The Influence of Beer Harmful Bacteria on Beer

According to German beer expert Professor Back, this paper divides beer harmful bacteria into five levels, namely: obligate beer harmful bacteria, latent beer harmful bacteria, indirect beer harmful bacteria, indicative microorganisms and latent microorganisms, which affect the taste of beer. It has a certain effect on the smell, or changes the appearance of the beer by forming cloudiness and precipitation.

1. Dedicated beer harmful bacteria

The obligate beer harmful bacteria have the greatest impact on the stability of beer quality. They can still grow well in the unfavorable environment of low temperature, anaerobicity, low pH value, containing hop bitterness and alcohol and lack of nutrients, and do not Requires a longer adaptation period.

2. Potential beer harmful bacteria

Only under certain conditions can potentially harmful beer bacteria grow in beer and cause harm, such as high pH value of beer, low bitterness value of hops, low fermentation degree, high oxygen content, and low alcohol content. Certain microorganisms only show the characteristics of beer harmful bacteria after a long adaptation period, and they also belong to potential beer harmful bacteria. Pay attention to such microorganisms in production, take effective measures to control their numbers, and do not allow them to exist for a long time in production. Otherwise, they will gradually adapt to the special environment of the beer.

3. Indirect beer harmful bacteria

Indirect beer harmful bacteria generally appear in the initial stage of yeast inoculation and fermentation, and will not cause direct damage to beer. But under certain conditions, they can still multiply during beer production, producing precursors that affect beer taste and ultimately adversely affect the quality of the finished beer.

4. Indicative microorganisms

Although the indicator microorganisms do not cause harm to the biological stability of beer, when they appear, they are often accompanied by the appearance of beer harmful bacteria, which are characterized by being relatively easy to detect. Indicator microorganisms appear when cleaning and sterilization measures are defective, or when there is a problem with the production process. According to practical experience, once the indicator microorganisms appear, we should take corresponding measures quickly to prevent the microbial status from continuing to deteriorate.

5. Latent microorganisms

In the identification of microorganisms, another class of microorganisms is often found, which are neither harmful beer nor indicative microorganisms. Such microorganisms only appear sporadically and irregularly, invading the production process through different routes up to the finished beer, and we call them latent microorganisms. The contamination caused by this type of microorganism is very short-lived. The main reasons for the contamination are the contamination of the production water and the construction maintenance on the production site. They are usually microorganisms that are ubiquitous in nature and can be found everywhere in the food production industry. Compared with other microorganisms, the difference is that its strong bacterial cells can survive in beer, and we can check them out by general traditional culture methods.