Why dos at 3 months?

Hi everyone. One of my favorite recipes has dos at exactly 3 months of age. The 2 bars I have left were stored in 2 different locations, one was much lower in humidity than the other, but both have developed 1 spot of dos at the same time. Can you help me identify the cause; I'd really like to try to save this recipe.

At 6% sf:

oo 25, co 17, lard 15, palm 15, mango butter 10, shea 10, castor 8. I'm not sure, but I think the olive oil was the unadulterated Costco oo. I made this in June, and that's about the time I threw out the cheap oo.

Colored with td, purple mica, scented with lavender eo.

To me, it sounds like your olive had some canola oil added. Canola oil has been reported to cause DOS.

I agree. Far more olive oil is sold than was harvested...

There can be a lot of reasons for DOS to develop, but I'll throw out another possibility based on my experience.

It could be the lavender EO you used. Robert Tisserand talks about lavender oxidizing much more quickly than most people realize. This oxidation can cause rare incidents of skin irritation in some people ... and it can also trigger DOS. The oxidation is not obvious -- I can't detect it by looking at or smelling the EO.

I made a 20% superfat high-coconut soap as one of my first few batches of soap. I divided the batch in half. I scented one half with peppermint EO and the other half with lavender EO. I poured each half into a log mold fitted with a temporary center divider and CPOP'ed the soap. Each half was treated identically except for the fragrance.

Both sets of bars eventually developed all-over DOS with the full-on rancid odor, but the lavender EO bars went "off" fast -- they looked unmistakably DOS'y within four months after they were made. The peppermint bars went bad about 4 months later (so 8 months old). I wasn't real happy about the experience, but I learned a valuable lesson about lavender EO. I now store my lavenders in the fridge and try to use them up promptly.

I learned a second lesson about the high superfat -- it's my opinion there was too much free fat in the soap. Don't care if it's coconut or something else. Too much is too much. I know that is heresy to some, but I really do think a low superfat, while it may not eliminate DOS, certainly reduces the risk.

Here are other triggers for DOS:

High humidity in storage and/or use

Exposure to sunlight or other sources of UV light

Anything that adds metallic contaminants, especially iron and copper, to the soap -- this could include air pollution, contaminants from the hands, or contaminants in the ingredients or the manufacturing process

Short shelf life or older oils that are oxidizing (not necessarily rancid, just oxidized)

Higher superfat so there are more free fatty acids and free fat in the finished soap

DeeAnna, I wondered about the lavender eo. Back in February I made an almost identical recipe, (difference was 3% more co, 5% difference between palm and lard) but used fo, and I'm absolutely positive that I used cheap olive. That soap has not developed dos, and it's been stored in a bathroom closet.

In fact, since I've started making soap back in February, only 1 other recipe developed dos (a basic palm/co/cheap oo recipe with peppermint eo)

The lavender eo's I used were brand new; a combo of 40/42, spike, and plain lavender.

Darn. Those bars were popular among my friends; wanted to make more for gifts.

Do you think using a combo of 50/50 combo of fo with lavender eo will help? Would using roe in the oils have any affect on the possible lavender oxidation?

DeeAnna said:

Here are other triggers for DOS:

High humidity in storage and/or use

Exposure to sunlight or other sources of UV light

Anything that adds metallic contaminants, especially iron and copper, to the soap -- this could include air pollution, contaminants from the hands, or contaminants in the ingredients or the manufacturing process

Short shelf life or older oils that are oxidizing (not necessarily rancid, just oxidized)

Higher superfat so there are more free fatty acids and free fat in the finished soap

Click to expand...

The shea and mango butters were four months old, not stored in fridge, also lids were not airtight. The oils were newer.

We have less humidity here in S. California than many places; and when the humidity is higher, those are usually air condition days.

Our water is r/o. Soaps cured in dark places.

I think the culprit is narrowed down to butters exposed to air, possibly cheap oo, and or use of lavender eo.

I had a similar issue with some of my recent bars. I usually make batches of 3 2lb logs. I used identical recipe for all 3 on the oils, and lye. Either milk, tea, or water on the liquid. One of the batches has tiny yellow spots. I smelled all of the oils and all smelled good. All oils were bought recently so I am thinking it's the green tea and ginger FO from BB. I bought a jug because I love the scent. I was wondering if I should contact them about it. The fragrance can't be that old. Purchased within the last year.

I just realized that I made another lavender eo soap about the same time as the dos batch. Very different recipe; no butters, heavier on soft oils as it for dandelion zebra swirl. No dos. Makes me lean toward the poorly stored butters as being the dos culprit.

Sounds like you're narrowing down the possibilities -- good detective work...!