Spontaneous fermentation
The spontaneous fermentation is a fermentation type in which the alcoholic fermentation by naturally in the vineyard and in the cellar occurring yeasts without the addition of specially cultured yeasts occurs. It is still mainly used today by fabric owners for the production of distilling mashes from fruit . This is also a common practice when making fruit wines at home .
Wineries that value terroir also often use spontaneous fermentation as an oenological process and as a marketing tool for differentiation. It is rarely found in the brewing industry in Germany today , but is still quite common in the production of Belgian beer specialties ( Lambic , Gueuze ).
differentiation
For the production of alcoholic beverages, one uses predominantly pure yeasts , which are selected and characterized. The traditional consumer as well as the manufacturer always accept a certain degree of standardization , a trend towards leveling out or towards uniform taste and less differentiation.
In order to better differentiate products from a marketing perspective, some of the producers are increasingly relying on spontaneous fermentation. With it, the natural yeasts of the environment are propagated in the respective substrate and give the product a distinctive taste thanks to their unique natural microflora . However, the producer also has to accept the risk of incorrect fermentation.
Competition of life
In the natural microflora, the sugar mushrooms play a subordinate role. First, the wine yeasts are apiculatus - yeasts (genera: Kloeckera , Hanseniospora , Hansenula and Candida ) dominated. Under the conditions in the vineyard or the orchard, these naturally have better chances of survival and reproduction. Other common yeasts also occur. During mashing it is important to create favorable conditions for the fermenting saccharomycetes in order to achieve the purest possible fermentation and to suppress those organisms that adversely affect the end products.
Fruit mashing
Fruit mashes are often made from overripe fruit. There are numerous yeast strains here, most of which have already started the fermentation process in the field. Pure fermentation could only be achieved here with an oversized dose of vaccination . This is often not done. Instead, a change in the pH value can be considered as a control measure. The lowering of the pH value is intended to inhibit the further development of harmful microorganisms. For this purpose, sulphurous acid (for fruit wines) or sulfuric acid (for distilling mashes) is used.
Wine must
Until the 1970s, wine was mostly the product of spontaneous fermentation. Yeast approaches from the Zeltingen , Bingen- Scharlachberg , Geisenheim and Burgundy races can already be read in old specialist wine books. Only the large-scale production of dry yeast in pure breeding brought the spontaneous fermentation, which had been widespread up to then, to the side. The cultured yeast could be realized by means of freeze drying or particularly gentle drying. In the meantime, however, the natural yeast flora of the location is being partially reflected and the terroir idea is that, among many other influencing factors, the yeasts on the berry skins and in the cellar are characteristic of the location and should be expressed in the product. The results of modern research on the microbiology of must and wine should, however, flow into the actions of the cellar master.
Wort
The risk of incorrect fermentation in the brewery is much higher because the wort substrate does not have the low pH value of wine must. Because of the boiling of the wort, which is then cooled in a sterile manner, the natural yeasts have to be supplied in other ways. The hot wort is cooled in the refrigerated ship . The wort is inoculated through contact with a predefined range of germs from the ambient air . So that this offer does not lead to spoilage (of the beer), the yeasts and a conglomerate of other microorganisms are pre-bred. In the space above the reefer ship, this conglomerate lives from the sugar content of the rising steam. The selection process of the yeasts and bacteria for spontaneous beer fermentation takes place through the supply of nutrients and the strongly aerobic environmental conditions. Here lies the advantage of Saccharomyces, which are facultatively anaerobic , i.e. H. energy production or survival can take place both through breathing and through fermentation.
The selection process is a never-ending process. The resulting conglomerate usually consists of the following yeasts:
- Brettanomyces bruxellensis (spontaneous fermentation ~ lambic)
- Brettanomyces lambicus (spontaneous fermentation ~ lambic)
- Saccharomyces cerevisiae (top-fermenting yeast)
- Saccharomyces uvarum (bottom-fermenting yeast)
- Saccharomyces carlsbergensis (bottom fermentation yeast)
- Torulaspora delbrueckii (top-fermenting yeast)
See also
Individual evidence
- ↑ https://www.wein-und-markt.de/service/mitarbeiterschulung/was-ist-das-eigentlich-spontangaerung
- ^ Hugo Schanderl , Julius Koch , Erich Kolb: fruit wines . Ulmer, Stuttgart 1981, ISBN 3-8001-5518-4 .
- ↑ Hans Joachim Pieper, Ernst-Erich Bruchmann, Erich Kolb: Technology of the fruit distillery . Ulmer, Stuttgart 1977, ISBN 3-8001-5814-0 .
- ↑ Karl Kroemer , Gottfried Krumbholz: Investigations on osmophilic sprouts . Plant physiological research station Geisenheim a. Rh. , Geisenheim 1931.
- ^ Richard Meißner : The cooper's wine book . 2nd Edition. Ulmer, Stuttgart 1921.
- ↑ Julius Wortmann : Use and effects of pure yeast in winemaking . Parey, Berlin 1895.