Ale Yeast

IPA, Weissbeer, Marzen, Kolsch, Pale Ale, Rye. What’s the difference, and how do you figure out what to order when you’re out? In this segment, we’ll discuss styles and brewing methods of some of our favorite beers.

Yeast is a fungi; a plantlike single-celled organism that eats sugar and starches and creates carbon dioxide and alcohol. How does it do this?

C₆H₁₂O₆ = 2CH₃CH₂OH + 2CO₂ + energy

glucose (sugar) = ethyl alcohol + carbon dioxide

Without getting mired in Chemistry 101 definitions, yeast (which is all around us) finds sugars present in malted barley, grape juice, or even baking flour and converts them into alcohol and gas. The rich smell of baked bread? Thanks be to yeast. Champagne effervescence? Thanks again, yeast. Beer alcohol and bubbles? Yeast hits the trifecta.

In fact, many brewers consider themselves ‘yeast wranglers’ above all else. That’s because without yeast they’ll end up with a sugary, flat, beverage. So it comes down to the brewmaster to choose which type of yeast to use in his beer. This is where it gets interesting.

The only plot chart you'll ever need.

As you know from looking at a bar’s beer selection, there seems to be a neverending array of beer styles out there: Weissbeer, IPA, Pilsner, Stout, Lambic, and Pale Ale just to name a few. The most glaring difference between the styles comes down to two different strains of yeast: ale yeast Saccharomyces cerevisae and lager yeast Saccharamocyces uvarum. Sacchara-wha? The Latin name matters much less than what it does to the beer. One creates top-fermenting ales and the other bottom-fermenting lagers. Beyond this, all the beer styles you see at your local bar fit into these two categories.

So what’s the difference? Take a look next time you’re at a bar: ales will tend to be fruitier, spicier, and smoother. Think Guinness, Bass, Blue Moon, and Sierra Nevada. Lagers, on the other hand will be crisp, bright, and milder flavored. These are best served ice cold. Stella Artois, Yuengling, Heineken, Harp, and a multitude of macro-brewed names like Budweiser, Miller, and Coors are considered lagers.

Homework: Find both a lager and ale, and taste them side-by-side. What differences do you notice?

Coming up next week: lagers vs. ales Part II