Hej Ref
Have to admit, I’m a little skeptical about this- I kinda question whether they would have been willing to sacrifice so much fuel just to boil away the water- it’s the same issue as with their making salt from sea water… I’d be more inclined to see them using malted barley flour, or actual wort -probably before adding gruit, but possibly after, depending on the gruit recipe they’d use and/or what they were adding it to…