Ellagitannin, the main tannin in oak, is an important factor influencing the quality of grape wine in oak barrel.

鞣花单宁是橡木中的主要单宁,是影响橡木桶贮葡萄酒质量的重要因素之一。

However, there are some problems in ice grape wine production as follows: unqualified raw materials, raw materials by artificial freezing, addition of sugar, and dilution by grape fruitade etc.

目前冰酒生产仍然存在原料不符合规范要求、采用人工冷冻处理原料、补加糖分和用浓缩葡萄汁稀释等弊端。