That Louis Pasteur was onto something. Seriously.

People were harnessing the power of yeast to make beer for thousands of years before they actually knew what it was. Louis Pasteur figured out how it worked in the mid 1800s.

He proved that fermentation was not just a chemical reaction but caused by an organism: yeast.

There’s something magical about yeast. The yeast used to make ale is the same one used to make bread and many wines.

Yeast mutates quite easily and so can develop over time into different strains of yeast that give beer different characteristics—spicy, dry, fruity, caramely, honey-like,sulfury…

To my mind, it’s kind of like how Chihuahuas, Dobermans and Marmaduke can all be dogs.

Try a weiss beer (weissbier). The Whitehorse liquor store has three distinct weissbiers: König Ludwig, Schneider Weisse and Hacker-Pschorr.

These are German wheat beers brewed with a strain of yeast that gives the beer those crazy banana and clove aromas and flavours.

There is also a goodly amount of wheat malt used in the mash and, depending where you are in Germany, these types of beers are also referred to as hefeweizens(weizen means wheat, hefe means yeast).

The wheat gives the beer its fine head and subtle twang. The name weiss (meaning white) comes from the murky look of the beer due to suspended yeast because it’s unfiltered.

Try doing a side-by-side-by-side. Crack the beers and pour them into glasses with enough room to nostril-in without snorting the foamy cloud.

The König-Ludwig weissbeir has a grainy aroma and malty fruit flavour. The Schneider has balanced spice and fruit. The Hacker-Pschorr is banana-dominant with a good balancing bitterness.

I have a love-hate relationship with banana, so this one is my least favourite. But you can decide which one works for you.

Yeast is unicellular. That is, it consists of one cell. It eats sugar and creates carbon dioxide and ethanol as byproducts.

Some beers you buy (e.g., many German wheat beers) are bottle-conditioned, which means that the carbonation in the bottle is natural (rather than pumped in artificially) and is caused by the yeast eating residual sugars and building up carbon dioxide levels in the bottle.

These bottle-conditioned beers have sediment in the bottom—the white slick residue that consists mostly of spent yeast cells. The bonus is that these bottle-conditioned beers actually store better than filtered beer.

There’s something about having this living organism in the bottle (albeit dormant) that acts as a preservative for the beer.

Yeast has been around on Earth fermenting stuff for millions of years. In the mid-1990s a scientist at California State University was mucking about with a 45 million-year-old piece of amber (fossilized tree sap) and discovered dormant yeast within it.

Years later, the scientist cultured the yeast, increasing its population, and collaborated with a brewmaster to create a unique beer—Fossil Fuels Pale Ale.

From the tasting descriptions I have read, it sounds a bit like a hefeweizen, with its clove and fruity character. In reality, it`s probably more of a publicity stunt and conversation starter, but an interesting curiosity nonetheless.

Yeasts live in their own special world. They don’t need sunlight to grow (unlike plants). As primitive life forms (members of the fungi kingdom), they can live without oxygen and they have strange sexual habits.

Yeasts reproduce by budding. In my science-fiction mind, I imagine it to be like growing a second head and having it break off and become its own person.

Weird, and not entirely accurate, but a good visual.

These yeasts are tiny things— one thousandth of a millimetre across, give or take. So small and inconsequential, yet they bring us so much joy.