Detailed method for making kvass from sweet potato

Kvass was originally a traditional fermented beverage of the Soviet Union, rich in nutrients, full of gas and foam, sweet and sour and refreshing. It not only has the fermentation aroma of malt and hops, but also contains a small amount of alcohol, making it a drink suitable for men and women, young and old. In addition to bread or dried bread as raw material, sweet potato starch can also be used as a raw material for making kvass, and the cost is low, with certain economic benefits.

1. Process flow: starch slurry saccharification -- enzymatic hydrolysis -- fermentation -- filling -- pasteurization -- finished product

2. Key points of process operation:

① Starch slurry saccharification: first make sweet potato starch into a slurry with a water content of 75%, stirring continuously. Then raise the temperature of the slurry; when the slurry temperature is 35-45°C, add 15-30 units of cytolytic enzyme per 100 grams of sweet potato slurry, and carry out enzymatic hydrolysis for 30-60 minutes. Then add pectinase, 15-30 units per 100 grams of sweet potato slurry, and act at 25-35°C for 30-60 minutes. Subsequently add α-amylase for liquefaction, liquefy at 60-70°C for 10-20 minutes, then add glucoamylase, and carry out enzymatic hydrolysis at 40-50°C for 20-30 minutes. At this point, the dextrin in the sweet potato starch slurry is completely decomposed into sugar.

② Enzymatic hydrolysis: to the above slurry treated with enzyme preparations, add protease to decompose protein. Add 15-20 units per 100 grams of slurry, keep warm at 45-55°C for 15-25 minutes, then raise the temperature to 95-100°C and keep warm for 1-2 minutes, so that the various enzymes lose activity and the enzymatic reaction stops. Then add boiling water at a ratio of 1:4, boil for 60 minutes, then cool to 25°C and filter.

③ Fermentation: inoculate the filtrate respectively with 2% brewer's yeast and Bacillus dai culture liquid, and ferment at 26°C for 16 hours. After fermentation ends, cool to 6°C and filter to remove the yeast.

④ Filling: under low temperature conditions, fill fresh kvass into glass bottles, then cap with a capping machine.

⑤ Pasteurization: in order to kill the actively growing cells, prevent the bacteria from further reproducing and fermenting, and ensure that the carbon dioxide content is within the normal range, thereby improving the stability and safety of the product, the fermented bottled kvass must be pasteurized. Place the bottled kvass into a cement tank or iron plate tank, add water to cover the bottle caps, raise the water temperature to 60-70°C, keep warm for 30 minutes, take out and cool, and it is the finished kvass product.