Single Hop Brewing

You beer geeks ought to enjoy this!  We're beginning our One Hop Wonder Series of American pale ales brewed with a single hop varietal.  While single-hop brews aren't exactly rare (rumor has it that Two Hearted Ale is a single-hop beer), what's unusual is that we'll let you know what hop is featured and you'll know that it's the only hop in the beer!

For you, and us, this will be educational.  While our first OHW is a popular recipe we've brewed before (Citra Pale Ale), from here on out it will be hops we're curious about or have never used before!  We'll try and keep the malt profile simple, and similar, in each brew so you can really focus on the flavor of the hop varietal.

The tricky part for us is selecting varietals that lend a pleasant bitterness to the brew as well as great aroma and flavor.  Some traditional aroma/flavor varietals, such as cascade, are a poor choice for bittering a beer due to the harsh bitter character they impart, and are therefore not an option when brewing with a single varietal.

Warning: the following is rated UG (Ultra Geeky).

So what makes for a  “pleasant bitterness?”

Bitterness in beer derives from the humulone, or alpha acid, present in the hop cone.  When we boil hops, humulone isomerizes (its molecular structure changes) into isohumulone, which is soluble in beer, and which has a very bitter taste.  IBUs, or International Bittering Units, denote, in milligrams per liter, the isohumulone content of beer.  “Normal” beer contains roughly 10-60 milligrams per liter isohumulone.

There are 5 varieties of humulone present in varying amounts in the hop cone.  One of these, cohumulone, makes up approximately 15-50% of the total humulone in the hop.  Isomerized cohumulone can impart a very harsh bitter character to beer, so we try to bitter our beer with hops low in cohumulone.

Citra is a great varietal for single-hop brewing.  It’s high in total humulone but low in cohumulone, making it a pleasant and economical bittering hop.  Its high essential oil content imparts plenty of aroma and flavor, and we think the essential oil profile lends a refreshing fruity/citrus character to the beer.  We hope you agree!