Hop Creep Revisited
TroubleShooting
Greg Stoner — Elizabethtown, Pennsylvania asks,
I was reading the Mr. Wizard answer titled “Hop Creep Explained” and have had the issue of overcarbonation with a couple IPA batches that I dry hopped. I thought that I had made a mistake with the priming sugar, but after reading that article, I believe hop creep was the problem. Would it make any sense to adjust the amount of priming sugar to compensate for the hop creep? I did a little more research and read about lowering the wort pH in order to compensate for hop creep. Do you have any suggestions on how to measure and adjust pH to compensate for hop creep?
I rarely answer similar questions in a single column, but this question pairs well with Greg Hutchinson’s question in this issue about over-carbonation and is a good follow-up to my “Hop Creep Explained” answer from January-February 2019 issue. This is kind of like beer and food pairing, but it is rather a topical pairing!
OK, so you are thinking about adjusting your priming dose for beers that have been dry-hopped. There are several challenges with this proposition. The first is that not all hops have the enzymes that cause hop creep. Research into this phenomenon is limited and there seems to be little known about what hops contain active, debranching enzymes that lead to the production of fermentable sugars from dextrins. If you don’t know whether your hops contain debranching enzymes, you cannot adjust priming rates because not all hops contribute these enzymes to beer. And even if you knew that your hops did contain debranching enzymes, you cannot determine how much carbon dioxide will be added to beer as a result of the enzymes without running a trial test, and then using this information to determine how much priming sugar is needed to achieve your target carbonation level.
Although enzymatic rates are influenced by pH, it is not practical to change the pH of the wort/beer system enough to prevent the activity of this enzyme group without causing major changes to overall flavor and character of the beer.
In practice, you need to allow sufficient time after dry hopping for any enzymes from the hops to do their thing and for the yeast in the fermenter to metabolize any boost in fermentable sugars that may come late in fermentation. How do you know that things are complete? This is where your handy hydrometer comes to use; monitor your beer gravity and consider fermentation complete when the gravity is stable for about 5–7 days after dry hopping. This does not mean that you must keep beer in contact with hops for 5–7 days, it just means that you need to keep your beer at fermentation temperature with yeast for long enough to confirm final gravity has been achieved. If you like to clarify beer before packaging by cold-crashing, hold off on this step until your gravity is constant.
The idea of manipulating wort or beer pH to affect enzyme activity is interesting, but is not a method I would advocate. Although enzymatic rates are influenced by pH, it is not practical to change the pH of the wort/beer system enough to prevent the activity of this enzyme group without causing major changes to overall flavor and character of the beer. A similar method to pH manipulation is the use of heat to thermally denature enzymes. Although beer pasteurization is not considered cool in certain beer circles, it does work well to kill bacteria and yeast, and to denature enzymes in beer. This method is not practical at home, and does not make sense for control of hop creep in bottle-conditioned beer unless pasteurization is performed when proper carbonation is achieved.
