The Difference Between Quick Sour, Lambic, Spontaneous, Wild, and Solera Beers: A Guide to Sour Brewing Styles
The world of sour beers is vast, intriguing, and diverse, drawing beer lovers into a realm of complex flavors, ancient brewing techniques, and unpredictable fermentation processes. As the craft beer movement has exploded over the past few decades, sour beers have moved from the fringe of the beer world to become a beloved category of brews, offering everything from tart refreshment to wild, funky, and funky-flavored concoctions.
But navigating the terminology surrounding sour beers can be a daunting task, especially when brewers use terms like quick sour, lambic, spontaneous, wild, and solera interchangeably or in subtle variations that can confuse even seasoned beer drinkers. While all these terms refer to styles or methods of brewing sour beers, they involve distinct processes, microorganisms, and flavor profiles.
In this blog post, we’ll break down these five types of sour beers, highlighting their differences, how they’re made, and the characteristics that set them apart. Whether you’re new to sour beers or already a fan, this guide will help you understand the unique methods behind these wild brews and learn to identify the differences between them.
1. Quick Sour Beers: Speeding Up the Fermentation Process
The term quick sour is a broad one that refers to beers that achieve their sourness in a relatively short period of time, typically in a matter of hours to a few days. These beers are a modern innovation, often used by craft breweries that want to create a tart beer in a fraction of the time it takes to produce traditional sour beers. Unlike wild fermentation or barrel-aging processes, quick souring is a controlled, intentional process that allows brewers to quickly develop the tart and acidic qualities typical of sour beers.
The Process Behind Quick Souring
Quick souring usually involves the use of lactobacillus bacteria, which produce lactic acid. Lactobacillus can be found in a variety of environments, from yogurt to pickles, and in brewing, it’s used to introduce tartness and sourness to the beer without the need for the long and complex fermentation processes seen in more traditional sour beers like lambics.
Here’s how quick souring typically works:
- Mash or Boil: The brewing process begins as it does for most beers, with a mash and boil to extract sugars and create the wort. However, the boil is often shortened to avoid the destruction of bacteria that will be used for fermentation.
- Cooling: After the boil, the wort is cooled rapidly to a temperature that’s favorable for lactobacillus (usually between 90°F and 115°F or 32°C to 46°C).
- Lactobacillus Addition: Once cooled, lactobacillus cultures are added to the wort. These can either be commercial lactobacillus strains or wild lactobacillus that naturally occur during the cooling process.
- Fermentation: The wort is allowed to ferment for a few hours to a few days. During this time, the lactobacillus consumes sugars in the wort and produces lactic acid, which gives the beer its characteristic sour flavor.
- Brewing Continuation: After the desired level of sourness is reached, the wort is boiled again to halt the fermentation process. Yeast is then added, and the beer is fermented in the usual way to achieve carbonation and alcohol.
Flavor Profile
Quick sours typically have a clean, sharp acidity that’s straightforward and refreshing. The tartness comes primarily from lactic acid, giving the beer a smooth and well-rounded sourness that doesn’t carry the funky, barnyard flavors that you might find in wild or spontaneously fermented beers. Quick sours are often more approachable for newcomers to sour beer, as they provide a pleasant, easy-to-drink level of tartness.
Examples
- Sierra Nevada’s “Wild Little Thing” (a Berliner Weisse)
- Anderson Valley’s “Briney Melon Gose”
2. Lambic Beers: The Historic Spontaneous Fermentation of Belgium
Lambic beers are some of the most well-known and beloved sour beers in the world, originating from the Brussels region of Belgium. What sets lambics apart from other sour beers is their use of spontaneous fermentation, a process that relies on the natural wild yeast and bacteria found in the environment rather than adding cultured strains of yeast. This traditional brewing method is not only a hallmark of Belgian beer culture but also a fascinating example of how microorganisms can interact with beer over long periods to create complex, layered flavors.
The Process Behind Lambic Brewing
Lambics are brewed through a process known as spontaneous fermentation, which means that the beer is exposed to the wild yeasts and bacteria present in the air. Here’s how it works:
- Mash and Boil: Lambics start similarly to other beers, with a mash and boil. However, lambics are often brewed with a high percentage of wheat in the grain bill, which gives them a distinctive, hazy appearance.
- Cooling in Open Air: After boiling, the wort is cooled in large, shallow vessels known as coolships. These coolships are placed in open-air environments—often on the roofs of buildings in Belgium—where the wort is exposed to the wild yeasts and bacteria that populate the air. The cooling process usually takes several hours.
- Fermentation: Once the wort has cooled, it is transferred to wooden fermentation barrels (typically oak), where it is left to ferment. The wild yeasts, including Brettanomyces (Brett) and various species of Lactobacillus and Pediococcus, work together to ferment the beer over an extended period, typically from 1 to 3 years.
- Aging: Lambics are aged in these barrels for a significant amount of time, during which they develop their unique flavors. The extended aging process allows Brettanomyces and other wild microorganisms to produce complex aromas and flavors, such as earthy, musty, and funky characteristics that are highly prized by sour beer aficionados.
- Blending: One of the signature characteristics of lambic brewing is the blending process. Lambic beers often involve blending younger lambics (usually aged for one year) with older lambics (aged for two to three years) to create a more balanced and flavorful product. This is most famously seen in gueuze, a style of beer made by blending different-aged lambics.
Flavor Profile
Lambics are known for their unique, complex, and often funky flavors. The natural fermentation process produces sour, earthy, and occasionally barnyard-like flavors from Brettanomyces yeast. They may also display fruity notes from the presence of wild yeasts, along with a distinct dry finish.
While lambics can range in flavor, they generally have:
- Tart, puckering acidity (from lactobacillus and pediococcus)
- Funky, barnyard-like flavors (from Brettanomyces)
- Fruity undertones (apple, pear, or citrus)
- Complex and layered aromas due to prolonged fermentation and barrel-aging
Examples
- Cantillon Fou’ Foune (Fruity Lambic)
- Boon Oude Geuze (Gueuze made from a blend of lambics)
- Brouwerij 3 Fonteinen Oude Geuze
3. Spontaneous Fermentation: The Wild World of Natural Fermentation
Spontaneous fermentation is the process by which a beer ferments naturally by exposure to wild yeasts and bacteria from the environment. While lambic brewing is the most famous example of spontaneous fermentation, this technique can also apply to other sour beers made without adding cultured yeast strains. It’s a traditional method that relies on the natural biodiversity of microorganisms in the air.
Spontaneous fermentation can happen with or without the use of open fermentation vessels like coolships. Some modern brewers use controlled environments, but the core idea remains the same: fermentation is allowed to occur naturally through the introduction of wild microorganisms.
The Process of Spontaneous Fermentation
- Open-Air Cooling: Similar to lambic brewing, wort is cooled in open-air vessels, allowing wild yeasts to settle into the beer.
- Fermentation: The wort is then transferred to fermentation vessels—often open wooden casks or barrels—where it ferments with wild yeasts, bacteria, and other microorganisms. Unlike controlled fermentation, no specific strains of yeast or bacteria are introduced; instead, the microorganisms from the air and the environment dictate the fermentation process.
- Aging: The beer is aged for extended periods, typically several months to a few years, to allow the fermentation process to fully develop its complexity.
Flavor Profile
Spontaneously fermented beers tend to have a more complex and unpredictable flavor profile, with a combination of tartness, sourness, funk, and earthy flavors. The beers can exhibit wild notes that are far more diverse than what you’d find in quick sours or even traditional lambics.
Examples
- Cantillon’s Cantillon 100% Lambic
- Brouwerij Boon Oude Geuze
4. Wild Beers: The Fermentative Playground
The term “wild beer” is often used to describe beers that are fermented with wild or mixed cultures of yeast and bacteria, particularly Brettanomyces, Lactobacillus, and Pediococcus. Wild beers are brewed using more than just saccharomyces cerevisiae (the
yeast typically used in most beers), introducing wild strains to produce funky, complex flavors.
The Process of Wild Brewing
Wild beers are typically made with a variety of different microbes, including Brettanomyces, which produces the barnyard-like, funky flavors commonly associated with wild beers. These beers can be brewed with a variety of methods, from spontaneous fermentation to blending wild yeasts with cultivated strains.
Flavor Profile
Wild beers can vary greatly in flavor, but they tend to be more complex and funky than beers made with traditional yeast strains. Expect to encounter:
- Earthy, funky flavors (thanks to Brettanomyces)
- Strong, complex sourness
- Fruity and citrusy notes (depending on the microorganisms used)
Examples
- The Bruery’s “Rueuze”
- Jester King’s “Le Petit Prince”
5. Solera Beers: The Barrel-Aging Technique
Solera is a unique aging process that involves blending younger beers with older ones over multiple years, creating a layered, consistent product. While it’s more commonly associated with wine and sherry production, some brewers apply the technique to beer, particularly sour beers.
The Process Behind Solera Aging
- Aging in Barrels: Solera beers are aged in wooden barrels, with each batch of beer spending time in a barrel of varying ages.
- Blending: Periodically, younger beer is added to the barrel, and a portion of the older beer is removed for packaging. The process continues year after year, ensuring that the final beer maintains a balance of younger and older flavors.
Flavor Profile
Solera beers often exhibit rich, complex flavors with a balance of sourness, oakiness, and funk. The aging process allows the flavors to evolve over time, often resulting in a well-rounded beer with depth and smoothness.
Conclusion: Understanding the Sour Beer Landscape
Sour beers are an exciting and diverse category, encompassing a wide range of flavors, techniques, and histories. From the quick tartness of quick sour beers to the ancient, spontaneous process of lambics, the wild fermentation of wild beers, and the slow, deliberate blending of solera beers, each style brings something unique to the table.
Whether you prefer the clean acidity of a quick sour or the deep complexity of a barrel-aged lambic, the world of sour beers offers a taste for every palate. As craft breweries continue to experiment with these styles and innovate new techniques, the landscape of sour beers will continue to evolve—inviting drinkers to explore, discover, and savor the complexity of wild, spontaneous, and barrel-aged brews.
