啤酒生产中铁离子的来源及控制措施

啤酒中的铁离子主要来源于原辅材料、设备管件及酿造用水等。对麦汁糖化、发酵及成品啤酒质量产生影响。控制铁离子含量的方法有:控制原辅料及所用水的铁离子含量;适当提高糖化醪液的p H;选用优良、强壮的酵母种;选用含铁较少的硅藻土助滤剂;选用耐酸不锈钢容器和管道,并作好防腐措施。     

啤酒中铁离子含量的控制

啤酒生产过程不可避免直接接触铁容器和铁管等。只有控制好溶入酒中的铁离子含量,才能最大限度的减少对啤酒质量的影响。1酿造用水的铁离子含量控制定期对酿造用水铁离子含量的检测是非常重要的。糖化停产后再生产时,要将投料用的冷水、热水管道中的水先排掉一部分后取样进行铁离子     

啤酒中有机酸及其对啤酒风味的影响

啤酒中有机酸即羧酸类物质，主要来源于酿造原料、麦芽生产、糖化麦汁制备及啤酒酿造过程中。啤酒中的有机酸是构成酵母细胞组织的重要物质，有利于酶作用，是组成啤酒风味物质成分之一。但是，若啤酒中的脂肪酸含量过多则会对啤酒风味稳定性不利，有机酸在啤酒中的含量、比例都将使啤酒风味产生重大影响。应控制好啤酒中的有机酸含量使之达到“酸而不露”。方法：①控制原料质量；②调节糖化用水；③调pH值，宜用乳酸、磷酸两种混合酸；④麦汁过滤一定要清亮；⑤严格控制好每道工序的工艺卫生；⑥选用优良的酵母菌种，并加强酵母管理。（丹妮）     

锌离子在啤酒酿造中的作用与控制

啤酒中锌离子来源于麦芽、大米、酿造用水、酒花。Zn^2 在啤酒酿造过程中可起到催化荆作用，与氨基酸结合形成Zn-氨基酸螯合物。在啤酒酿造过程中，可激活酶提高酶的作用；促进糖化、发酵；促进蛋白质合成及其稳定性；缓解某金属离子的毒性作用，促进挥发物质的产生和双乙酰的还原，缩短发酵时间，提高啤酒质量；但含量过量会使啤酒非生物稳定性降低，影响啤酒质量。通过对糖化过程和发酵过程的控制，可降低醪液pH值。加入少量小麦芽，加入适量ZnCl2，ZnSO4及酵母营养盐等，可实现对Zn^2 的有效控制，达到最佳酿造浓度。     

啤酒中铁离子含量的控制

啤酒酿造过程中铁离子（可溶性铁）对麦汁的组成，发酵性能和成品啤酒质量有不同程度的影响。糖化过程中铁离子含量较高，会抑制糖化的进行，加深麦汁色度；发酵阶段铁离子含量过高影响酵母的生长和发酵；清酒灌装以后如果铁离子含量过高，会加速氧化作用。优质成品啤酒中铁离子含量应〈0．10ppm，当铁离子含量〉0．20ppm时，会对成品啤酒产生不同程度的负面影响，当铁离子含量〉0．40ppm时，就有明显的金属腥味和氧化味。[第一段]     

酿造水中的锌离子对啤酒酿造的影响

啤酒中的锌离子来源于麦芽、大米、酿造用水、酒花。实验表明在啤酒酿造过程中,锌离子可激活酶的活性、提高酶的催化作用,促进糖化、发酵;提高麦汁中糖、氨基酸的含量;促进双乙酰的还原,降低双乙酰的含量;激活乙醇脱氢酶,降低乙醛,提高酵母活力,降低酵母死亡率;提高发酵度,缩短发酵时间。     

保持啤酒正常发酵及其操作方法

二糖化在糖化过程中,由麦芽或其他来源的酶,将复杂物质降解为酵母能同化的物质,同时控制麦芽汁的组成成份,适宜于酵母繁殖生长,并易于与麦糟分离。1.酿造用水酿造用水的水质成份,主要是影响到啤酒口味;并在糖化过程中形成不同类型的沉淀。无机盐类成份,对糖化与发酵是重要的,但某些金属离子(如铜或锌)含量过高,     

酿造用水处理的试验分析

水是啤酒的血液,好的酿造用水是保证啤酒风味质量的重要条件。因此,从建厂开始,啤酒生产企业就十分重视水源的选择。啤酒酿造用水的性质取决于水中溶解盐类的种类和含量,水的生物学纯净度及气味,这些成分对啤酒酿造的全过程产生影响。啤酒厂在选择水源的基础上,经常还要对酿造用水进行处理,但处理方法是有讲究的,处理不当会适得其反。国内啤酒厂在酿造用水的处理上大都采用加石膏改良和加酸改良。当酿造用水中 Ca~(2+)mg/L时加石膏进行调整;加酸改良不是依据水质,而是依据糖化过程需要控制的 PH 值。     

啤酒酿造过程中浑浊的成因及解决办法

对啤酒酿造过程中浑浊的原因和解决方法进行研究。结果表明,啤酒中的沉淀物主要来自于啤酒酿造过程中蛋白质的析出;可通过控制麦芽质量、糖化用水硬度、麦芽蛋白质分解温度、发酵过程充氧量等方法解决啤酒生产过程的蛋白质浑浊;由多酚物质引起的酒体浑浊主要是由于酚的聚合反应、蛋白质络合反应所产生,在糖化阶段利用PVPP处理可解决由多酚物质引起的酒体浑浊。     

啤酒酿造过程中铁离子的来源，变化及其对啤酒质量的影响

研究了啤酒酿造水、原料、添加剂及助剂中的铁含量和铁离子在啤酒酿造过程中的变化规律。原辅料及添加剂中均含有不同浓度的铁,硅藻土含铁量最高,大米最低。麦汁中铁离子浓度均值在0．29mg／L,发酵过程中部分被酵母吸收,大部分随沉淀物排出罐外。成品酒中的铁离子会促进啤酒羰基类化合物的生成从而影响啤酒风味质量,游离态铁离子会使啤酒货架期前期浊度值升高,而对啤酒色度无显著影响。     

Effect of wheat malt on the concentration of metal ions in wort and brewhouse by‐products

The ionic composition of brewer's wort depends on the raw materials and processing employed. The macroelement content is usually sufficient for yeast, but some of the microelements (mainly zinc) often need to be supplemented to the wort. Wheat malt is used as an adjunct in the production of beer, replacing up to 60% of barley malt. In this study, the effect of replacing barley malt with wheat malt on the concentration of magnesium, manganese, iron and zinc ions in brewer's wort was investigated. The ionic content of both the raw materials and by‐products were analysed. Similar amounts of magnesium ions were found in wheat malt and barley malt, whereas, manganese, zinc and iron were more abundant in the wheat malt. Nevertheless, wheat malt did not cause a significant change in ion concentration in the first wort (except for magnesium; its content decreased). The ionic content in the spent grains increased owing to wheat malt addition; the concentration of ions in the wort decreased after wort boiling (Mn²⁺ and Fe) or remained unaffected (Mg²⁺ and Zn²⁺). It was concluded that the ionic composition of the wort depends mainly on the removal rate of ions from the wort during mash filtration and hot trub separation, rather than on the actual amount of ions in the raw materials. Copyright © 2015 The Institute of Brewing & Distilling     

瓶装啤酒巴氏灭菌泡沫环成因及预防

啤酒泡沫环主要成分为高分子肽、多酚物质、碳水化合物、金属离子等。形成因素有：原料麦芽质量、酒花、酿造用水含Fe^2 高；麦汁的煮沸强度、煮沸时的pH值；发酵工艺等。预防措施有：选择优良的原辅料；工艺选择及工艺过程中的参数控制。（孙悟）     

125th Anniversary Review: Improvement of Higher Gravity Brewery Fermentation via Wort Enrichment and Supplementation

Intensification of the industrial brewing process, particularly the use of higher gravity worts, has been driven by increasing competition within the industry as well as the need to maximise the use of raw materials and minimise energy expenditure. These developments have, however, placed greater demands on brewing yeast strains, whose evolutionary history has not prepared them for the extreme conditions associated with higher gravity brewing. Various yeast nutrient supplements have been used or proposed to maintain yeast performance under stressful conditions. These have included specific metal ions, lipids and lipid components such as fatty acids and sterols and free amino nitrogen, usually supplied in the form of a complex yeast food. Correction of wort nutritional deficiencies may reduce stress sensitivity of yeast and improve fermentation performance. Potential negative consequences of altering wort composition must however be considered, as important beer quality attributes such as taste, stability and foam can be affected. Here, the various options for nutrient supplementation and their influence on yeast physiology and performance, as well as beer characteristics are considered.     

应用糖浆高浓酿造啤酒的工艺浅析

高浓酿造啤酒起源于20世纪70年代美国和加拿大，现已遍及欧美啤酒行业。其优点有：(1)提高糖化和发酵设备利用率，节省投资；(2)降低能耗和成本；(3)提高糖分的转化率；(4)提高啤酒非生物稳定性和质量；(5)可添加稀释水、麦芽提取物、酒花萃取物及糖浆生产多类型产品，灵活性较大。缺点有：(1)酒花利用率低；(2)起泡性和稳定性下降；(3)对啤酒酵母有不利影响；(4)发酵时间延长；(5)对水质要求严格；(6)需调整原料、糖化工艺和发酵工艺；(7)长期生产需专门的糖浆贮存设备和糖浆添加泵；(8)不宜酿造浓醇型啤酒。     

The Influence of Heavy Metal Ions on Beer Flavour Stability

In this study, the importance of iron and copper ions and their radical formation via the respective Fenton and Haber‐Weiss reactions was confirmed. Of the other heavy metals present in the brewing process in relevant concentrations, the impact of manganese ions on beer flavour stability has been elucidated. In contrast to iron and copper, manganese ions are not removed from wort or beer to any great extent during the process. Additionally, manganese shows a similar radical‐promoting effect to that seen with iron and copper. Its reactivity, and typically higher concentration than the other two metals in beer, appear to make manganese an especially potent pro‐oxidant in beer. The results of the investigation clearly indicate that there are other heavy metals influencing the stale flavour characteristics of beer, in addition to the well‐known metals, iron and copper. In contrast to the aforementioned ions, manganese does not enter the product by being leached out of a tank or from piping materials, but rather comes from the cereals employed in brewing. This finding, concerning the importance of manganese as a redox system in beer staling, can serve as a basis for a different approach in the choice of raw materials.     

葡萄籽百香果啤酒发酵工艺优化

该研究以大麦芽、小麦为主要原料,葡萄籽、百香果为主要辅料酿制啤酒,利用单因素试验考察混合主料（大麦芽、小麦与水）料液比、萨兹香型酒花添加量、混合辅料（葡萄籽、百香果与麦汁）料液比、初始pH值、酵母添加量和主发酵温度等因素对葡萄籽百香果啤酒感官评分的影响,并通过响应面优化葡萄籽百香果啤酒发酵工艺条件。结果表明,最优葡萄籽百香果啤酒发酵工艺条件为：大麦芽、小麦与水料液比1.0∶4.0（kg∶L）,初始pH值5.0,萨兹香型酒花添加量0.6 g/L,百香果汁添加量80 g/L,葡萄籽、百香果与麦汁料液比2.0∶1.0（kg∶L）,酵母添加量0.10%,主发酵温度21 ℃。在此优化发酵工艺条件下,葡萄籽百香果啤酒感官评分为88.44分,酿制的啤酒香气丰富有层次感,麦香突出,是一款理想的烈性啤酒。     

啤酒工厂微生物管理的探讨

在啤酒工厂，微生物的管理是一个系统工程，除了必要的设备，还必须建立从原辅材料到整个酿造和灌装生产过程的卫生管理制度以及工艺卫生操作规程，并注重平时的检查和检测。啤酒生产中的污染菌主要来自空气、水、原料、冷麦汁、酵母、设备和管路、助滤剂、添加剂、包装物料以及各种用具和操作人员，该文对这些环节中微生物的管理做了详细的说明。     

浅谈啤酒色度与苦味值控制的影响因素

啤酒色度和苦味值是容易被人们忽视的两个指标 ,但这两个指标很大程度上反映出产品的质量 ,应引起重视。影响色度的因素有麦汁色度 ,其涉及到原料及配比、酿造用水、糖化方法、pH值、糖化过程的生化反应、过滤质量、麦汁煮沸、酒花及酒花制品、添加剂等 ;酿造过程中的氧化作用 ,应尽量减少与氧的接触 ;发酵工艺条件 ;过滤介质的吸附能力及灌装杀菌和瓶颈空气含量。影响苦味值的因素有麦汁苦味值 ,包括酒花及制品质量、酒花添加量、酒花浸提时间、麦汁pH值、煮沸强度等。(庞晓)     

The Horace Brown Medal Lecture: Forty Years of Brewing Research

Horace Brown spent fifty years conducting brewing research in Burton‐on‐Trent, Dublin and London. His contributions were remarkable and his focus was to solve practical brewing problems by employing and developing fundamental scientific principles. He studied all aspects of the brewing process including raw materials, wort preparation, fermentation, yeast and beer stability. As a number of previous presenters of the Horace Brown Lecture have discussed Brown's achievements in detail, the focus of this paper is a review of the brewing research that has been conducted by the author and his colleagues during the past forty years. Similar to Horace Brown, fundamental research has been employed to solve brewing problems. Research studies that are discussed in this review paper include reasons for premature flocculation of ale strains resulting in wort underattenuation including mechanisms of co‐flocculation and pure strain flocculation, storage procedures for yeast cultures prior to propagation, studies on the genetic manipulation of brewer's yeast strains with an emphasis on the FLO1 gene, spheroplast fusion and the respiratory deficient (petite) mutation, the uptake and metabolism of wort sugars and amino acids, the influence of wort density on fermentation characteristics and beer flavour and stability, and finally, the contribution that high gravity brewing has on brewing capacity, fermentation efficiency and beer quality and stability.