Quá trình lên men bắt đầu khi men bia được thêm vào nước ép thu được sau khi nghiền nho. Quá trình này có thể bị còi cọc hoặc dừng lại bởi sự tăng trưởng nghèo của nấm men. Điều này có thể xảy ra nếu các điều kiện như nhiệt độ và ánh sáng không thuận lợi. | Barrels used to age wine in the wine making process. mature local vineyards especially those established in North America rely on yeast strains that are injected into the crushed grape suspension. The growth of the yeast will then occur in the nutrient-rich mixture of the suspension. The fermentation process begins when the yeast is added to the juice that is obtained following the crushing of the grapes. This process can be stunted or halted by the poor growth of the yeast. This can occur if conditions such as temperature and light are not favorable. Also contaminating microorganisms can outgrow the yeast and out compete the yeast cells for the nutrients. Selective growth of Sacchromyces cerevisiae can be encouraged by maintaining a temperature of between 158 and 167 F 70 and 75 C . The bacteria that are prone to develop in the fermenting suspension do not tolerate such an elevated temperature. Yeast other than Sacchromyces cerevisiae are not as tolerant of the presence of sulfur dioxide. 600 . Thus the addition of compounds containing sulf fermenting wine is a common practice. The explosion in popularity of home-base ing has streamlined the production process. Home purchase so-called starter yeast which is essenti consisting of a form of the yeast that is dorma addition of the yeast powder to a solution of grap sugar resuscitation of the yeast occurs growth fermentation starts. In another modification to thi yeast starter can be added to a liquid growth sou days. Then this new culture of yeast can be used the grape essence and sugar solution. The adv second approach is that the amount of yeast wh can be better controlled and the addition of l encourages a more efficient dispersion of th throughout the grape solution. Winogradsky column I s In a Winogradsky column the conditions change from oxygenrich aerobic at the top of the column to oxygen-deficient anaerobic at the bottom. Different microorganisms develop in the
