Don’t worry, be hoppy
It's a brewer's nightmare. You've dreamed and designed, you've planned, prepared and processed. Your beer is almost ready. After the fermentation is complete you add pressed hop cones, dry hopping for that extra aroma. Leaving the beer unfiltered to preserve the hazy look and feel, you bottle it. Finally, you can relax and enjoy the feeling of a job well done.
Then it all goes wrong. The hops are added and hop creep begins. This is almost undetectable as the fermentation process can even begin inside the bottle. Hop creep is very difficult to detect and may not be discovered until the beer is consumed. It increases Diacetyl, alcohol, and CO2 levels as well as decreasing pH and gravity. Excess diacetyl, above the flavor threshold, leads to unpleasant buttery flavors, and suddenly your dream beer tastes like movie popcorn.
Hop Creep was first studied as long ago as 1893 by the pioneering brewing scientist Horace T. Brown and his assistant G. Harris Morris. They called it "the freshening effect of hops" , and proposed three possible causes of refermentation; 1. hops could contain fermentable sugars, 2. hops could introduce wild yeast into the brew, or 3. hops contain endogenous enzymes which trigger the fermentation process anew. They found their third hypothesis was correct and that hop creep was caused by enzymes in hops.
Hops contain many types of enzymes, and the levels vary according to hop variety and season. Alpha amylases help break down simpler sugars, limit dextrinase debranches unfermentable starches, and beta amylases, glucoamylases and maltase enzymes break down starch into fermentable sugars. It is this last group of starch degrading enzymes that cause dry hop creep.
Usually enzymes from hops are deactivated by heat during boiling and all fermentation is stopped. Hop creep only occurs when amylolytic enzymes from hops are introduced during dry hopping. This can potentially lead to refermentation if there is adequate starch material for the diastases to act on, and yeast is present. Trendy, hazy, unfiltered beers such as New England style IPAs provide plenty of fermentable material for the hop enzymes to work upon. Hop creep has returned.
Beating hop creep
While it is possible to avoid hop creep by autoclaving hops at a high temperature and pressure to deactivate the enzymes, this isn't ideal as it significantly changes the hop flavor.
Luckily there is a better way. DuPont ALPHALASE® Advance 4000 is a flexible enzyme that works across a wide range of conditions to control diacetyl levels. ALPHALASE® Advance 4000 limits the formation of diacetyl by directly breaking down the diacetyl precursor 2-acetolactate into flavorless acetoin. When added at the start of the fermentation process, ALPHALASE® Advance 4000 not only prevents hop creep, but also reduces diacetyl formation during the main fermentation process, giving you a faster and more efficient fermentation and maturation period.
ALPHALASE® Advance 4000 protects you from hop creep, leaving you free to create the hazy, aromatic beer you've been imagining.