Canning Jar Fermentation Lid
by AlexEnglish, published
This lid uses water to form an air trap that will let carbon dioxide and other gasses vent off of fermenting foods, while keeping out the oxygen that would spoil them.
Some ideas for fermented foods this could be used for include sauerkraut, kimchi, ginger beer, or pickled vegetables (garlic, carrots, peppers, etc). Fermented foods are healthy, easy to prepare, and taste delicious.
This was inspired by this: http://www.pickl-it.com/ and motivated by this: http://www.thingiverse.com/thing:4663 and my completion of a general purpose canning jar lid (here: http://www.thingiverse.com/thing:19105).
The air trap is one piece, with no moving or meshing parts.
This thing is a part of a collection of things featured in this post: http://www.protoparadigm.com/blog/2012/08/what-to-do-with-a-3d-printer-make-canning-jar-accessories/
This is a work in progress. At present, the air trap mechanism seems to work just fine, but the lid itself doesn't seal well enough to provide a barrier to gas. A gasket (a jar rubber or something) probably needs to be incorporated to keep the whole thing sealed. Parafin dripped around where this part and the jar make contact may do the trick.
To print, you'll need to make sure it is as air-proof as possible. I'd recommend 100% infill. Make sure your bridging works reasonably well, and that your layers and traces flow together well.
To use it, just put it on your jar, and fill the reservoir on top about half full of water. If you under-fill it, it won't do anything, and if you over-fill it you'll get water leaking down into your jar (though this shouldn't hurt the food, so it probably wouldn't be much of a problem).
For some recipes for fermented foods, check out http://www.pickl-it.com/blog/recipes/ . Some of the recipes are a bit out there, but some of them are pretty standard, tasty fare. There are many other places to find recipes to find recipes too; I picked this one because the recipes are targeted towards small (canning jar sized) batches.