Warded Jar

Warded Jars are items that are capable of storing essentia. They are needed in the crafting of Alembics, as well as of Brain in a Jar; each jar can store up to 64 of one given Aspect.

Thaumonomicon Entry
"You have discovered a way to craft mystical containers reinforced with magic. These warded jars can keep almost anything contained within them - even things that cannot normally be contained. Warded jars are also capable of storing essentia and can be filled from essentia phials. They also act as an essentia source for Infusion Altars. If you have some automated way of gathering Essentia, you can mark the jars in the usual manner to have them automatically refilled.

What is more, they make an excellent storage medium for jams and preserves."

Crafting
Warded jars are crafted on an Arcane Worktable or an Infusion Altar, with 7 Glass Panes and 1 Arcane Wood Block, at the cost of 20 Vis.