Nope, not a typo. It vortex five gallons of wort.
That sounds incredible. I'm not able to open a ton of beer related sites on my work computer. I'll have to check it out later at home.
5 gallon starter. Sounds like my last brew.
For your batch size and gravity I reckon you should get something industrial or go the other route and get two 5L flasks and make a dual stir plate.
Getting a bar to stir on a carboy could be a hassle but I guess if the plate's designed to do that then there are no worries. Industrial's good.
