AHA Hop Stand Experiment

A very interesting article here on the American Homebrewers Association website about the bittering and flavour potential of different forms of hop stand:

The Effect of Post-Boil/Whirlpool Hop Additions on Bitterness in Beer

Personally I have previously not bothered to consider the potential bitterness increase from flame out additions because I either chilled to 80c first or chilled all the way to pitch temp straight after adding hops. I am now questioning both of these based on some of the results in this experiment, that said however it is important to qualify first of all how the experiment was done and the situations in which its findings are most relevant. The tests used a 1 gallon batch with 28g of 14.9AA% El Dorado hops added at different times/temperatures, this would be equivalent to just over 140g for a hop stand in a 23L batch. Even the most hop obsessed brewers would consider that fairly hefty for a single addition, the high alpha acids % of the hops used is also significant as the effect on bitterness will be magnified which was clearly the intention of the experiment but might make the results appear more eye popping than they actually are!

Anyway in light of that I would say that if you are using modest sized additions and/or low AA% hops then this isn’t really anything to worry about and any impact on bitterness will be negligible however the information on flavour extraction may be worth considering.

On the other hand if you are using large additions and high AA hops (APAs, IPAs, DIPAs are most likely to be affected) then it might well be worth factoring in the potential bitterness increase. An IPA I recently did had a large flame out addition of Vic Secret hops which at 15.5%AA will have had a significant impact that I didn’t account for (I thought that brew was a bit more bitter than expected!).

The other key points to be drawn from the article seem to be:

• Bitterness will still be extracted as low as 80c, in fact utilisation was only fractionally lower than wort that was just below boiling.
• The impact on flavour and aroma seemed to have no significance in the sensory tests (more on this later*).
• Even with immediate chilling some bitterness will be extracted (in as little as 90 seconds potentially!)
• Longer steeps will increase the bitterness extracted but perhaps not in the linear way predicted by some calculators/software
• Shorter steeps (10mins) might be better for flavour/aroma

*The second point is also corroborated by one of the Brulosophy experiments where there was no apparent difference between a hot hop stand and a cooled hop stand.

In terms of my own brewing I already had my doubts about chilling prior to flame out after reading the Brulosophy experiment and after seeing this will no longer use this method. It appears that it is basically a waste of time as it does not produce discernible differences in flavour aroma or bitterness.