The BYO recipe is on the low side with respect to IBUs for the style, but it still higher than that of DB Vienna Lager, which is at the absolute bottom of the IBU rating for the style. For me, I personally think that Vienna tastes less sickly sweet when 90 to 100% Vienna malt is used and the hopping rate is closer to 30 IBUs, which is at the top of the range. Surprisingly, I used to drink Dreher beer when I lived in Italy. By that point in time, Dreher was owned by Heineken, but it was definitely a different beer than Heineken. I had no idea as the history of Dreher. It was just the local brew.