Yes - Carefully.
You don't have as much room for boil overs, but yes you can do a half bbl batch because the total volume of these pots is pushing 23 gals. Just keep an eye on things and you should be fine!
Oh - and for many of you, your next question is "are you guys going to do a 30 gal BME?" We are going to see how things go with the 10's and 20's relative to market demand. The dished bottom tooling costs a fortune to make - so we are going to step into that next size carefully and when the time is "right".