're talking about using it in CP, right, not as an additive in HP after cook?
    Might have to try a filmy soap.... 3-5% only though, you say?
     
  12. Jun 18, 2019 #12

    DeeAnna

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    Yes, I've used lanolin only in CP soap, but I'd be totally comfortable putting in HP soap too. I'd treat it just like a regular fat (although it's not) so the small amount of lye it consumes is figured into your recipe, whether you do HP or CP and whether you add at trace or after the cook or right up front as I do.

    I've only used lanolin in the 3% to 5% range. I'm currently using it at 5%, and I like it at that percentage. The film is detectable, but it feels light and not at all sticky. I suppose I should evaluate it at, say, 7% and 10% just to know how it performs, but I'd want to do a small test batch at those percentages in case the skin feel is not good.
     
  13. Jun 18, 2019 #13

    earlene

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    For my Liquid Shaving Soap, I use 6% lanolin. It seems to be just about perfect at that percentage in LS specifically for shaving as I have not nicked myself shaving since I started using this soap in 2015. That's a pretty good record for me, who used to cut myself shaving almost every time I shaved before that. But it's an LS.

    In bar soap I used 5%, and liked it at that percentage. I haven't made any soap with lanolin in awhile and don't have any of the bars left anymore. I used it in HP soap when I first soaped it in bars, but as long as the other oils don't require higher temperatures (such as when I added stearic acid in a soap with lanolin), then CP would be fine, too.
     
  14. Jun 18, 2019 #14

    DeeAnna

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    Glad to see you and I are in the same ballpark for the percentage of lanolin, @earlene. Yes, I do HP when making shave soap because of the stearic acid. Lanolin is nice in shave soap; I've used it at the same 5% as for bath soap.

    FWIW, I did a short video about making "farmhouse soap" that has egg and lanolin in it -- The egg is more trouble to add than the lanolin in this recipe, although egg is not hard either, to be honest. I warm the lanolin in a hot water bath until it's liquidy and pourable -- it's very sticky and a pain to work with at room temp -- and then weigh it into my other fats.
     
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  15. Jun 18, 2019 #15

    Tara_H

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    Fascinating! I'd love to hear about it when you decide if the eggs do more than just add colour; we keep chickens and we always have more eggs than we know what to do with (mostly give them away) so it would be great if one hobby contributed to another :D
     
  16. Jun 18, 2019 #16

    DeeAnna

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    So far I've always added lanolin and egg together to create a "farmhouse" theme of using ingredients from sheep, hogs, chickens, etc. The base oils for this particular soap are exactly the same as for my other recipes -- I just added the egg and lanolin to my usual recipe.

    The soap is distinctively different, in that I can feel the lanolin film on my skin after my shower. Also the soap bar and the lather it makes are slightly different too. But I don't know if the differences are created by the egg or the lanolin or both. I'm inclined to say it's mostly the lanolin, but I honestly don't know that. I need to do an egg-only soap.

    I think @earlene has done egg alone in soap, and liked the results as far as mildness. Maybe she will share her perspective.
     
    Last edited: Jun 18, 2019
  17. Jun 19, 2019 #17

    earlene

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    Tara_H, I found eggs in soap to add a sort of buffering effect to the harshness of a high cleansing soap. Without the eggs, I found high cleansing soaps pretty harsh, but with the eggs, much milder. And eggs definitely contribute to bubbles and lather. Just run a little water into a bowl in which you scrambled eggs and you can see loads of bubbles forming and frothing as the water hits the leftover egg bits.

    Of course, decreasing CO (or other high cleansing oils) can reduce the harshness. And adding sugar can increase bubbles. And some of the fat in eggs does contribute to the SF (super fat) in the soap, so that's obviously part of decreasing the harshness (for some people's skin). But for my skin, even a high SF high CO bar of soap can be too harsh. So if all else is equal, just adding SF from eggs doesn't account for decreased harshness in the soap. It's adding more to the gentleness and mildness of the bar than extra SF.

    Perhaps it is the remnants of the different proteins or other nutrients in the eggs that remain in the soap after the lye and other chemical reactions do their thing, that creates this mildness and sort of conditioning feel to the soap. I don't have the necessary training to break down the chemistry of it all. I just know I have found eggs in soap really contributes to making it a nicer soap, whether whole eggs, or only part of the egg.

    Egg yolk or whole eggs, both contribute yellow color that lasts for at least 4 years, and my guess is, for the life of the soap. (The oldest egg soap I've got is 4 years.) Egg whites lend either no color or perhaps enhance the whiteness or perhaps just don't interfere with the whiteness of an oil mix. My oldest egg white soap is very white and is about the same age as the yellow egg soap. Neither soap was colored with any added colorant.
     
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  18. Jun 19, 2019 #18

    Tara_H

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    Thanks for the detailed reply! That's very interesting, I was planning on trying a HP solid soap this evening (if the stars are in my favour, lol!) but now I'm very inclined to try a CP egg soap and see how that comes out.
     
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  19. Jun 19, 2019 #19

    DeeAnna

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    "...And some of the fat in eggs does contribute to the SF (super fat) in the soap, so that's obviously part of decreasing the harshness (for some people's skin)...."

    There is about 5 grams of fat per yolk, so if you add 1-2 yolks per 500 g / 16 oz of fat and don't account for the added fat when calculating the recipe, the added yolk fat will increase the superfat by 1-2%. Yolk fat has a saponification value similar to canola, so you can include 5 grams of "canola" per yolk if you want to include this fat in the lye calculations (I do). The fatty acid profile of yolk fat is more similar to emu oil, however.

    I have to say my egg-lanolin bath soap does lather beautifully, compared with the same recipe without egg or lanolin. The lather starts quickly with little effort and is an appealing mix of fluffy bubbles and whipped cream foam. The bar (when wet) and the lather both have a slick, velvety texture that feels good in the hands.

    I think if I gave a person off the street a chance to wash hands with this soap and then wash with the base soap (the soap made with no egg, no lanolin), they might be able to pick up on the difference in the texture of the lather. That said, I've noticed we pay a lot more attention to things like this than the average person, so this difference in lather is probably not going to be a thundering revelation to anyone not a soap maker. ;)
     
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