Last month I made an IPA with some experimental grapefruit hops with 18% AA but the final product turned out with very low bitterness and low hopppy flavor.

The first thing in my head was that it could be because of the weak boil I had the day I brew it due to technical difficulties (208 F was my average boil temp.). The other thing a suspect could have messed with my bitterness is a larger than required pre-boil wort volume.

My hop schedule was: 1 oz @60 min 0.5 oz @30 min 0.5 oz @10 min 0.5 oz @5 min 0.5 oz @flame out 0.65 oz Dry Hop

  • What yeast did you use? Yeast in suspension can sometimes mask hop flavor, until it drops out. How old is the beer right now.
    – GHP
    Commented Jun 26, 2014 at 17:22
  • I used White Labs 001 with starter. The beer is now 3 weeks old. Commented Jun 26, 2014 at 18:03
  • 001 sometimes takes time to floc out, how clear is the beer?
    – GHP
    Commented Jun 26, 2014 at 18:39
  • Beer turned pretty clear. I leave it two weeks in primary a another week in secondary dry-hopping Commented Jun 26, 2014 at 18:51
  • I asked almost the same question in February Commented Jun 27, 2014 at 14:12

1 Answer 1


A difference of a few degrees (208 vs 212) is not very significant from an isomerization perspective. Studies have shown that isomerization continues to occur in whirlpools at or below 200 degrees.

Things that could have affected utilization:

  • Wort strength - higher gravities will lower utilization
  • You mentioned extra pre-boil volume - as long as you hit post-boil numbers from your recipe that shouldn't affect anything, but having extra post-boil volume would cause lower bitterness and gravity than the recipe indicates
  • The hops could have been mislabeled - were they from a reputable supplier?

What are you comparing the beer to to determine that bitterness and hop flavor are low? Those hop amounts are lower than I would normally use in an IPA where I was shooting for excessive hop character.

  • Thanks for the info. I was trying to compared it to any average IPA.. Maybe Stone's IPA.. but from what I can taste this is less hoppy than typical a pale ale.. I used a total of 3.6 oz of these hops, I guessed that from their high Alpha Acid percent this will be enough to make a pretty hoppy beer Commented Jun 26, 2014 at 18:23
  • Why do you think the extra volume (if boiled off) would cause less bitterness? I would have said it would cause more - hop bitterness is mostly a function of the amount of solids that the alpha acids can bind to before dissolving in the wort. A more diluted wort has fewer solids per unit area, which makes hop utilization slightly better.
    – mdma
    Commented Jun 26, 2014 at 20:51
  • I just thought that the hops will dilute more causing the hops to back down... Commented Jun 26, 2014 at 21:04
  • I see now you said extra post-boil, so that makes sense. +1
    – mdma
    Commented Jun 27, 2014 at 13:58
  • "Studies have shown that isomerization continues to occur in whirlpools at or below 200 degrees" - What studies? Do you have any links? I was under the impression that isomerization quickly drops off under 212. Commented Jun 27, 2014 at 14:08

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