White wine is the product of the fermentation of pure grape juice obtained from grapes by extraction from grapes. Macerations of the skins should be avoided and the must should be clarified by setting. One distinguishes two basic types, the dry, white wines and the sweet, white wines of variable sugar content.白葡萄酒是从葡萄中提取纯葡萄汁发酵得到的产品。避免葡萄皮的浸渍，葡萄汁通过沉淀澄清。人们把葡萄酒分成两种基本的类型，一种是干白葡萄酒，另一种是含糖量不同的甜白葡萄酒。
Extraction of the juice should be done rapidly to avoid oxidation and maceration. It consists of the following operation.提取葡萄汁应当迅速，避免氧化和浸渍。它包括以下操作。
(1) Crushing. This breaks the skins and permits the juice to run of the pump. Fragmentation and grinding of the berries should be avoided because they result in the formation of larger amounts of sediments.破碎：这是打碎葡萄皮，允许果汁可以泵送。应当避免碎裂和研磨浆果，因为这样会导致形成大量的沉淀。
(2) Draining. This can be static when the juice runs naturally from the crushed grapes. Generally one prefers dynamic drainage by means of vibrating screens or turning movements which accelerate drainage of the must and prevent oxidation.流出：这可以是静态的，让果汁从破碎的葡萄中自然流出。通常更喜欢动力的流出，通过振动筛或者旋转运动，可以加速果汁的流出避免氧化。
(3) Pressing. This permits extraction of the must remaining in the pulp. Vertical presses yield juice with little sediment because it has been filtered across a cake of pulp. But the system requires several successive pressings after crumbing and turning over of pulp. This is a lengthy operation and may lead to oxidation. Pneumatic presses permits a less damaging extraction, with better distribution, and better maintainance of the intergrity of the grape. With horizontal presses in which the pressure is not as high, the operation is more readily automated.压榨：这是允许葡萄汁在泵中运行。垂直压榨得到的果汁只有少量的沉淀，因为它经过了果肉滤饼的过滤。但是系统要求果肉破碎后要有几个连续的压榨。这是一个耗时的过程，还有可能导致氧化。气力压榨可以减小危险提取，更好的收率，更好得保持葡萄的完整性。水平压榨压力不是很高，操作更容易自动化。
(4) Clarification. This consists in the removal of insoluble particles suspended in the must. Clarification can be carried out by filtration, centrifugation, or more commonly by setting and decantation. Musts rich in sediment produce crude wines with a herbaceous taste. The presence of insoluble particles modify the constitution of the wines. Clarification is often carried out together with the addition of pectic enzymes to the must. The must contain colloidal material whose spontaneous hydrolysis by the enzymes of the grape can be accelerated by the addition of commercial enzyme preparations. Industrial pectic enzyme preparations may also contain cellulase, hemicallulase, xylanase, and protease. These enzymes catalyze the hydrolysis of plant cell wall materials to soluble compounds such as galactose, mannose, arabinose and methnol. The use of pectic enzymes in crushed grapes permits faster extraction of a larger volume of must. 澄清：这是除去悬浮在果肉中的不溶解的颗粒。澄清的完成通过过滤、离心、更普通的是沉淀和转移。沉淀多的葡萄汁加工的葡萄原酒含有一种生青味。不溶解颗粒的存在会改变了葡萄酒的成分。澄清通常和往果汁中添加果胶酶同时进行。果汁含有胶状物质，它可以依靠自身的酶水解，但添加商业的酶制剂可以加速这一过程。工业的果胶酶制剂可能含有纤维素酶、半纤维素酶、木聚糖酶和蛋白酶。这些酶促进植物细胞壁成分的水解成可溶解的混合物，如半乳糖、甘露糖、阿拉伯糖和甲醇。Treatment with bentonite is used to remove the proteins of the must and to prevent after-precipition that is sometimes called “protein floc”. Bentonite is an adsorbing clay. It is usually added before the fermentation to the clarified must at a rate of 60-100g/hl. After the fermentation it sediments without significantly increasing the volume of lees. This treatment also gives the wine a certain aromatic cleanness. 皂土用于除去果汁中的蛋白质防止后沉淀，它有时被称为“蛋白絮凝剂”。皂土是一种吸附粘土。它通常在发酵前添加到澄清的果汁中，添加量60-100g/hl。发酵后它的沉淀不会明显的增加酒渣的体积。
(5) Fermentation. The clarified must is stored in casks or more often in tanks. Fermentation is carried out anaerobically at a temperature below 20℃. The fermentation is considered complete when the residual sugar is less than 2g/L. The this point SO2 should be added at 6-8g/hl and the wine should be clarified as quickly as possible by filtration or centrifugation. Prolonged storage on the yeast containing lees can cause the development of sulfhydryl compounds of disagreeable odor. If a malo-lactic fermentation is desired, the wine remains on the lees without sulfating until the mali-lactic fermentation has taken place. The wine is then sulfited and filtered. Among the sweet white wine one distinguishes often the semi-dry wines, mellow wines, and sweet wines without a proper range of residual sugars for each types. 发酵：澄清的果汁贮存在木桶中，更多是在罐中。发酵完成是在温度低于20℃厌氧条件下。当残余糖分少于2g/L我们认为发酵完成。这个时候应当添加SO26-8g/hl，葡萄酒应当尽快的澄清（过滤或离心）。延长酒泥中酵母的保留时间，可以增加巯基化合物，带来不愉快的气味。如果需要进行苹果酸-乳酸发酵，沉淀物上的酒体不需要硫化处理，直到完成苹果酸-乳酸发酵。葡萄酒硫化、过滤。在甜白葡萄酒中一个区别于半干、半甜的是，甜葡萄酒没有一个确定的残糖范围。
