How to remove the odour of frying doughnuts from oil

[Ladka]

I used almost one litre of high-oleic sunflower oil for frying shrovetide doughnuts last Sunday. I'd like to reuse the remaining oil for soap. I strained it when it cooled down to remove any bits and am now thinking of how to remove the odour. Also, as the dough was sweetened I'm at a loss as to what to do with any sugar remaining in oil.
Any advice will be appreciated.

 

[DeeAnna]

Sugar isn't soluble in oil. If you have strained it well, any small bits of sugar should be gone. But even if there was a little bit of sugar left, I would think it would be fine in soap. After all, people do add sugar to soap for lather.

To remove the odor, you can wash the oil with water, just like people wash lard or tallow to remove odor.

LionPrincess shared a nice tutorial of how she does it. It's been a few years back. Perhaps you can do a search on LionPrincess's name to find that post?

 

[Ladka]

Thank you @DeeAnna! I render all my beef tallow and lard and am quite familar with the procedure. But I've never applied the procedure to liquid oils so am rather uncertain, especially so at the point where oil is separated from the unclean water with salt.

 

[Megan]

I don't know if this will help but I imagine it's like when you try to de-fat a chicken stock for example, you decant the oil from the top of the water phase... I wonder, if you could try freezing? The water should freeze and the sunflower oil should still be liquid.
Edited to add, I don't know how this works with the salt water component, if the water is saturated or how much salt is added.

 

[DeeAnna]

After standing for some time to let the oil and water layers separate, I skim the oil off the top of the water. I suppose you could freeze the whole thing as Megan suggested, but I haven't ever done that.

 

[Ladka]

Thank you so much, @Megan! I did one washing with salted water (used a copious amount of salt) and tried to decant. And here is my problem: I can't see when water starts flowing together with oil. I will now use very little salt and then freeze. Cause some odour still remains

 

[DeeAnna]

"...I can't see when water starts flowing together with oil ..."

I use a clear container so I can see the interface between the water and oil layers. If I pour the fat off (decant), I stop decanting before any water wants to come with the oil layer. Then I switch to a ladle to remove the last part. I don't try to remove every last drop of fat, because the interface between the fat and water is likely to have some impurities I don't want in the fat.

Oh, forgot to add -- If there's a small amount of water that does end up in the oil, you can heat the oil to drive off the water. When the oil stops popping and crackling, the water is gone.

 

[Ladka]

Thank you everybody for your advice! I froze one cup of salted water+oil and enjoyed at how easily the oil, nicely thickened, could be removed from the top of ice.

 

[Megan]

Nice! Glad it worked out for you!

 

[ResolvableOwl]

the oil, nicely thickened

High-oleic oils (HO sunflower, olive, etc.) have a surprisingly high melting point.