Relation Between Bitterness And Boil Strength

[JorgeGautier]

Hi, 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

 

[thegreatmaibockaddict]

Larger volume would mean lower gravity which equates to higher hop utilization which equals more bitterness.

I take it there was no rolling boil? What was the gravity at the start of boil? i would tend to lean on the lack of a sufficient boil, or the hops were not as fresh as you thought.

 

[JorgeGautier]

Larger volume would mean lower gravity which equates to higher hop utilization which equals more bitterness.

I take it there was no rolling boil? What was the gravity at the start of boil? i would tend to lean on the lack of a sufficient boil, or the hops were not as fresh as you thought.

I didn't knew that lower gravity equals higher hop utilization...
I didn't take a pre-boil gravity reading, but the OG was 1.050, wich was lower than I expected. And no, I didn't get a rolling boil at any time during the boil.

 

[KepowOb]

I'd say the lack of a good boil is your main culprit. The alpha acids in the hops will isomerize at lower temperatures than boiling, but you get diminishing returns as the temperature drops. Strange that you're getting a very low bitterness though, you should still get something out of them... I mean, some people get the bulk of their IBUs during the whirlpool afterall, and with a full "almost boil" it's strange that you'd get that little from such a high AA hop.

Perhaps there is an issue with your water as well?

 

[j1n]

What was the total IBUs for the recipe?

Id say your lack of bitterness and hop flavor is due to the lack of hops . you used 3.65oz of hops in the recipe which i assume is a 5 gal batch.

The last 3 batches i made were IPAs and the amount of hopes used was 7.5oz in the first one, 10oz 2nd, and 9oz in the last batch.

 

[JorgeGautier]

What was the total IBUs for the recipe?

Id say your lack of bitterness and hop flavor is due to the lack of hops . you used 3.65oz of hops in the recipe which i assume is a 5 gal batch.

The last 3 batches i made were IPAs and the amount of hopes used was 7.5oz in the first one, 10oz 2nd, and 9oz in the last batch.

BeerSmith calculated something between 80 - 85 if I remember correctly, but I can definitely get your point

 

[KepowOb]

I don't think the lack of hops would be an issue with an 18% AA hop... Brewer's Friend IBU calculator puts his hop schedule at over 100 IBUs (for a 5.5 gallon, 1.055 OG batch). Just the 1oz for 60 minutes gives over 60IBUs.

Another question... did you do a full boil, or top off with water afterwards to hit your target volume?

 

[solbes]

If its boiling, its boiling right? The temperature difference between a low boil and a high roiling boil is 0F. If you some altitude at your location, 2000 Ft or so, then the boiling point of water is around 208F. Also thermometers can easily be off by a degree or three at boiling temps if you haven't calibrated them before.

I can understand an IPA thats not bursting with aroma and flavor (2.15 oz in late additions/dry hop). But its not making much sense why its not bitter.

 

[JorgeGautier]

I don't think the lack of hops would be an issue with an 18% AA hop... Brewer's Friend IBU calculator puts his hop schedule at over 100 IBUs (for a 5.5 gallon, 1.055 OG batch). Just the 1oz for 60 minutes gives over 60IBUs.

Another question... did you do a full boil, or top off with water afterwards to hit your target volume?

Full boil