I have about 20 of them and use them for apfelwein. I've always used them for still apfelwein and used bombers to carb half the batch in. I've always wondered if they would hold pressure but hadn't had the gusto to throw some carb tabs into one to test it. I have a flawless bottle bomb record and I'm not about to break that with an experiment.
Cellar Door Brewery
Primary: Smoked Porter
Secondary: Flanders Red 2010
Kegged: 10.10.10, Robust Porter, American IPA
"Without algae, there would be no life on earth, the seas would be sterile and the land would be uncolonized."
-Sir David Attenborough