I've made my own kraut and Kim chi quite a few times. I bought a
German crock that has a moat for a rim; you fill the rim with water and the lid sets down in the water filled moat. This makes for an airtight seal, but the fermenting product inside can burp when/if it needs to. It's designed specifically for kraut.
My next fermentable I'm just going to try my hand at soon.......KOMBUCHA!! Man is that stuff tasty and refreshing. Fermented tea. Think sparkling cider or tangy ginger ale and you've got an idea of its flavor. Tart, just the right amount of sweet and fizzy. And it has naturally occurring alcohol normally between .5-1.5%.
I just ordered some gallon glass jars last night for my Kombucha project.
Chris L