Rhenish Hybrids

May 1, 2013 By Keith Klemp

The distinction between top- and bottom-fermented beers is familiar to all homebrewers, but the term “hybrid” is often met with curiosity. And while many of our styles were forged by the clash of ingredients, technology, and local and outside influences, there are a few that are defined by their own duality. California common and cream ale are two that Americans can claim as true hybrids.

The more elusive, though, are German Kölsch and altbier of the Rhine Valley. Not only are they quite different from all other German brews, but each is also distinctive enough to be the calling card of a city, and it is this provenance that sets them apart.

The two cities that they call home, Köln (Cologne) and Düsseldorf, are separated by barely 20 miles, but the cultural differences and rivalries are great. Ironically, the two beers share some essential brewing methods, and they are both something of a challenge to make well. If you’re up to the task, they can be brewed by following a few unique and rigid guidelines. Beyond that, the possibilities are actually rather broad if you want to make some interesting and very personalized hybrids, German-accented or otherwise.

Hybrid Defined

Kölsch and altbier combine top fermentation (typical of ales) and cold conditioning (typical of lagers). I love the self-explanatory, seemingly oxymoronic designation obergaerige lagerbier (top-fermented lager beer) that is often used to refer to these two indigenous German brews.

The yeasts used for both are specialized, selected over centuries to accommodate the environs and critical to their brewing. Tailored to the mild climate of the Lower Rhine Valley, Kölsch and altbier yeast work most comfortably at 55 to 65 degrees F, conditions that suppress the fruity esters and spicy notes associated with the ales of Britain and the other top-fermented brews of Europe.

Lagering is done at a modest 40 degrees F for about four to six weeks, warmer than the near-freezing condition of bottom-fermented lagerbiers. The character of the yeast and the lagering method suggest that these strains have been culled from bottom fermenters but adapted to slightly higher temperatures (much like the California Lager yeast used to make California common).

Beyond that, brewing Kölsch and altbier is merely a matter of selecting a proper grain bill and hop schedule, and selecting one of the several yeasts available to craft your homebrew. The stickiest requirement is ensuring that the yeast is comfortable during fermentation, always a consideration, but more so with these.

Brewing Kölsch

Kölschbier is the lighter of the two, always a shade of gold. This means, of course, that it is made primarily with Continental pilsner malt, and usually that malt alone. A simple bill of pilsner malt from Germany or Belgium, mashed for high fermentability, will produce classic Kölsch. Traditional wort strength is OG 1044 to 1048. I like to mash at about 148 degrees F, leaving little residual dextrine.

Malted wheat is not a stranger to Kölschbier grist, and it will add a bit of mouthfeel and depth. A touch of Vienna malt, up to 15 percent, will also provide extra character and deeper gold color.

Should you opt for a more dextrinous brew, mash into the low 150s, or use about 5 percent dextrine malt in the grist. Caramel flavors are not part of the Kölsch profile, so stick with dextrine malt over light caramel/crystal varieties. If you use American two-row malt, light specialty or toasted malt addition is advised. Extract brewers should use the lightest malt extract available, either on its own or with a touch of wheat or Munich malt extract.

Hop rates in the low- to mid-20s provide the perfect complement to the elegant malt character. Minimal aroma hops are traditional and, in a beer this delicate, even a meager aromatic addition will be noticeable. As one who loves to make classic versions of beers, I usually stick with German low-alpha-acid varieties such as Tettnang, Hallertau, or Hersbrucker, as well as Czech Saaz for aroma. American hops with German pedigree are also acceptable.

There are several Kölsch yeasts available from both Wyeast and White Labs; all of them are highly attenuative and will serve to retain the feathery malt character that you have so ardently striven to achieve. I have found that some lend an herbal character, enhancing the hops, while others provide a soft malty and even vinous note. As always, consult the vendor specs online.

Brewing Altbier

Since traditionally altbier is a shade of copper/amber, it is a bit more forgiving with grain bills and more accepting of diverse hop schedules. Even those found in the Düsseldorf Altstadt, the epicenter of altbier brewing, exhibit a range of hoppy profiles. Zum Uerige is considered the prototype. It comes in at 50 IBU, but most others are more balanced.

Decide for yourself whether you want a malt-accented, or hop-kissed brew. Maltiness can be achieved with a measure of Vienna, Munich, aromatic or Caramunich varieties. Mashing low will give the crisp, dry body and finish, without compromising the malt flavors.

Traditional altbier comes in at 4.5 percent ABV on average (OG 1044-1048). Just like Kölsch, altbier stays light on aromatic hops, but a hint of nobility in the aroma is a touch of grace. Spalter is the signature hop of altbier, but any of the German varieties will fit the profile.

If someone were to put my feet to the kettle, I’d go with a grain bill of 20 percent Munich, 75 percent pilsner, 4 percent Caramunich I and 1 percent Carafa I; 40 IBU, a modest addition of noble German hops at 15 and five minutes before knockout, and either Wyeast 1007 or WLP029. If mashed at 148 degrees F, this will give a crisp, lightly malty, aromatic and decidedly German character, with some mouthfeel and body provided by the secondary malts.

Base malt grist heavier on Vienna and Munich would also work well and create as authentic an altbier as any. The famous Sticke altbier from Zum Uerige is made a bit stronger and hoppier than its flagship altbier. It also makes a doppelsticke at 8.5 percent ABV.

Variations on the Theme

Now that I’ve offered some stodgy, classic guidelines, it is time to step outside the lines. The nature of the both Kölsch and altbier yeasts is one of adaptation and melding, able to cozy up to a variety of hops and malt. They go especially well with German ingredients, of course, so using that as a starting point, your recipe palette is relatively broad.

Kölsch yeasts play nicely with malted or flaked wheat or rye or even adjunct grains, and accent even the most delicate of hop schedules. Summertime wheat ales, heavy on American ingredients, with a slightly tart, quenching and herbal hop character, are impeccably brewed using Kölsch yeast. Cream ale and bière de garde are other options.

Something a little darker, with Vienna and Munich malts in the grist, higher ABV and higher hop rates, favors these yeasts rather nicely. Use that strategy to craft a well-hopped German “pale ale.”

Altbier yeasts are just as versatile and can handle generous doses of darker malts such as caramel and roast, and base malts such as wheat and rye. One of my favorite homebrews is a German-style “dry stout,” using pilsner, Munich, malted wheat and Carafa III in the grist, hopped to 40 IBU with Perle, finished with a German noble and fermented with altbier yeast. It will remind you of Guinness, with a German twist.

Malty amber and brown beer also favor the yeasts of Düsseldorf, even those in the 7 to 8 percent ABV range (especially bière de garde). Both Kölsch and altbier yeasts will offer full attenuation without suppressing, and even reinforcing, the malty notes. One thing to remember about these yeasts is that they are poor flocculators (sometimes called “dusty”) and will stay in suspension longer than most others. This is, once again, where patience and cold-conditioning come into play.

Both styles present an excellent chance to experiment with the new German hop cultivars for aromatic additions (Saphir, Opal, Smaragd). The fact that both are so well-adapted to the extensive pool of German ingredients especially, but American and Belgian as well, means that you are bound only by your imagination, unless of course, you want to create a Rhineland classic.

Classic Kölsch

All-grain, OG 1.045, 25 IBU

Mash 9# of German pilsner malt (or 7# pils and 2# wheat malt) for 1 hour at 148º F

Bittering hops: 7 AAU Hallertau, Tettnang or Perle, 45 minutes in boil

Aroma hops: 0.5 oz , Hallertau, Tettnang, Hersbruck, Saaz, 5 minutes before knockout

Ferment with Wyeast 2565, Wyeast 1010 or White Labs WLP029 according to yeast specs.

Lager at 40º F for four weeks before serving.

Extract: Substitute 6# Extra Light DME or 4# DME and 2# wheat malt extract for the grain.

Sticke Altbier (Strong Altbier)

Extract, OG 1.058, 45 IBU

Steep 1# Caramunich III and 1 oz Carafa III for 20 minutes

Add to the steeping liquid 3# Munich malt extract and 5# Light DME

Bittering hops: 10 AAU Spalt or Perle

Flavor hops: 1 oz Hallertau, Tettnang, Spalt, 15 minutes boil

Aroma hops: 1 oz Hallertau, Tettnang, Hersbruck or Saaz, 5 minutes before knockout

Ferment with Wyeast 1007, White Labs WLP036 (drier) or WLP011 (maltier) according to yeast specs.

Lager at 40º F for six weeks before serving.
All-grain: Mash steeping grains and 7# German pilsner malt and 3# Munich malt at 150º F for one hour.