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can you really tell the diff b/w 5 IBUs? Diff b/w 1 and 1.3 oz hops?

Discussion in 'Homebrewing' started by GeeL, Mar 9, 2012.

  1. GeeL

    GeeL Aficionado (195) Massachusetts Aug 27, 2008

    Hi. As I'm playing with my new Beersmith, I noticed that many recipes have different IBUs than what BS indicates. I double checked the type of hop (pellet), %AA, etc. One recipe I just checked was off by 5 IBUs another by 7.

    I'm guessing with really hoppy beers, the difference is less noticeable, but what about lower IBU beers? I'm working on a recipe that says the IBU is 20, but BS says 15.

    Last, my LHBS uses 1 oz packets of pellets. If a recipe calls for 1.3 oz, is it worth buying the extra packet or just keep it at 1 oz? Hey, I guess I can use BS now to see what the difference is...
  2. cracker

    cracker Savant (405) Pennsylvania May 2, 2004

    Remember that IBU calculations are done via several different methods (Tinseth, Rager etc). The difference in number can come from there.

    Personally I don't pay too much attention to it to answer your question. Just use one formula consistently and stick with it for your IBU #s.
  3. If the recipe yor are targeting was formulated with Rager, then BS will be different as its default is Tinseth for the calculations. You can find the option in BS to change to Rager and run the same recipe and see what that predicts.

    The delta in IBU's that you can detect is often stated to be in the 4-8 IBU range IIRC. The lower threshold in beer is said to be in the 8-10 IBU, which is where Budweiser is said to be for IBUs.

    Yeah, you should be able to detect a difference between 15 and 20.
  4. thedude459

    thedude459 Aficionado (150) Massachusetts Mar 14, 2008 Verified

    And are you entering the actual AA in BS when you are making the recipes or are you going with the defaults that are there? I am sure you are changing them I just figured I would check.
  5. jbakajust1

    jbakajust1 Moderator (685) Oregon Aug 25, 2009 Staff Member Verified

    Beyond the IBU question lies another one... what addition is the 1.3 oz of hops for? Purely bittering, probably won't notice the difference. Flavor and Aroma additions the diff b/w 1 & 1.3 oz might be more noticeable, especially based on the malt bill and yeast.
  6. I read in a book somewhere, and I will try to go find it and cite my source, that you can not tell a difference in bitterness over 5 pts. Meaning that you could not separate a 25 IBU beer from a 20 IBU or a 30 IBU. However, I would think the lower the IBUs the easier it would be to tell, say 5 vs 10 IBU instead of 80 vs 85 IBU.
  7. inchrisin

    inchrisin Savant (480) Indiana Sep 25, 2008

    On a competition level, yes. For personal drinkability, doesn't really matter. Do what you're willing to dial in your recipe. I often just +/- 2 row to meet gravity and don't measure any hops with a pocket scale. Strike me down, Vikeman :)
  8. I can see the difference but not taste it.
  9. pweis909

    pweis909 Champion (750) Wisconsin Aug 13, 2005 Verified

    I've heard it said that 5 ibus is about the threshold of perception. So maybe some would notice and some wouldn't? i generally make recipes with even ounce additions, so I would either ignore the .3 ounces, perhaps trying to get bitterness by raising the boil time a little, or use the .3 ounces and see if I can distribute the remaining .7 as late additions to raise aroma. YMMV.
  10. With so many variables, IBU's really can't be calculated accurately simply by inputting the hop schedule into a piece of software. Even if the AA was absolutely known (the number on the label is likely not what's in the bag on brew day), the mere fact that multiple respected formulae give different answers is ample evidence of this. Close is close enough. 80 vs 85 is nothing to sweat over. RDWHAHB