What is the purpose of the 6.5 gallon threaded carboys?

[hector219]

I just realized that my 6.5 gallon glass carboy has threads and a smaller lip than the standard carboys. I bought it a few years ago and never really noticed the difference. I'm wondering if anyone knows what the threads are for.


- Adam

 

[MaxStout]

They used to be used for shipping acids, and are sometimes referred to as "acid carboys." I think there was a screw cap on those when they were used for that.

 

[beerstache]

My 6.5 carboy came with a plastic screw cap which I use to hold in cleaning liquids that I swirl around. glad I kept the cap, as my lhbs will throw them out if you dont want them.