在线测量麦汁浓度

应用在线分析仪对糖化过程中各测量点,尤其是过滤槽中的麦汁浓度进行每一秒的直接测量,有助于优化工艺。为了保证啤酒质龄,酒糟浸出不应过度,在过滤结束时准确地测定浸出物的浓度,能保证啤酒质量,同时提高麦汁的收得率。在线监测还能优化水耗、改进过滤时间,并降低成本。     

酵母增殖用麦汁浓度对其体积和发酵性能的影响

酵母增殖的麦汁浓度(OG)在7.5～17.5°P 范围时,随 OG 的增加会引起细胞体积的变化。这些变化可应用图象分析技术对单一细胞体积进行测定。ale 和 lager 酵母单一细胞体积的均值随 OG 增加,达到17.5°P 时,体积会增加30%。酵母于高浓麦汁(17.5°P)中增殖,及其后来于高浓麦汁中发酵,对其质量有不利的影响。对于标准的 ale 酵母分别于7.5、12.5和17.5°P 的麦汁中增殖,于17.5°P 的麦汁进行发酵,发酵结束的酵母活性分别为93、90和85%,而同样对于标准的 lager 酵母发酵结束时活性分别为98、95和89%。对于 ale 和 lager 酵母同样应用高于12.5°P 的麦汁增殖,再于高浓麦汁中发酵,发酵结束的酵母活性均不超过90%。     

微型自酿啤酒混合麦汁浓度的计算控制

微型自酿啤酒生产线的兴起，在宾馆，酒店形成一大景观，但是，精良的设备，新鲜的啤酒却常常达不到所要求的浓度，这不能不令人遗憾，本文通过计算找到一种控制其浓度的简便方法，从而提高自酿啤酒的质量便成现实。     

电导率监测在啤酒发酵过程中的应用

采用电导率测量的方法对啤酒发酵过程进行了研究,通过计算机的辅助实现了发酵过程中电导率的在线监测.结果表明:在啤酒发酵过程中电导率的变化遵循一定的规律性,并且将电导率与还原糖、酵母数等过程参数进行数学建模,同时将麦汁浓度、酵母代数对电导率的影响进行了比较.     

电导率在3种饮料酒发酵过程中在线监测的研究

该试验对酒精、葡萄酒和啤酒发酵过程中电导率与还原糖、酒精度之间的变化关系进行了研究,拟利用电导率来在线指示3种饮料酒发酵过程的终点.结果表明,在3种饮料酒的发酵过程中,电导率与还原糖和酒精度之间存在着一定的逻辑关系,利用电导率的实时变化能直接地反映还原糖和酒精度的变化趋势,但从产品质量的角度出发,该结论对于酒精发酵过程的在线监测具有更重要的理论意义.     

密度法检测啤酒原麦汁浓度的讨论

对采用密度法检测啤酒原麦汁浓度中的一些问题进行讨论，以便提高密度法检测啤酒原麦汁浓度的准确性。     

麦汁组分对酵母凝聚性的影响

多年以来，我公司啤酒生产使用的麦芽一直以进口大麦加工的澳麦芽为主，麦芽质量很稳定，没有出现过质量问题。但去年7月份以来出现了啤酒后酵过程酵母不易沉降的现象，滤酒前酵母数在800—1000万个，毫升，个别罐次达2000万个／毫升，严重影响啤酒过滤，造成硅藻土耗量增加，酒损上升。针对这一问题进行了系统的检查分析。     

啤酒酵母浓度实时在线检测方法的研究(一)

酵母的存在会改变发酵液的电特性,发酵液在无线电频率范围内的电特性可用电容率和电导率充分地描述。实验证实发酵液在无线电频率范围内的电容率增量是测量频率和生物量浓度的函数。基于对发酵液电容率分布的研究,本文提出了测量酵母浓度的新方法。用本方法不用取样就能对发酵液中的酵母浓度进行实时在线测量,而且测得的是活的酵母浓度。本文制作的电极直接插入 发酵器中并满足高温蒸汽 灭菌条件。本方法在生化制药、食品发酵、啤酒酿造、污水检测等工业领域里有很好的推广应用前景     

用电容率频谱法测量啤酒酵母的浓度和活性

酵母的存在会改变发酵液的电特性,发酵液在无线电频率范围内的电特性可用电容率和电导率充分地描述。实验证实发酵液在无线电频率范围内的电容率增量是测量频率和生物量浓度的函数。基于对发酵液电容率分布的研究,提出了测量酵母浓度的新方法。用本方法不用取样就能对发酵液中的酵母浓度进行实时在线测量,而且测得的是活的酵母浓度。本研究制作的的电极直接插入发酵器中并满足高温蒸汽灭菌条件。本方法在生化制药、食品发酵、啤酒酿造、污水检测等工业领域里有很好的推广应用前景     

THE CONTROL OF OXYGEN IN BEER PROCESSING*

The content of reducing substances in wort and beer at different stages of production can be estimated by measuring Redox Titration Values; dissolved oxygen is satisfactorily determined by means of the Hays Oxygen Meter. Taken in conjunction, these two figures can be used to indicate stages where oxidation is likely to occur and where particular care must be taken during processing in the brewery. Procedures are suggested for minimizing oxygen pick-up and the use of anti-oxidants is briefly discussed. The efficiency of yeast as an anti-oxidant during secondary fermentation is emphasized.     

家酿啤酒

介绍家酿啤酒的原料和酿制过程及探讨我国开发家酿啤酒的前景。     

THE ORIGIN AND OCCURRENCE OF VOLATILE SULPHUR COMPOUNDS IN BRITISH ALES AND LAGERS

A flame-photometric sulphur detector was used to identify, measure and determine the sources of the sulphur volatiles produced during the commercial processing of British ale and lager. Dimethyl sulphide was the main sulphur volatile present in malt but traces of hydrogen sulphide, diethyl sulphide, and dimethyl disulphide were also detected. Hops contained hydrogen sulphide, methyl mercaptan, dimethyl sulphide, diethyl sulphide, methional and dimethyl disulphide. Most of this material extracted into commercial worts was driven off during boiling. Brewing yeasts produced only traces of organo-sulphur volatiles both in laboratory fermentations of wort and during the processing of commercial ales and lagers. In contrast, brewery bacteria, particularly wort spoilage organisms, could generate dimethyl sulphide and sometimes traces of other sulphur volatiles in laboratory cultures. t-Butyl mercaptan was the only organo-sulphur volatile detected in significant concentrations during the primary fermentation and conditioning of commercial beers and this was attributable to the activity of wort-spoilage bacteria. Attempts to identify a volatile compound causing ‘sulphury’ smells in beer were unsuccessful but there was some evidence that it might not contain sulphur.     

THE CONTROL OF VOLATILE ESTER SYNTHESIS DURING THE FERMENTATION OF WORT OF HIGH SPECIFIC GRAVITY

Some effects have been studied of fermenting wort of unusually high specific gravity, followed by dilution with water to give beer of normal original gravity. This procedure permits increased overall rates of beer production, but matching of flavours requires control of the level of flavour determinants. If not controlled, the concentration of volatile esters may be disproportionately increased so that, after dilution, beer flavour is markedly different. Higher alcohol production is not affected in this way. The concentration of esters can be adjusted to appropriate levels by increasing the production of yeast mass during fermentation. Unsaturated fatty acids, which increase yeast dry matter production without altering the rate of fermentation, are particularly effective in reducing the extent of ester synthesis.     

糖化工艺对酵母沉降速率的影响

不同糖化工艺对麦汁中的糖分影响较明显,中温65℃时糖含量最低,低温长时间糖化可提高糖含量;糖化温度（68℃）最高时各种氨基酸的含量最高,中温（65℃）时各种氨基酸含量最低,低温（62℃）时各种氨基酸含量居中。糖化工艺对酵母沉降速度的影响：辅料大米用量达最大（45％）时酵母沉降速率最慢;糖化保温时间适中（30min）时酵母沉降速率相对较慢;加麦：澳麦=4：6时酵母沉降速率相对较慢;糖化温度相对较低或较高时酵母沉降速率相对较慢。（孙悟）     

RAPID METHODS FOR THE ANALYSIS OF THE FATTY ACIDS OF FERMENTING WORT AND BEER (C6-C10) AND YEAST (C6-C18)

Relatively rapid and simple methods for measuring the content of the free C₆-C₁₀ fatty acids in fermenting wort and beer and of the total C₆-C₁₈ fatty acids in yeast are described. The acids are extracted, after saponification in the case of yeast, using a small volume of chloroform and analysed by gas chromatography as free fatty acids. The precision of the procedures is reasonable.     

MALT FLAVOUR — TRANSFORMATION OF CARBONYL COMPOUNDS BY YEAST DURING FERMENTATION

Laboratory and pilot scale fermentations have been carried out using worts spiked with a range of carbonyl compounds, many of which are derived from malt. Aldehydes and vinyl ketones were chemically reduced during fermentation and could not be detected in the resulting beers; on the other hand certain saturated and non-conjugated unsaturated ketones were only partially reduced. The corresponding saturated alcohols and acetate esters were usually detected as transformation products.     

TRYPTOPHOL,TYROSOL AND PHENYLETHANOL—THE AROMATIC HIGHER ALCOHOLS IN BEER

A gas chromatographic method is presented for routine quantitative analysis of aromatic higher alcohols in beer. A satisfactory overall order of reproducibility, sensitivity and simplicity was achieved under the conditions described. This method has been used to compare finished Canadian ales and lagers. It was possible to differentiate an ale from a lager fermentation by the tryptophol content of the product. Experiments were conducted to investigate the influence of several factors on the concentration levels of aromatic higher alcohols. These compounds are produced by the yeast during fermentation and the levels achieved depend upon the type of yeast used, the fermentation conditions, and differences in the wort fermented.