Lovely mixes

(Up to 10 minutes reading time) The brewer’s trade is one of those cases where the name doesn’t really ring true. Let’s be honest – a brewer just “sets the table” and then waits, hoping that after the feast the result will be as close as possible to what was intended. This is why the words “yeastman” or “yeast farmer” are often mentioned ironically at brewers’ meetings as the true names of the trade. In recent years, the term mixed fermentation has come up quite often . These are those ales in which the brewer deliberately sets the table for more than one yeast or bacterial culture.

In search of purity

First, a little digression – any beer before the 1880s was a blend. A large proportion of small brewery ales, as well as a number of world-famous Belgian brewery ales, are still blends. Any beer in which more than one yeast or bacterial strain has been involved in the fermentation is called a blend, with the result that the ability to predict the outcome is reduced by the increase in the number of variables, while the multiplicity of flavours and aromas increases. It is important to mention here that the brewer should know that the beer will be a blend before it reaches the final consumer. Otherwise, it is simply bad beer. I wonder if there is a more important time in the beer industry than the mid-19th century! European brewers have recently introduced the thermometer, which allows more precise preparation of sugars for leavening. Experiments are under way that will make it possible to cool the wort and control the fermentation and storage temperatures of the beer, regardless of the season or how much ice is left in the cellar from last winter. It will be possible to brew beer all year round, not just from October to March (we have a longer brewing season). But the most important push comes from Louis Pasteur, who declares that fermentation is the responsibility of a living organism. Breweries are feverishly buying microscopes to look at their smallest employees. And in 1883, in the Carlsberg laboratory, then and still the leading scientific institution in the beer industry, Christian Hansen separates a single yeast cell, feeds it with sugar and is able to grow the first pure yeast culture.

Mixtures

All this is unimportant, because when making a blend, it is rarely a task to “throw out” beers with the same taste and smell and the same labels through the brewery door. A mash is a unique fixation of the passage of time in the bottle – different micro-organisms are allowed to coexist in the same mash to produce the richest possible bouquet of flavours. It is not even a question of objectively measurable quantities such as sugars, proteins, starches, vitamins, water composition, the number of different yeast cells, the amount of air in the wort, the proportions of the tank, the fermentation temperature and pressure, all of which can be reproduced, but of the interaction between the different micro-organisms, where the human ability to calculate the result is still limited. Below is a list of the most popular “actors” who tend to appear in different proportions on the stages of the mixed taste. Each genus is rich in tribes, each with its own idiosyncrasies reflected in the taste and/or smell of the beer. Almost all can still be found in the wild:

Genus Saccharomyces

Mainly known for Saccharomyces cervisae , responsible for wine, cider, honey, beer and all other fermented beverages, it is the most studied micro-organism in human history. The great diversity of tribes allows for different beer styles. Slightly different from these is the lager yeast Saccharomyces pastorianus, which can perform the same task cleanly at lower temperatures, allowing malt and/or hops to dominate the flavour of the beer. Both love sugars, give alcohol and a tribal flavour nuance, as well as carbonation. A fast and predictable workhorse throughout the fermenting world.

Genus Brettanomyces

A few decades ago, only Belgian brewers and winemakers from certain regions considered the representatives as welcome guests. Like Saccharomyces, it loves sugars but does not eat starch or protein, is considerably slower, can produce various quantities of acetic acid alongside alcohol, and the famous horse blanket. It is the spicy, mature smell and old taste of horse blanket that breeders usually want to achieve in their mixtures when introducing members of this genus. At the same time, they should always be patient, as the desired flavours can take several years to develop. Mixtures of the genus Brettanomyces:

Genus Lactobacillaceae

Best known for dairy and vegetable cooking. In beer, it mainly brings acidity of various kinds. From juicy citrus to slightly bitter. Usually plays on the flavour stage in pairs with the alcohol level, covering or even replacing it. Loves sugars but prefers lactic acid to alcohol. In the wild lives on malted grains, plants, fruits and vegetables. It is hops that it dislikes most, which is the main reason why hops are present in almost all beers.

Genus Acetobacteraceae

Most often, it is not the first number that makes it into the beer. When wild yeasts are brewed or raw berries or fruit are used, members of the acetic acid genus are often present in the beer. Although slow, they are very determined migrant workers who chew the alcohol and convert it into acetic acid. Loves heat and oxygen, dislikes sulphites.