Getting Started
Contents
Welcome!
The goal of this page is to welcome the new brewer to the world of sour beer and get started! This page looks at sour beer basics and what flavor progressions to expect along the fermentation timeline. We will (1) go over a few basics about sour beer, (2) look at how time affects wild beers, and (3) analyze some strategies for attaining certain flavor profiles. This page is targeted at the “beginner sour brewer", who shall be assumed as someone who has the basic “standard” brewing processes down and is interested in diversifying their fermentation process. Because this is an introductory page and links directly to the rest of the wiki, citations will be omitted.
Definitions
Sour beer is any beer inoculated with microbes other than traditional ale or lager yeast, whether you pitch with lab cultures, rely on microbes that have infiltrate your brewery, or add bottle dregs from a sour or wild beer.
A wild beer is one that has been spontaneously inoculated “in the wild”.
A clean beer is any beer that is not your wild beer; in other words your typical ale or lager.
A Brief Background of Yeast/Microbes
When brewing sour beer, there are a few more players to the “yeast” side of the ingredients list. In addition to Saccharomyces or “Sacch”, in wild beer brewing the brewer is often dealing with Brettanomyces, which is another genus of yeast, and Lactobacillus and Pediococcus, which are both bacteria. Acetobacter and enterobacter do play a part in some sour fermentations, however they are not often intentionally added.
Brettanomyces
There are two major species of Brettanomycesused in brewing: B. Bruxellensis and B. Anomala. Despite other strains mentioned, there are only five species of Brett, with these two being the species most commonly used in brewing. Brettanomyces produces what we will later refer to as the “funk” when it comes to wild beers. While it is capable of producing some acetic acid when in the presence of oxygen (think vinegar), funk is what is typically described. Despite providing desired funk and acetic acid, it is important to note that Brettanomyces can also be responsible for less desired flavors: feet, hard boiled egg, and some solvent-like nail polish flavors. Pure commercial cultures of Brettanomyces are available at most yeast suppliers. Brettanomycesdoes NOT provide a universal flavor. Just like the various Saccharomyces strains most brewers are familiar with, each Brettanomyces strain can produce a vast array of different flavors, depending on the particular strain, temperature and time.
Lactobacillus
Lactobacillus is a rod shaped bacteria that can grow with or without oxygen and produces lactic acid - most people are familiar with the sourness found in yogurt, sauerkraut , pickles, and so on. Lactobacillus converts sugars to lactic acid (and sometimes CO2 and ethanol). It can produce varying complexities of sourness from the one dimensional to the more complex, depending on which type is used.
Pediococcus
Pediococcus is a bacteria that also produces lactic acid, although generally slower than lactobacillus. The sourness tends to be thought of as more aggressive than Lactobacillusand is often thought to produce more of a complex sourness. It also produces off flavors (diacetyl) so it needs to have something to help clean up any unwanted flavors – like Brettanomyces, which converts it to other compounds with less aggressive flavors. There is some discussion that Pediococcus thought of “complexity” is merely perceived by brewers because it works longer than Lactobacillusdoes. This “complexity” could be simply because Pediococcus can lower the pH more than Lactobacillus.
Sourness vs. Funk
The flavors produced by some wild beers when using non-souring mechanisms are described as ‘funk’. Keep in mind that if you are choosing to use a wild yeast or bacteria, you want to have an idea of whether you’re looking for sourness or funk, and how much of each.
Funk
“Funk”, isn’t a common term for most of us in the food we eat. Descriptors of funk can be found in stinky blue/green cheeses, dank basements, some molds, and “on the farm.” When looking to achieve the funk, we’re going to be including Brettanomyces. When using Brettanomyces, we have two main species to pick from currently, and two very generalized flavor categories. B. Bruxellensis tends to produce a more funky beer, with emphasis on the “barnyard” characteristics Brett is commonly known for. Some flavor descriptors include horsey, smoky, spicy, barnyard, and the classic “sweaty horse blanket.” B. Anomala, on the other hand tends to lend fruity characteristics – pineapple, mango, and a low intensity “funk.” (although with time this can be more aggressive.) It is important to note Brettanomyces is capable of producing fruitier notes without the typical funk as well. However it can produce a lighter, fruitier funk that comes out as a delicate barnyard flavor with some varying notes of overripe tropical fruit.
Sour
Higher acid levels will give you sourness. Sourness is pretty easy to describe, as it is a flavor common to most of us in the acidic foods you keep in your fridge or pantry – lemons, limes, yogurt, sour patch kids, vinegar, etc. Most of us have probably tried sour foods with different levels of sourness and complexity from acidic fruit to lactic fermented vegetables. When we say complex, we're talking about layered acidity. Imagine drinking lime juice as simple sourness. A complex sourness would be lemon, lime, grapefruit, and pineapple juice combined.