This is a question that has been brought up through the ‘ask JK’ emails a few times and after looking online there‘s a lot of debate about the most effective temperature for whirlpool hopping. The theory behind whirlpool hopping at 80°C is that delicate hop essences are less likely to be driven off and there will be a higher proportion in the wort, meaning greater hop aroma and flavour. I’ve personally never done it this way preferring to utilize the alpha acids contained within the hops to provide a smoother bitterness while at the same time providing aroma and flavour to the beer. I’ve always stuck with this as it means that I get a pleasant bitterness, use less bittering hops and suffer less wort losses.
I decided we needed a definitive answer to this so I decided to split batch a New Zealand Pilsner and whirlpool hop it at 100°C and at 80°C;
95.2% Pilsner Malt
4.8% Acidulated Malt
10g Herkules @ 60 minutes
Theoretical Ibu: 43.7
I split this batch down after boiling into two 10 litre batches and began chilling one down to 80°C. I whirlpool hopped the batch that was still at 100°C with 80g of Motueka for 30 mins and when the second half of the batch reached 80°C I whirlpool hopped that with 80g of Motueka for 30 mins.
This was fermented for 14 days at 12°C, bottled and then lagered for four weeks at 1°C
To determine what effect whirlpool hopping at two different temperatures has on the overall hop character of the beer I conducted a blind triangle tasting focusing on:
- Overall Preference
With regards to impact: 100% of the tasters correctly identified the ‘different’ sample with regards to flavour, aroma and bitterness.
FLAVOUR: 100% of the tasters choose the 100°C whirlpooling sample stating it had superior hop flavour.
AROMA: 100% of the tasters choose the 100°C whirlpooling sample to be aromatically superior.
PREFERENCE: Overall preference was split but comments collected showed that those who preferred the 80°C sample liked the mellow bitterness and weren’t fans of high IBU beers i.e. they preferred it as it had less bitterness – wierdo’s! 😉
I tested the bitterness of both samples by running them through the Spectrophotometer at work; results as follows:
IBU 100°C whirlpooling: 45.5
IBU 80°C Whirlpooling: 30.8
An interesting experiment with fairly conclusive results – does this confirm or go against your whirlpooling hops experiences?