Hygiene hazards in beer production

In the process of beer brewing, the invasion of heterogeneous microorganisms is inevitable. The growth and reproduction of these microorganisms make use of wort (very good medium) or nutrients in beer, resulting in difficulties or abnormality in subsequent production, resulting in precipitation, precipitation of the finished beer. Turbidity and even its metabolites cause beer flavor and taste variation.

The bacterial species contaminated at different stages in the beer production process are different:

1. Saccharification stage 

Types of bacteria susceptible to infection: Lactobacillus thermophilus

illustrate:

At the beginning of saccharification, when the temperature of the mash is less than or equal to 50 °C, it is easy to contaminate, but it is beneficial to reduce the pH of the mash; above 50 °C, lactobacilli are not easy to grow, so it is not easy to contaminate bacteria.

2. The wort is cooled to the inoculation process 

Types of bacteria susceptible to infection:

①Coliform bacteria

②Wild yeast

③Acetobacter, Lactobacillus

Micrococcus, Bacillus subtilis, mold, actinomycetes, Flavobacterium mutans, etc.

illustrate:

①Coliform bacteria can still grow at 40°C, so it is necessary to prevent unclean water from being mixed into the wort. The bacteria multiply very quickly and can multiply millions of times within 7 hours. Infection with a small amount of bacteria will cause serious harm, and it is not easy to To eliminate, the intermittent wort used in continuous fermentation should pay more attention to this bacterial contamination.

②Wild yeast is often lurking in the gaps, threads, and litter of the pipeline, and it is easy to be brought in when the wort flows through the pipeline; there is also the possibility of being brought in from the repeatedly used yeast. The yeast is contaminated and can compete with the yeast for reproduction, and the fermentation is completed. stop growing before.

④Acetobacter and Lactobacillus are polluted in the wort, the growth is slow, the thin plate system is dead or unsanitary, and the sterilization is not complete; the sterile wind system is infected.

3. Fermentation stage 

Types of bacteria susceptible to infection:

① Flavobacterium mutans

②Lactobacillus pasteuri, acetic acid bacteria

③ coliform bacteria

④ Wild yeast

illustrate:

① Flavobacterium mutans is mainly contaminated when yeast is inoculated. Generally, the promoter of the yeast is infected with this fungus. This fungus can make the yeast compete for reproduction and stop growing before the fermentation is completed.

②Lactobacillus pasteurii and acetic acid bacteria are often found in the inoculated yeast. These two bacteria can grow during fermentation. Open fermentation is conducive to the growth of acetic acid bacteria, and closed fermentation is conducive to the growth of lactic acid bacteria.

③ coliform bacteria, which is contained in the yeast.

④The main source of contamination of wild yeast is the species of yeast. Although the contamination rate is very low according to the species, the contamination rate of wild yeast is high in the recovered yeast after fermentation.

4. beer storage stage 

Types of bacteria susceptible to infection:

①Acetobacter

②Lactobacillus

③Zymomonas

④coliform bacteria

illustrate:

Incomplete cleaning and sterilization of fermentation tanks; incomplete sterilization of beer storage tanks, bright beer tanks and beer filtering systems when serving beer;

①It breeds quickly when there is air in the upper part of the beer

②Grow under anaerobic conditions

③ Rapid development under anaerobic conditions, rarely found

5. Packaging stage 

Types of bacteria susceptible to infection:

Acetobacter

Lactobacillus

football fungus

Zymomonas

coliform bacteria

illustrate:

For packaging wine conveying system, filling machine wine tank, empty bottle, empty barrel, etc., it is heavily polluted in the packaging process.

Not all microorganisms entering the beer brewing process are harmful bacteria of beer. According to their harm to beer, these microorganisms can be divided into two categories:

Harmless symbionts:

Harmless symbiotic bacteria refer to mold spores and many aerobic bacteria, which cannot grow in beer, and even the special environment of beer can suffocate them; but if these microorganisms exist, it also means that there may be harmful microorganisms at the same time.

The so-called harmless to beer (relatively) microorganisms - refers to the microorganisms that cannot be reproduced in beer brewing, such as some good spore bacteria that do not cause beer to become turbid and turbid.

Harmful bacteria

Harmful bacteria refer to human pathogenic bacteria (such as coliform bacteria), or those microorganisms that grow and multiply under specific conditions and cause abnormal beer production process, or make beer rancid, stale, viscous, precipitated, and cloudy;

The species that belong to harmful bacteria are: wild yeast, Lactobacillus, Streptococcus, Pectinobacter, Megacoccus, Enterobacteriaceae, etc…