Vinegar cleaning - what is it doing?

[Stig]

My new ss 26gallon is up and running. I wiped it out then added about 5 gallons of water and 3.5 of vinegar, heated it up till steaming, let it run for 20 min.
I had thought my garage would smell like pickles but really didnt smell much. I thought the vinegar was mixing with the steam and cleaning all parts of the pot and head? So i looked up the boil point of vinegar and google says 244 F which i of course did not reach.
So what exactly is going on? Is the steam taking some of the vinegar up and cleaning? or is just the steam doing the cleaning?