DOS Query

As a ginger haired canvas for a million freckles, perhaps I am a little sensitive to everyone's tendency to be intolerant of the Dreaded Orange Spots.

So, I must ask. Do the DOS's have any effect on the efficacy of the soap, or is this simple snobbery of the lowest order against those of us that are speckled?

 

Seriously? I can't tell if this is a joke or not. DOS is spots of rancidity, while the soap is safe to use it will eventually get oily and develop a terrible smell.
If someone sells, having soap that gets DOS easily can be bad business. You want your products to be fresh and long lasting.

 

So, if I render my deer trimmings fresh, store the rendered tallow in the freezer, then make soap from tallow that is NOT rancid...I am not going to end up with DOS, right? The references I am seeing for DOS are confusing to me.

And yes, while I may pose my questions in a wry or quirky manner, I am seriously looking to learn a little something here.

 

Unfortunately its not always that easy. Using fresh oils will definitely help but there are many variables that can cause DOS.

Anything from contaminates in the water, to curing on metal racks to the way its stored.

This is why its important to keep at least one soap from new batches and see how it ages.

I recently had a batch get spots, I have no idea why and its frustrating as heck.

 

As a ginge with no freckles ( just dreadfully pale skin) I can't empathise, but I can say that thankfully I have avoided DOS, albeit still very early in my soaping journey. One way you can *help* avoid DOS is by keeping your linoleic and linolenic acids (combined) under 14. But that's not necessarily the only way. Other soaperts will probably have more advice.

 

Snobbery!

You are reducing your chances of getting DOS by limiting the time the fat is exposed to the meat, after the animal has deceased - the iron in the blood can potentially trigger DOS, so rapid cleaning is good. Freezing is also good (in my book), not so much for the fat but for any water based liquids that might be left in the fat - these can trigger rancidity and DOS too.

So ... trimming quickly, rendering until the fat is "dry" (no spitting), rendering at a low temperature (this is important too - you want to limit the time the fat is on high heat) and freezing the fat for storage will all help.

Don't use rusty tools, don't let it come anywhere near anything bronze, copper (or any copper alloy) and keep everything as clean as possible. Some people do a wash with salt or bicarb in the water - if you do that, do a plain water wash and get the water out of your fat before you store it (the old fashioned way was to cook a potato in it - when the fat doesn't sizzle and the potato is done, the fat is "dry" and ready for storage/soapmaking).

DOS is fat rancidity, so avoiding anything that will trigger that is what you want - keep the fat out of the sunlight, keep it clean, away from metal, don't overheat it and freeze the fat if you are keeping it for a while.

 

Even better - add ROE to the freshly rendered fat so the ROE can protect the fat during storage.

 

For my learning - can DOS develop in any oil combination, or only those that include an animal based fat? Thank you!

 

Sometimes exposure to heat/light can encourage DOS as well. This summer I did an outdoor show (in extreme heat) and one of my tables was in the sun for 6 hours of the 7 hour show. A week later I noticed that many of my soaps had DOS. As I was pulling them out of stock, I realized that all of those soaps had been on that table in the sun. There were some bars of the batch that didn't have DOS at all, so I suspect that those bars were the ones that were not on the table and had been left in storage under the table (and out of the sun). None of the soaps on the shaded table had DOS - and I use mostly the same recipe for all my soaps, just changing up additives.

Side note: my new tent for this coming summer has side walls to help provide shade, just in case you were worried about me

 

Any oil combination, but some fats and oils are more prone to becoming rancid than others.
The short chain, unsaturated fatty acids, linoleic and linolenic, are quite short lived and susceptible to DOS if used in high quantities in soap, especially when the superfat is also high.
Fats like safflower, grapeseed oil and hemp are examples of some short-lived oils (as wonderful as they are on skin and in soap, these oils need looking after - refrigerating etc.).

 

Thanks Fellow Member of the Not So Secret Ginger Society (NSSGS)! I intend to stay with making the deer tallow base soaps for the foreseeable future, since I am not into soaping for soaping sake, but because it is a useful skill and a way to make a more efficient use of the animals I harvest. Can you point me in the direction of some good reading on lineleic and linolenic acids in deer tallow? I think I am also going to look up the history of linoleum since I am now curious about the source of that word and how it might be linked with the aforementioned acids.

Thanks everyone for being so wonderfully tolerant of me and my questions!

 

SoapMakingFriend (the SMF recipe builder/lye calculator) has the following listed for Deer Tallow:

Tallow Deer
Lauric 0
Myristic 1
Palmitic 20
Stearic 24
Ricinoleic 0
Oleic 30
Linoleic 15
Linolenic 3

From: https://www.soapmakingfriend.com/soap-making-recipe-builder-lye-calculator/

 

So it looks like this would have a score of 18 when adding the Linoleic and Linolenic levels.

I put a bar to the test washing my hands this morning. Virtually NO suds. I am thinking the last soap I did had some OO added just for that purpose.

 

Yes but combined with your other ingredients that may change the score.

 

The recipe is at the top of my thread "Tallow Ho!" But here it is for convenience:
1175 grams pure deer tallow
152 grams Rooto brand sodium hydroxide drain cleaner
540 grams water

 

I have a potential source for deer suet for next season, so I am going to follow your deer tallow adventures!

A good base is:

40-50% - lard, tallow or palm (I think deer tallow would go here.)
10-20% - coconut - gives fluffy bubbles but can also be harsh/stripping
5% castor (10% is too much, IMO - this helps with lather)
Remainder in olive, HO sunflower, rice bran or HO safflower (or a combination).