Opinions on preservatives

[Vonna]

Does CP soap really need a preservative? What is everyones take on this? If there is no preservative added how long is the shelf life? I know it would be different for every soap but I just made an oatmeal and cinnamon bar and was a little curious as to how long the oatmeal would hold up?

 

[Lindy]

I don't use preservatives because I figure since the lye monster turns the oils into salts and salt is a preservative there is generally no need - that is however just my opinion and it doesn't mean I'm right..... 8)

 

[Vonna]

That sounds good enough for me!! I didn't really want to use a preservative

 

[Tabitha]

It turns oils into salts, but what about wet oats?

 

[Lindy]

Hey Tabitha - fair enough - does the salt not preserve oats as well since the oats are encased in the salt except for what's on the exterior of the bar?

 

[IrishLass]

The general consensus among the majority of handmade soapmakers on all the soaping forums I frequent is that it's not necessary to add preservatives to CP. I never have, not even in my foodie soaps, and I have never had a problem with them going bad or rancid, except for 1 batch that I got DOS in (too much canola with a high superfat). I've only been soaping for 2 1/2 years, but I've saved a bar from each of my batches, and except for that 1 DOSed batch, they are all still good, even the bars from my earliest batches 2.5 years ago, or almost 200 batches ago. (That's a lot of bars! Help! I need more room! ).

In regard to foodie soaps like oatmeal, avocado puree, cuke puree, carrot puree, etc...- the trick is to finely puree the food and stay within the ratio of using only 1 tablespoon of it ppo. If you stick to those parameters you'll be good to go. There are soapers I know of who have gotten mold in their foodie soaps, but it turns out from further investigation that they happened to have used chunks of food instead of pureed food. You definitely want to get your food as fine as possible so that the lye can completely encompass every layer of it enough to keep the buggies at bay. It can't do that if your food is in chunks, and so the chunky food in those soaps get moldy.

HTH!
IrishLass

 

[Vonna]

Wow..Thanks IrishLass! That answered alot of my questions. And yeah, it sounds like you need more room My hubby and I decided until we have another baby...our spare bedroom can be mine to cure and store all my goodies The rate I'm going I'm going to need the whole garage!! I've only started cp soaping in the last 7 days and I've already done 6 batches! I'm definitely addicted!!

 

[kaseencook]

It sounds like there are two different things here.

DOS, which is the oxidation of oils and has nothing to do with bacteria and perserviatives (Adding antioxidants can reduce this),

and bacterial/fungal growth which is what you would need a preservative for.

My husband is a microbiologist and we have had several discussions about bacterial/fungal growth in soap.

Our general consensus was that in the soap it's self, like Lindy said, there may be water around (like when the soap gets used), but the water MAY not be available for bacterial growth - like when it snows and the plants cannot use the water because it is not available, it is frozen and the ground is dry. But of course it is not sterile so there is likely always small numbers of bacteria that can live in the conditions of the soap, but there is probably competition with other bacteria for the limited amounts of usable resources, as well as less than optimal conditions for extreme bacterial growth (to the point where it would decay), and conditions that can change frequently when in use.

We think that it would be more likely for a fungi or mold to grow on the soap's organic bits, and be more noticeable than bacterial growth, as a fungal hyphea can usually be seen with the eye compared to a bacteria. But even if these things are present they are not always visible. Probably because the soap is being used to frequently and they are getting washed and disturbed, or drying out, or the conditions are always changing and it cannot survive for long enough to grow to a visible size.

There are just so many factors, and they often change.

Personally we have never had visible growth on our oat soaps or soaps with plant materials in them - HP soap with oats and plant stuff added after cook. I have heard of people with fresh flower petals on top of molding in the packaging, but that would happen regardless of the soap factor, and it is likely that the environment was consistently moist with available water (non soapy) from condensation on the wrapper and in a consistent temperature, most likely warm room temperature.

And if the soap is dry, bacterial and fungal growth is very unlikely as of course most bacteria and fungi need water to grow. Even if they are present, they don't have the resources to grow up to a noticeable amount.

But these are all just theories based on our observations of our soaps (including oat soaps), observations of how other micro organisms grow from Michael's work, and we had to assume the micro-conditions of the soap as we don't really have any way of actually testing the amount of available water or micro-nutrients in the soap.

But anyway, these are just theories and ideas and stuff that we have been thinking about

 

[Lindy]

With my food soaps I always grind everything up really fine - I turn my oats into a powder & puree my fruits). I have always understood that the lye takes care of it as long as it can reach through everything which is why I have never tried chunking it. With rebatching when you add fruit or food items I think then you have to use a preservative - but what about HP if you add the food stuff at the end? Since the lye monster has been tamed?

 

[Guest]

I don't use preservatives very often , GSE if I think there might be a problem with the additive.

Kitn

 

[kaseencook]

Although I can see lye initially killing some bacteria in organics, it would kill them by "digesting" them and if it is digesting the bacterial cells it should be digesting the plant cells as well (and turning your organics into brown stinky goo). If your organics are not being digested it is likely the bacteria are not being digested either. I used to work sterilizing endoscopes at the hospital, and one sneaky aspect of bacteria is that they can from a biofilm, where bacteria pile up in little clumps sometimes in nooks of debris, and are protected from sterilizing chemicals (which is why we had to both manually and chemically clean endoscopes with a special biofilm remover).

I guess what I am trying to say is that there will always be bacteria and fungi/mould in the organic bits, even if they are very small, bacteria and spores are much smaller. The key is that the organics, like oats, generally dry out on the surface of the soap (especially since they are generally dried when added), which deters growth by aerobic bacteria.

I add whole oats to HP after cook, as well as dried herbs, and there has never been any issues with growth - it it just to dry, and most oats are coated in soap - so growth is only likely to happen via anaerobic bacteria, but the water in the soap does not penetrate the oats very well - so again not enough water for most bacteria to do much damage. Especially with discounted water.

Unless you are adding very wet organics like fresh fruit, leaves/herbs, or vegetables (which would certainly grow noticeable fungi/mould and bacterial growth if they do not dry out in about a day or two), I would not be concerned about dried organics.

This is what I have observed with my HP oat and herb soap anyway.

 

[surf girl]

Re DOS and preservatives:

I can't remember who gave me this link (might have been someone here - I can't recall), but it describes a controlled experiment which compares various hypothetical methods of preventing DOS, specifically lye discount/superfat and preservative additives.

The preservatives that made a significant difference were:
- rosemary oleoresin extract
- EDTA
- to lesser but still significant extent, BHT.

Things that made no difference were:
- Grapefruit Seed Extract
- Vit E
- Vit C
- sodium citrate
- changing the superfat from 10% down to 0%.

http://cavemanchemistry.com/HsmgDos2006.pdf

 

[kaseencook]

DOS can only be combated with antioxidants, as it is due to the oxidation-reduction reaction of the unsaturated fats that did not soaponify - so preservatives would not help as they are for micro-organisms.

This shows a good pic of the oxidation of a lipid, which results in a stinky yellow peroxide:
http://en.wikipedia.org/wiki/Lipid_peroxidation

The substances that worked for DOS in that list are high in antioxidants - like rosemary. Although, Vit E is used in food and oil based drugs (like primrose oil) to help prevent oxidation of unsaturated fats, it is often listed on the ingredients label. Check out this link under "functions":

http://www.ghchealth.com/vitamin-e-tocopherol.html

Other natural substances that I have found are high in antioxidants and help to reduce DOS as oat flour, green or ceylon tea, cinnamon, cloves, cocoa powder.... there are a lot of of other natural substances out there as well that may work well, like ginger. There is a list of substances with high ORAC values:

http://oracvalues.com/sort/orac-value

 

[surf girl]

You may have a more strict definition of "preservative" than is in common use? I do understand what you mean re prevention of oxidation vs prevention of microbial growth, but I would have grouped antioxidants under the big umbrella of "preservative" since they preserve the fatty acid salts from oxidation.

Shrug. It was just a list to note a better-than-hearsay evidence for what will and what will not help slow down the development of DOS.

 

[kaseencook]

I'm sorry, about that! I was out of control, like a soaper let loose in an oils shop!

I definitely see what you mean

 

[surf girl]

I was out of control, like a soaper let loose in an oils shop!

Now that's an image I can totally relate to! (What, who, me?)

 

[kaseencook]

he he he!

That would be fun though! So many combinations! Wooo HA HA! :twisted: