by Mike Retzlaff
The brewing of many sour beers including Berliner Weisse, Gose, Lichtenhainer, & Lambic styles requires planning ahead. Such beers really need well aged hops. These beers have no hop aroma or flavor, and very little bitterness. The hops are there only for their preservative power. Such beers rely on a bacterial inoculation to provide their distinctive sourness. Normal hopping rates inhibit bacterial growth and would make these styles un-brewable.
It is the lupulin in hops which provides stability to beer through its anti-microbial properties. Normal use of hops has the added bonus of aroma and flavor; not something wanted in a Lambic.
Leaf hops are the traditional and preferred form although pellets will work. Most of us have found an old packet of hops that sat in a cupboard or on a shelf in the garage and were forgotten. When opened, they were cheesy smelling and I don’t mean like a fine, sharp cheddar! When hops oxidize, some of the hop oils revert into a soft resin, the soft into a hard resin, and eventually pass into isovaleric acid. This is the cheesy smell. If left exposed to air for a longer period, the cheesy smell eventually goes away and the hops are ready for the kettle. If you have hops which have degraded to the point of losing their color and most of their aroma, these would be fine candidates for further aging. There are a few ways to accomplish the aging.
- The traditional way is to age them for 2½ to 3 years in the loft of the brewery.
- Take your hops out of any packaging and dump them in a brown paper bag. Roll the top of the bag and staple it shut or close it with a binder clip. Use a ball point pen to identify the contents and date before putting the bag in your attic. The heat generated up there will usually do the trick in a few months. (Don’t use a magic marker as it will transfer its odor into your hops.)
- Put fresh hops on a cookie sheet and bake them @ 150o – 190o F for an hour (any hotter makes them toast). Afterward, leave them out in open air for 2 to 3 days. Then you can bag them and store until brew day.
In less than a year, “normal” hops will lose a third to a half of their bittering qualities if stored at room temperature. Some hops have really poor keeping qualities and won’t last that long. Start with low alpha acid hops like Hallertau and Goldings instead of the big boys such as Citra and Columbus as there is a smaller amount of resins to deteriorate.
The use of aged hops in a boiling wort can require four to six times the normal quantity. Remember that you are using them for their preservative properties instead of for bitterness, flavor, and aroma. It is not uncommon to use 3 – 4 or more ounces in a five gallon batch.
Residual IBUs will drop slightly as the beer ferments. During the aging process (either in bottle or cask), the preservative components of hops can break down. Brettanomyces, if used, will eat some of the hop resins and the bacteria will then eat whatever the yeast couldn’t.
If you have no desire to brew sour beers and have some old hops stuffed away in a box, on a shelf, or even in the back of your freezer, don’t throw them away! If you don’t want to use them, give them to a fellow brewer at a club meeting. CCH has several sour beer brewers and any of them will surely appreciate your gift and put it to good use. Your gift might even inspire someone to try brewing sour beer! If there is enough buzz among the members, perhaps a group might get the Director Undertaking Massive Brewing Operations (DUMBO) to designate a sour beer Brew Off; who knows?