from left, 2nd shift brewing co.'s katy, six mile bridge's bavarian hefeweizen, and rockwell beer co.'s passing clouds photo by izaiah johnson

How yeast affects your favorite St. Louis beers

As one of the four main components in beer, yeast is a crucial ingredient when considering a brew’s overall sensory impact.

Whether a brewer chooses to ferment hot and quick or slow and cold is in large part a direct response to what microorganisms – i.e., yeasts – they select to turn their sugar water (aka wort, in beer-speak) into beer; and depending on the temperature and amount of yeast used, the same yeast profile can yield different flavors. Will a yeast profile influence the drinker’s experience? It’s a valid consideration, not only for distinct beer styles like farmhouse ales, sour beers and hazy IPAs, but also for a brewery’s individual style and overall portfolio.

Many ale yeasts, which ferment quickly at hotter temperatures, are hyper-expressive; they lend beer beautiful aromatic and tasting complements known as esters. These fermentation byproducts are what give hefeweizens their banana-forward flavor or Belgian wits a bubblegum note. And that’s just the tip of the ale iceberg!

On the other hand, yeast strains that respond well to lagering – a technique that allows for colder fermentation over longer periods of time – are significantly less expressive. Unlike ale yeasts, yeasts used in lagering play a minor role in the flavor profile of the finished beer.

Due to increased market competition and beer drinkers’ general enthusiasm for novelty, the past several years have seen substantial innovation in the fermentation process leading to greater efficiency and efficacy. One such area is in the use of kveik yeast – kveik being the word for yeast in a particular Norwegian dialect. With strains that ferment out at high temperatures, kveik can work at upward of 90 degrees Fahrenheit (or even higher) – that’s 20 degrees hotter than the average ale yeast. This means a faster turnaround time for brewers, enabling them to get new brews in front of drinkers more quickly. Kveik strains can also produce ridiculously wonderful and juicy, tropical fruit-forward esters that pair perfectly with the ever popular, juice-bomb New England-style IPA.

A yeast isolate referred to as Lutra kveik has been deemed perfect for creating lager-like crushable beers due to the strain’s low ester profile and clean finish. This allows a brewery to create beers with lager characteristics without having to take the time or tank space to lager their beer. It’s the yeast of choice for local yeast-whisperer Jonathan Moxey at Rockwell Beer Co. for creating their German-inspired Berliner Weisse due to its ability to ferment at a very high temperature alongside souring agent lactobacillus. This process yields a clean (low ester), non-cooked finish like some kettle sours.

Another innovation is the much newer use of Sourvisiae yeast, a bioengineered, lactic acid-producing ale yeast that sours beer without the risk of cross-contamination. While the Kveik family has had a grand time at the hand of some of the city’s finest brewers, Sourvisiae is still in its infancy in the local beer scene. Recess Brewing, Public House Brewing Co. and Good News Brewing Co. have all introduced this bug into their brewing repertoires.

To experience a brewery showcasing their own house cultures (a mix of yeast and bacteria that’s harvested and selectively propagated) specific to their farmhouse beers, grab a tipple at Side Project Brewing, Perennial Artisan Ales, White Rooster Farmhouse Brewing, 2nd Shift Brewing or Wellspent Brewing Co.

Looking for a fruity, banana-bomb German-style hefeweizen? Schlafly, Urban Chestnut Brewing Co. and Six Mile Bridge Beer do a perfect rendition of this classic style. Or maybe you want a Belgian Wit experience that delivers hints of bubblegum alongside citrus, black pepper and coriander notes? Head to Rockwell for a pour of Passing Clouds Wit. While you’re there, don’t forget to try that Berliner.

If you are looking for tropical fruit-forward esters, head to Bluewood Brewing for an Arch City Haze or their new 2nd Shift collaboration, Get In. Both beers use the Kveik Hornindal yeast strain for its pineapple-rich aromatics.

Want to get in on that sour kick and looking for that Sourvisiae pucker perfect for spring? Head to Edwardsville and go check out what Recess Brewing has been up to with their Brainiac series. We hear there are sweet cherry and blackberry and strawberry and prickly pear variants right around the corner.

Not interested in anything to do with yeast flavor? You can always reach for that Bud Light Lime!

2nd Shift Brewing, 1601 Sublette Ave. #2, St. Louis, 314.669.9013,

Bluewood Brewing, 1821 Cherokee St., St. Louis, 314.261.4079,

Good News Brewing Co., 330 Sonderen St., O’Fallon, Missouri, 636.294.6593; 2886 S. Missouri 94, Defiance, 636.544.2965,

Perennial Artisan Ales, 8125 Michigan Ave., St. Louis, 314.631.7300,; Perennial on Lockwood, 216 W. Lockwood Ave., Unit B, Webster Groves, 314.682.3823,

Public House Brewing Co., 551 State Rte. B, St. James, 573.261.3333; 600 N. Rolla St., Rolla, 573.426.2337,

Recess Brewing, 307 N. Main St., Edwardsville, Illinois, 618.692.5101,

Rockwell Beer Co., 1320 S. Vandeventer Ave., St. Louis, 314.256.1657,

Schlafly Beer, multiple locations,

Side Project Brewing, 7373 Marietta Ave., Maplewood,; Side Project Cellar, 7458 Manchester Road, Maplewood,

Six Mile Bridge Beer, 11841 Dorsett Road, Maryland Heights, 314.942.2211,

Urban Chestnut Brewing Co., 3229 Washington Ave., St. Louis, 314.222.0143; 4465 Manchester Ave., St. Louis, 314.222.0143,

Wellspent Brewing Co., 2917 Olive St., St. Louis, 314.696.2919,

White Rooster Farmhouse Brewery, 113 W. Jackson St., Illinois, 618.449.2077,