I really enjoyed the book “Modern Lager Beer”. It made me refocus my Decoction temperatures and times and step outside some of the specs yeast manufacturers have on their products. I decided to follow the recipe for Weihenstephan Helles and in creating the recipe in Brewfather I was able to hit every number dead on. The FG the software gave me does not reflect a fermentation temperature of 10 degrees but I am pretty sure the attenuation will decrease at the lower temp. The problem I have is I simply cannot make the IBU’s match with the amounts they provide. Even if I can get the AA to match the amounts are off by around 20 g. If anyone has brewed this, have you had this experience or is it simply three typos for the hops?
Possibly they’re using a different hop utilization formula than your software. I know Brewing Classic Styles uses the Rager formula because it was (is?) popular with extract brewers. It calculates hop utilization differently than Tinseth or Garetz and could be the reason that some people say BCS recipes don’t work for them because the recipes are written for extract.
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I use the Tinseth formula because it gives me more accurate results for all grain recipes. Dwain is right about Rager being used by extract brewers.
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The book says assume T90 hops so I did. While I have used the Tinseth model for hundreds of brews, I do find it more suitable for whole hops but continue to use it for most hops. My boil time is always an hour or more which actually makes Rager more predictable with T90 pellets. I can mess around with the utilization model all day and change the hop type from whole to pellets. I plug the numbers into Beersmith or Brewfather and the results are still very low. I will try to contact the authors but I have a feeling there was a transcription or publishing error. They got the recipe from Weihenstephan in SI units then translated to the US system. A few spots for transcription errors. if I double each amount and keep AA and boil times the same the IBU is dead on.
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Hop utilization is always a model estimate derived from data that didn’t come from your system and the way you brew. In reality, you need to calibrate your senses to get a handle on what different IBUs taste like even if the only measure of IBU is what your software model says. I recommend brewing the recipe once as written and take tasting notes when its done and on-tap. Then you’ll begin having an association between whatever IBU estimate your software gives and what you taste.
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Especially check out the mIBU discussion.
That is usually how I do it. The issue is the hop amounts as written do not get to the values stated. The recipe says it will be 25 IBU. The hop loads and amounts only come to 11 - 14 regardless of which utilization model I use. I have brewed 1273 times over 38 years and the times I use a recipe the numbers are all pretty close. I will wait to hear from the authors but in the meantime I will brew with double the hop amounts to get to 25 IBU.
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Sounds like it’s a typo then if the volumes are the same and you’ve done what you’ve said. Your plan seems what I would do as well. Happy brewing!
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