Cleaning rendered tallow - what's gone wrong

[Sonya-m]

So I dry rendered some beef tallow in my crockpot a few days back but it smelt really meaty still so today I attempted to clean it using the water, salt and baking soda method (I'm sure baking soda is bicarbonate of soda?) and this is the result



This was it beforehand

 

[lionprincess00]

Maybe a little too much? Did you dissolve the soda into a little water first? Did you add salt, and how much. As it heats, there is a chemical reaction with the baking soda and the salt that produces carbon dioxide gasses. Did you see that happen?

Strain it.

Clean it again after it cools in the refrigerator completely. It needs to be rock hard before removing it.

That's left over baking soda, it seems. You can clean it a few more times and rid it completely, so don't fret too much.

 

[Obsidian]

Baking soda is a alkali and can saponify fat, I'd guess thats what happened. When I wash my fat, I just use water with a little salt. If you try rendering again, you might try the wet method. Its a bit messier but the chance of scorching your fat is lessened.

 

[DeeAnna]

It is possible that the baking soda reacted with some of the fatty acids or fats in your lard and made soap. Enough time and temperature, and even a weak alkali like baking soda can be talked into saponifying fats.

 

[lionprincess00]

Wow. Did NOT know that nor have had that happen.

Mine always reacts with the salts and in essence boils off. I get that scum looking (i guess soap) a little, but not nearly that much.

I just did what I read from different posters and the article here.

Maybe less baking soda for a first render, lower temps, more water and more salt than soda if you decide to use soda again. That way none is left free floating to create soap from.

Sorry Sonja. It should be fine to use still. Just strain it off.

 

[DeeAnna]

Most people don't know this.

It's not the way I'd choose to saponify, because it's slow and inefficient, but it definitely can happen. If one heats fat in the presence of water long enough, some of the fat will break down into fatty acids in a process called hydrolysis. This is especially true if the fats are older and are already beginning to hydrolyze on their own before rendering starts. Add an alkali, even a weak one like soda, and the fatty acids will happily do the saponification dance with the alkali. Voila, you get soap!

The reason why some people see this and some don't ... well, it boils down to time and temperature. Long time + higher temps + presence of water + presence of alkali => fatty acids => soap. Render as cool as possible, render with no water if possible, and render for as short a time as possible and still get the job done.

 

[Sonya-m]

I had a feeling I'd made soap - not a soap I'd want to try!!

I added the salt and bicarbonate to the water before adding my fat but didn't let it dissolve first.

Possibly used too much of both for the amount of fat I had

I did strain it when I poured into there but have done it again. I'm probably gonna be left with 100g of tallow after this!!

Oh well, I've been to the butchers today and they're gonna save me all of this weeks beef fat cuttings and are going to mince it for me too - all free of charge. So will try again next weekend.

 

[Sonya-m]

Lionprincess do you do yours in a crockpot or in a pan on the hob?

 

[The Efficacious Gentleman]

I think that minced will help with the first rendering. Less chunks left over and more fat in liquid form

 

[DeeAnna]

The soda has reacted with your tallow to make flecks of nice tallow soap, although the superfat is a bit higher than I'd like. The other end product of carbonate saponfication is carbon dioxide gas (CO2) -- that's the fizziness that LionPrincess is seeing.

 

[RogueRose]

I once cleaned bacon grease that has lots of small burnt meat pieces in it with boiling water and salt. I also tried a pressure cooker and it worked very well. I was doing about 5lbs of lard.

If using the water method there are some things you MUST be careful about. The grease can super heat and if stired into the boiling water it can create an instantaneous over-boil and possibly cause a fire or at least a major mess, I know... What happens is the water never gets above 212 degrees but the steam gets hotter and the grease I'm guessing can get above the 212 as it is on top of the water (steam heated). When stirred into the water, the grease transfers the heat completely and immediately to the water causing instantanious over-boil which is very dangerous.

Another thing to be careful of is the grease forming a solid layer on top of the water, blocking the steam (maybe absorbing steam/heat??) and then sometimes there is sudden movement where the oil is mixed with the water and instantaneous over-boil. This is a little more confusing, but kind of same principle as above.

Things to know:
-Use the largest pot you have (well within sense). I would suggest filling no more than 1/3 full with water/grease if possible. If using just grease, this isn't as important.
-The more water you add to the grease the better cleaning job it will do.

When done boiling allow to cool (place outside if cool outdoors & cover - animals will be attracted).

Drain off excess dirty water, leave about 1:4 water:grease remaining in pot. heat on low heat to melt. Pour in disposable plastic bottle such as soda bottle and store upside down in cool place. This will allow you to remove cap and drain water - cut open bottle and scrape of bottom layer of lard which will be a little dirty.