During my preparations for #BeeryLongReads2018, I found more information regarding my historic Vienna lager. In particular, I found more information about one topic that has been quite difficult to find anything out about: hopping rates. I blogged about the hops used in Vienna lager previously.
In the book “Die Theorie und Praxis der Malzbereitung und Bierfabrikation“, published by Julius Thausing in 1888 (previous, less comprehensive editions, e.g. from 1877, are available), the author lists typical hopping rates for Vienna lager beers. The amount of hops varied depending on the original gravity:
- 10.5%: 1.8 – 2.2 – 2.5 g/l
- 11.5%: 2.5 – 2.8 – 3.0 g/l
- 12.5%: 3.0 – 3.3 – 3.6 g/l
- 13.5%: 3.3 – 3.6 – 3.8 g/l
- 14.5%: 3.6 – 3.8 – 4.0 g/l
- 15.5%: 4.0 – 5.0 – 6.0 g/l
Low-gravity beer was generally brewed with an OG of about 10% and sold after 6 to 8 weeks, while the regular Lagerbier was brewed with 13% OG and lagered for 4 to 8, sometimes even 10 months or more. This hopping rate is a bit lower than what I had found in other sources before, which prescribed a hopping rate of 4 g/l for Vienna lager.
Of course, with the absence of any information regarding alpha acid, the actual bitterness still remains a big miracle.
In the years 2006 to 2015, the alpha acid content of Saazer hops varied between 2.1% (2015) and 4.0% (2011); the average 3.15%, the median 2.9%. At a hopping rate of 3.6 g/l in a 13°P wort and 90 minute boil time, this can mean a bitterness between 19 IBU and 37 IBU! Most likely, the answer lies somewhere in-between, so for hops with 3.15% alpha acid, this would mean 29 IBU, which seems absolutely reasonable and is close enough to some of my previous estimations of 27 IBU. I take this as a confirmation that a hopping rate to achieve a bitterness of around 27 IBU to 30 IBU seems appropriate for Vienna lager, at least from a historical point of view.