Will it keep in this jar?

Yes, I've had some for 10 years and it's still good.

Might be a good idea to put a small dessicant packet in the jar for long term protection.

It better be really, really, really dry - if not it could mold.

Appreciate the tip Mr. Jameson.

Desiccant is made to absorb moisture. When it sits around, it has already absorbed any and all the moisture it is going to. It does not know if it is in a jar of caster or sitting on the table. Unless you have desiccant that can be dried, you can be adding moisture to what ever you put it in.

Dried castor never spoils, I still have some in a bag from the 70s

The primary key to long term storage is to be sure the powder is in fact dry as stated. There are many variables and assumptions when doing these things. If you havent got a good handle on it yet you will learn some things down the road.

We put up gallons of dried castor annually and I learned you must protect your investment. Or it could be a bitter dissapointment a few years down the road when it is time to use what you thought was prime No. 1 material.

Some dessicant packs can be heated and reconstituted in an oven to near new dry condition. Like stated they are a silica product and will constantly draw moisture from the environment if left in the open air. We buy many bulk dessicant packages yearly to place in "moisture drawing" materials that have been broken down into smaller workable containers and stored until use.

Ebay and Amazon have them listed in different sizes.

In a pinch I have use torn pieces of those blue paper shop towels and mixed them thru the castor to help gather the moisture. Works ok. A folded piece in the bottom in the middle and on top of the material will do nicely if the material isnt too wet.

It is a good idea to shake your containers periodically. If they seem to cake in some areas you know you have some moisture in it.

Our castor is ground small, dried and then blended in a good blender to powder it. Your batch seems to have some larger pieces of skin. These pieces can hold moisture. The smaller the grid size the better and faster it will dry.

Thank you Mr. Jameson, I'll keep an eye on it.

Vaccuum pack it and freeze??

See stores selling castor pods guaranteed to be at 10% moisture or less, anyone know how they are testing complete pods for moisture content?