Making gelatin from scratch

Question

I found on Wikipedia that it is made from animals' skin and bones. The article describes the steps of gelatin production from a technical perspective:

The manufacturing processes of gelatin consists of three main stages:

1. Pretreatments to make the raw materials ready for the main extraction step and to remove impurities which may have negative effects on physiochemical properties of the final gelatin product,
2. The main extraction step, which is usually done with hot water or dilute acid solutions as a multi-stage extraction to hydrolyze collagen into gelatin, and finally,
3. The refining and recovering treatments including filtration, clarification, evaporation, sterilization, drying, rutting, grinding, and sifting to remove the water from the gelatin solution, to blend the gelatin extracted, and to obtain dried, blended and ground final product.

How can you make gelatin from scratch in your own kitchen?

Answer 1

It's the refinement that's the real issue: anyone who's braised a big joint of meat knows that a couple of hours of low-temperature stewing will net you large amounts of gelatin. Hooves and antlers were the preferred media, but anything that's got a bunch of collagen will work. Talk to your butchers shop, and see if you can buy some bones.

Refinement was done the old fashioned way: by hand. You skim the top to remove the scum, you add egg whites to degrease and to clarify the "broth", and then you strain and strain and strain and strain.

And strain. And strain. And strain. The skimming/straining process is similar to rendering sugar from sugar cane, if you've ever done it (slightly less esoteric, because people still like molasses). They obviously don't use egg whites in rendering sugar.

It's a huge amount of work (and OMG it stinks...do it outdoors if possible), and the end result is probably not going to be on par with the stuff you buy from the store. Unless you're hankering to re-invent an ancient technology just for the fun of it, I'd just buy it.

Edit: I dug around, and there are a number of products for straining jelly that might make it easier, and they should be able to deal with the viscosity of the gelatin soup. Unfortunately they seem to be made for smaller batches, and that may not be helpful if you're doing a huge kettle.

Answer 2

That sounds as though they are speaking about how gelatin is made for making commercial, powdered gelatin. I actually have a "recipe" method in an old cookbook from the early 1920's that tells how to do it. Unfortunately, I am not at home, so I will have to post it later tonight. It was very interesting to read, but I got a little grossed out when I read one of the steps. It actually said, "Remove the scum."