What is Sour Beer?



Sour beers are acidic, lively, tart, and complex. These beers often have a fruity taste: berry, cherry, peach, raspberry, or something else. Lost Signal Brewing explains what a sour beer is and how it’s made in today's post.


Sour beer isn’t some new brewing fad. Most beers throughout history used to taste pretty sour before the science of sterilization and pasteurization was discovered. The first purposefully-made sour beer came from Belgium, then from Germany.


Sour beers are made with wild bacteria and yeast strains. These play a huge role in giving it that “funky” sour-like taste. These “wild” yeasts are commonly Saccharomyces and Brettanomyces.


What Makes a Sour Beer Acidic?

Microbe Bacteria. Pediococcus (which gives beer a buttery flavor) and its cousin, Lactobacillus (bacteria that turns sugar into lactic acid), are bacteria commonly used in beer to turn it sour.


Brettanomyces are another bacteria strain that give beer an acidic taste. It’s also why sour beers are often referred to as “Brett beers.”


Best Food Pairings for Sour Beer

Rich, saucy meats or veggie skewers are the perfect fit for fruity, sour beers. Cheese is a natural best friend to sour beer. Lactobacillus is part of the cheese-making process.

  • Fatty cuts of beef

  • Deep fried meats

  • Spicy foods

  • Cured meats


How are Most Sour Beers Made?

We’ve got a signature mixed berry flavored sour beer — the Under the Tower Sour. It’s a delicious, fruity and tangy flavor mix that brings out the best of both worlds: sweety n’ fruity and slightly sour.


How's it made — usually:

  1. Start by making a mash (just like any other beer). Malted grain is mashed up by immersing it in water and heating it.

  2. Add your hops.

  3. Let the wort cool off. The sugar and water mixture is known as the wort. This has to cool. Once cooled, transfer it to a fermentation vessel, typically this is a carboy (a glass jug).

  4. Add the yeast. This is where you add the yeast strain, along with the bacteria, which could be lactobacillus and/or brettanomyces.

  5. Start the fermentation process. This can last anywhere between several weeks to several months. During this time, other fermenting agents like pediococcus can be directly added.

  6. Once the beer is soured, you should bottle it and age it. Put it in a cellar or an oak cask barrel. The aging process can last years, if you so choose.


Types of Sour Beer

Sour beers are risky and complicated to brew, given the careful balancing of compounds that has to take place in order for the beer to turn out balanced and flavorful.


The bacteria used to sour the beer is also known to aggressively devour sugar. So long as it’s done correctly, sour beers can come in a diverse array of flavors.


What are Some Traditional Sour Beers?

  • Belgian lambics

  • Gueuze

  • Flanders red ale

  • Oud Bruin


Fruited Sour Beer

Brewers often add fruit juice or preservatives to the beer brewing process to give it an extra fruity profile. After all, it’s pretty common to have fruity finishes on IPAs. But a fruited sour beer is essentially like drinking fruit juice with alcohol in it.


Gose Beer

Gose (pronounced “Goes-uh”) beer is a predominantly sour beer that comes from Goslar, Germany. Traditionally, this beer has an acidic, salty, sour, herby and tart lemony flavoring. It’s often made with coriander. As a rule, every Gose beer is sour. Yet, not every sour beer is a Gose beer.


Gose beer is also not to be confused with its Belgian counterpart and member of the lambic family, the Gueuze beer (pronounced “gooze”). Yes, this beer is also sour. However, it contains higher levels of carbonation and has a dry cider-like quality to it.


Sour Ale Beer

This beer is a regular ol’ ale — just with a more sour, tart taste.


Session Sour Beer

A session is any beer with a lower alcohol volume. The session sour beer is more of a marketing term. Simply put, it’s a low ABV beer with a sour flavor.


Lactose Sour Beer

Brewers use lactose in just about any style of beer: ales, lagers, IPAs and sours alike. It makes the flavor profile smoother, creamier and a tad bit more like milk. Here’s why.


The yeast converts most of the sugar to alcohol during the fermentation process. But the lactobacillus bacteria turns sugar into lactic acid. This milky sugar (lactose) isn’t fermentable. It never becomes alcohol. It just remains in the beer, giving it a smooth, sweet and creamy feel.


Kettle Sour Beer

This beer involves “sour kettling.” It’s the primary differentiator between normal sour beers and kettle sour beers. The base of the beer gets cooled in a kettle. Here’s how.


Making kettle sour beer involves going through the normal processes of making the wort (a mash of ​​gooey, sticky, syrupy sugars that form beer), then boiling it, cooling it in a kettle for a few days and adding some lactobacillus (the probiotic that turns sugar into lactic acid).


Smoothie Sour Beer

This one is a fun variant. It begins as a kettle sour beer, then fruit puree is added during the fermentation process to make it into more of a smoothie. Flavors can span from tropical mango to mixed berry blends. Sour smoothie beers are a challenge to brew correctly.


The reasons are many. Fermenting at a high gravity and with a high acidity is tough on yeast. Not to mention the fact that there’s a balancing act to be made between the various ingredients too, ensuring no one particular flavor overpowers the other.


Pastry Sour Beer

Speaking of being creative and inventive, this beer is basically a desert. It’s a newer style of sour beer. Oftentimes, pastry beers are porters or dark stouts made with chocolate (cacao), cinnamon or coconut. Pastry beer can be made from sour beers and include flavors like blueberry or cherry pie.


Come By Lost Signal Brewery for BBQ & Craft Beer

Drop by our brewery and barbecue restaurant in Springfield, Missouri, and have a delicious Under the Tower Mixed Berry Sour with our signature, award-winning barbecue ribs. Contact us for more information today!


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