SelSec

If you live in a humid place you're probably familiar with the effects of humidity on salt, sugar and some spices. Depending of the severity of the humidity and the duration of exposure, it can turn salt into wet mush and sugar into a brick.

SelSec is a bottle cap with an integral storage compartment for desiccant packages; specifically 10g silica gel in the white sachet. (Note that this thing is NOT for loose, unpackaged silica gel crystals!). The cap is designed to screw onto a spice bottle with 41mm outer diameter threads (Goya and Badia and other brands in plastic and glass bottles.)

SelSec is comprised of three pieces: the sleeve that screws onto the bottle, a platform that separates the silica gel sachet from bottle's contents and a snap-on lid to contain the gel pack. I printed the sleeve and platform on a raft.

Silica gel absorbs water and water weighs a lot (1g./cm⌃3). I wasn't sure what the weight of the silica gel packages I had laying around was, so I weighed one and it was 13 grams. I figured that sachet had already absorbed some water so I put it in the oven for 20 minutes at 300°F and reweighed it and it was 10g. I've seen instructions online that call for cooking it 2-4 hours! I suppose if you're refreshing a lot of packets, maybe you need that long? If you've got a digital scale you can figure out what works best for you.

Update: Added three "sifters" with different size holes. Sifter snaps onto the rim of the bottle.