I love exceptions to the rule.
- I before E, except after C, or when sounding like A, as in neighbor or weigh (except for _weird, foreign, science, glacier, _and about 800 others).
- Thirty days hath September, April, June, and November. All the rest have 31 (except February, which has 28, unless it’s a leap year, in which case it has 29).
- Never boil grain (except in decoction mashes).
Outliers and irregularities add spice to life and keep us from falling asleep and into a heap of regimented monotony. And so it is with hybrid yeasts.
We all learn from day one that ales are made with ale yeast and lagers are made with lager yeast. Ales ferment at room temperature, and lagers ferment in the cold. Even those handy adhesive strip thermometers that adorn our carboys feature a nice 2–4°F (1–2°C) gap between the lager and ale thermal regimes (I call this the DMZ).
And yet there are beer yeasts that refuse to be categorized. So-called hybrid yeasts comfortably work within the space that would normally be too warm for lagers and too cold for ales. The hybrid category usually includes
- Altbier: White Labs WLP036 Düsseldorf Alt or Wyeast 1007 German Ale
- California Common: White Labs WLP810 San Francisco Lager or Wyeast 2112 California Lager
- Kölsch: White Labs WLP029 German Ale or Wyeast 2565 Kölsch
Blonde ale, cream ale, and American wheat beers are sometimes classified as hybrid styles as well, but these are less yeast-driven than the above. Blonde ale can accommodate a variety of yeasts, but Alt and Kölsch need Alt and Kölsch strains.
Let’s be clear. Hybrid yeasts are still either ale or lager strains, Saccharomyces cerevisiae or Saccharomyces pastorianus. When we refer to a yeast as hybrid, what we mean is that it operates outside its normal environment.
For ale yeasts, this means that the yeast strain continues to work well at temperatures considerably lower than is typical for ale strains—as low as 55°F (13°C). Lager strains that are classified as hybrid continue to exhibit lager-like characteristics at temperatures well above the usual lager range—as high as 65°F (18°C).
While these strains are naturally associated with the styles for which they are named, hybrids open up some convenient doors for the practical homebrewer. Brewers who may not have the equipment or space needed to ferment and condition lagers can pull off a good example with a California Common strain. Or they can brew up a pseudo-lager with an Alt or Kölsch strain.
To get started, try brewing our Echtes Festbier, but swap out the suggested yeast (Wyeast 2308 Munich Lager) with Wyeast 2565 Kölsch. Ferment it as cool as you can, and let it condition all summer long for an Oktoberfest party in the autumn. You and your friends will enjoy a lager-like amber ale that’ll fuel hours of oom-pah.