Spontaneous fermentation

Many foods such as alcohoHc beverages, pickles, cheese, and fish sauce are preserved by fermentation. Spontaneous fermentations by mixed populations of yeasts and bacteria are normally iavolved. Preservation results from a lowering of pH or the formation of ethanol. Yeasts do not produce antibiotics, although isolates of a number of species produce a toxia ("killer factor") lethal to other yeasts. 

Occasionally, to the disappointment of Recioto producers, fermentation spontaneously went to completion, resulting in a dry wine. This was a mystery, but occurred primarily when the winters were mild. The resulting product was described as bitter, rather than, as usual, sweet. Considering its sensory characteristics and structure, the wine could indeed have been referred to as "very bitter"—in Italian, amarone. Nonetheless, it was tasty, without off-flavors, heady, flavorful, but, unfortunately, not sweet. 

Yeast fermentation, (spontaneous or inoculation) (in stainless steel, wood or concrete) Pumping over, punch-down kB Draining i Racking off gross lees Pressing (early for rosd, late for reds) wjK Malolactic fermentation (spontaneous or inoculation) Fermentation... 

Spontaneous fermentations are used for wine production in Erance, some other European countries and in South America. In recent years, smaller California wineries have begun experimentation with spontaneous fermentations as well. They generally start more slowly than fermentations inoculated with commercial dried yeast, are more difficult to control, and may suffer from growth of undesirable contaminants. However, it is claimed that the resulting wines possess better organoleptic properties, particularly more complex flavor and aroma. 

Spontaneous emulsification, 10 127 Spontaneous fermentations for wine production, 26 468 Spontaneous fission, 21 304-305 Spontaneous ignition temperature, 7 438t... 

The problem of alcoholic fermentation, of the origin and nature of that mysterious and apparently spontaneous change, which converted the insipid juice of the grape into stimulating wine, seems to have exerted a fascination over the minds of natural philosophers from the very earliest times. 

The growth of malo-lactic bacteria in wines is favored by moderate temperatures, low acidity, very low levels of S02, and the presence of small amounts of sugar undergoing fermentation by yeast. It is frequently possible to inoculate a wine with a pure culture of a desirable strain of bacteria and obtain the malo-lactic fermentation under controlled conditions. The pure-culture multiplication of the selected strain of bacteria is difficult, however. It is also difficult to control the time of the malo-lactic fermentation—sometimes it occurs when not wanted, and at other times will not go when very much desired. For the home winemaker it is probably most satisfactory to accept the malo-lactic fermentation if it occurs immediately following the alcoholic fermentation. The wines should then be siphoned away from deposits, stored in completely filled containers at cool temperatures, and have added to them about 50 ppm S02. If the malo-lactic fermentation does not take place spontaneously and the wine is reasonably tart, the above described regime of preservation will likely prevent its occurrence. When the malo-lactic transformation takes place in wines in bottles, the results are nearly always bad. The wine becomes slightly carbonated, and the spoiled sauerkraut flavors are emphasized. 

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