Ask Mr. Wizard

Late Hop Additions


Mark Windmill asks,

I made the mistake of adding post-boil hops to the kettle at 104 °F (40 °C). I think that I should have added the hops at 176 °F (80 °C) after flame out. Will adding hops at 104 °F (40 °C) spoil the beer?


wizard webThe one very important thing that all brewers should know about hops is that they are not a source of beer spoilage organisms when added to normal beer. My definition of normal beer means that the beer contains at least 3% alcohol by volume and some hops to add bitterness. Normal beer is prone to spoilage by certain organisms generally called “beer spoilers,” including Lactobacillus and Pediococcus bacteria (both lumped together as lactic acid bacteria) and wild yeasts like Brettanomyces. But normal beer is not a good growth medium for the microflora that is found on hops. In practical terms this means that brewers can feel free to add hops to wort or beer at any stage of the process used to produce normal beer without having to worry about introducing beer spoilers.

This does not mean that brewers simply add hops without any real plan. If you want to impart bitterness to your beer it is important to add hops to wort and boil for at least 45 minutes. During the boil, alpha acids present in hops dissolve into wort and isomerize into the much more soluble and bitter iso-alpha-acids. Hops added later in the boil are usually added for their aroma contribution because the shorter boil time limits isomerization, yet the heat of the wort does extract hop aromatics. There is also some aroma removal when hops are added to hot wort and many of the “high notes” that you smell when hops are added to the kettle are lost to the environment. This is why brewers wanting those pungent and fresh hoppy notes add hops after the boil either to their hot wort or to their beer as “dry hops.”

It sounds to me that your recipe called for some late kettle hops that were intended to impart some of these high notes, but maybe not as much of the hop high note as one would get from dry hopping. Or perhaps the person who wrote the recipe did not like messing around with dry hopping and formulated their recipe so that all of the hops would be added on the brew day. I do not think that adding hops to 104 °F (40 °C) wort will do anything to this beer that you can detect upon tasting, unless you brewed a few batches of the same beer with the only change being the time of your last hop addition. Even in the event of this unlikely example, I bet that the differences between the brews would be minimal.


Response by Ashton Lewis.