共查询到20条相似文献,搜索用时 15 毫秒
1.
Extracts of hops made with liquid carbon dioxide can be substituted for dry hops to introduce the flavour of hop oils into beer. Apparatus has been devised so that such extracts can be redissolved in liquid carbon dioxide and then metered into beer. Successful trials have been carried out on the commercial scale. 相似文献
2.
D. R. J. Laws C. M. Grimmett G. Bett R. W. Scott A. S. Marsh A. G. Wheldon 《Journal of the Institute of Brewing》1983,89(1):28-33
The introduction of carbon dioxide hop extracts dissolved in liquid carbon dioxide to green beer during transfer from fermentation vessel to cold conditioning tank results in a sound dry hop flavour in the finished product. A system has been developed for injecting a solution of extract into a beer main. Extracts which are rich in hop oils are particularly suitable for imparting hop character to beer and a liquid-liquid countercurrent procedure is described for producing extract fractions containing enhanced levels of essential oil. 相似文献
3.
A method is described for imparting hop character to beer using extract prepared by treating hops with liquid carbon dioxide. The long contact times required for conventional dry-hopping techniques are avoided, and the use of liquid carbon dioxide as a medium for dispersal of the extract obviates problems due to residual organic solvent or emulsion stabilizers. Beers in which hop character was introduced in this way were found to be similar in flavour to control beers treated with portions of the same hop extract dissolved in ethanol. 相似文献
4.
Several varieties of hop have been satisfactorily extracted using liquid carbon dioxide in a plant operating on the 1 kg scale. The extracts have been used in small scale (0·6 and 16 hl) and production scale (700–800 hl) brewing trials where both ales and lagers were produced. All beers were of sound quality and could not be distinguished organoleptically from controls brewed with either hops or commercial hop extracts. 相似文献
5.
T. L. Peppard 《Journal of the Institute of Brewing》1981,87(6):376-385
The nature of volatile organosulphur compounds occurring in hops and hop oils is reviewed. The effect of such compounds on beer flavour and their practical importance to the brewer are also discussed. 相似文献
6.
D. R. J. Laws N. A. Bath J. A. Pickett C. S. Ennis A. G. Wheldon 《Journal of the Institute of Brewing》1977,83(1):39-40
Extraction of hops with liquid carbon dioxide at ambient temperature provides an attractive means of producing hop extracts which are rich in α-acids and free from hard resins, polyphenols, pigments and residual organic solvents. The resulting yellow extracts give beer with a clean bitter flavour when they are added during wort boiling. Manufacturing costs using the process are likely to be substantially less than in a conventional hop extraction plant. 相似文献
7.
Hop oil emulsions prepared from different varieties of hops have been found to exhibit enhanced physical stability on the addition of blends of the emulsifiers Span 20/Tween 80 or Span 60/Tween 60. Examination of the particle size and volume distributions of an emulsion by use of a Coulter Counter was found to be an excellent method of monitoring its stability. An indication as to the relative efficiency of emulsifiers can be obtained from Coulter Counter measurements on hop oil emulsions after storage for 4 days. The use of an ultracentrifuge provies a rapid means of testing emulsion stability and hence the effectiveness of emulsion stabilizers. 相似文献
8.
The time course of the extraction of α-acids by liquid carbon dioxide was investigated and it has been established that there are two zones with greatly differing rates of extraction. The rate in the first zone is governed by ‘solubility’ effects, while in the second zone the rate is limited by ‘diffusional’ effects. Consequently the rate of extraction in the first zone depends upon the flow rate of liquid carbon dioxide while that in the second zone depends upon the time of extraction. The effects on extraction performance of the depth of the bed of hops and the extent of milling were also explored. 相似文献
9.
A procedure is described for determining the solubility of hop α- and β-acids in liquid carbon dioxide. Results have shown that the optimum temperature range for the extraction of hops with liquid carbon dioxide is +5 to +10°C. A number of pesticides used by hop growers are appreciably soluble in liquid carbon dioxide. 相似文献
10.
F. R. Sharpe C. M. Grimmett D. R. J. Laws G. Bett 《Journal of the Institute of Brewing》1980,86(5):234-241
When a column containing powdered hops is extracted with liquid carbon dioxide, chromatographic separation of hop components occurs. They are extracted in the order essential oils, β-acids, α-acids; and the separation is enhanced when finely milled hops are extracted. Early fractions (~0·5 hour) contain a high proportion of the available essential oils when hops are extracted at ?20°C and such extracts are suitable as a replacement for dry hops. Fractions can be obtained from extractions at ~7°C which are rich in α-acids and contain low levels of β-acids. Small amounts of fats and waxes are normally present in fractions collected towards the end of a run when seeded hops are extracted. 相似文献
11.
T. L. Peppard 《Journal of the Institute of Brewing》1978,84(6):337-340
The precursor of dimethyl trisulphide (DMTS) in hops is destroyed by sulphur dioxide during kilning, but then re-forms slowly during storage. A redox mechanism is suggested and S-methyl-cysteine sulphoxide is postulated as the DMTS-precursor. The effect of DMTS on beer flavour is described. The flavour threshold value for DMTS in a commercial beer has been found to be 0·10μg/litre. 相似文献
12.
R. W. Scort P. D. Theaker A. S. Marsh C. M. Grimmett D. R. J. Laws F. R. Sharpe 《Journal of the Institute of Brewing》1981,87(4):252-258
Liquid carbon dioxide hop extracts were prepared for use as a substitute for dry hops. Many of these extracts were oil rich fractions containing up to 14% (w/w) hop oil. Extracts of Styrian Golding, Wye Target and Wye Northdown hops were used to treat ales prior to completion of beer processing and subsequent packaging. Emulsion/suspension systems were developed as carriers to facilitate addition of these extracts to beers before the chilling process. A loss of hop character from beer was found to occur during fining and filtration. Beers, treated with the extracts, exhibited natural though varietally distinct dry hop character. Production scale trials using these extracts have been successfully carried out to dry hop a brewery conditioned draught bitter and to match a traditionally dry hopped premium pale ale. The quantities of extract used indicated that economies in hop usage can be achieved when substituting liquid carbon dioxide hop extracts for dry hops. 相似文献
13.
A procedure is described for the analysis of fatty acids (C12-C18 individually and C18+ as a group) in hops, hop extracts and isomerized hop extracts, and analytical results are quoted for twenty-one different samples of hops or hop products. Isomerized extracts varied widely in their content of fatty acids and isomerization and processing of hops appeared to eliminate some fatty acids selectively so that isomerized extracts were enriched in palmitic acid, linoleic acid and linolenic acid. Some hop extracts had a surprisingly high content of lauric acid. The analytical results are discussed in relation to gushing. 相似文献
14.
《Journal of the Institute of Brewing》1973,79(4):310-315
The E.B.C. has standardized a method of analysing hop-extracts for Lead Conductance Value (LCV). Where additional values, e.g., total and soft resin, are required, the methods of the German Commission for Brewing Analysis have now been adopted. 相似文献
15.
Hops in which the essential oil content has been reduced by steam distillation under vacuum lose α-acid on storage more slowly than do untreated hops. 相似文献
16.
A method is described which allows the rapid determination of the bittering value of isomerized hop extracts. The method is also applicable in the case of isomerized hop extracts containing impurities such as α-acids and β-acids. 相似文献
17.
Two chromatographic procedures for the analysis of iso-α-acids in isomerized extracts have been tested. Although one of the methods—a variant of the Hansen, Hetzel & Miller procedure—performed better than the other, it still falls short of the demands of commercial transactions. The methods available for the assay of iso-α-acids are reviewed. 相似文献
18.
A new analysis for hop acids in hops and hop extracts is described. It is based on recent developments in high pressure liquid chromatography using pellicular anion exchange column filling material. Quantitative evaluation of α-acids, β-acids and oxidation products in hops and hop extracts is carried out by standard addition of pure humulone. The α-acids are completely separated from other hop substances before quantitation. The results of α-acids determinations must therefore be more accurate than was formerly possible and they are compared with conductometric titration results which are systematically higher. This is to be expected as it becomes more and more obvious that paper strip and conductometric analysis are not selective enough and determine fractions as “α-acids” which are in fact oxidation products of the hop acids. 相似文献
19.
A method is described which allows the separation of hop bitter components and derivatives present in hop extracts by thin-layer chromatography on a mixture of silica gel and cellulose. This method can be used to evaluate the purity of hop extracts, isomerized hop extracts and complementary base extracts. 相似文献
20.
G. K. Buckee 《Journal of the Institute of Brewing》1981,87(6):360-364
Since brewing companies are now reluctant to accept hops treated with sulphur during kilning and cultivation, methods have been developed for detecting such contamination. In the procedure for estimating residual elemental sulphur, milled hops are continuously extracted with cyclohexane and dissolved sulphur is deposited on copper gauze as copper (I) sulphide. Hydrogen sulphide is then formed by the addition of hydrochloric acid and is absorbed in potassium hydroxide solution. The dissolved sulphide is finally estimated by titration using p-chloromercuribenzoic acid and diphenylthiocarbazone as indicator. The modified Monier Williams procedure, as recommended by the Institute of Brewing for estimating sulphur dioxide in beer, has been adapted for analysing hops. This provides a convenient technique for determining whether or not hops have been treated with sulphur or sulphur dioxide during kilning. The sulphur dioxide content of fresh hops treated at normal rates is of the order of 800 mg/kg. A number of samples of hops from the 1980 crop have been analysed and the levels of sulphur dioxide were found to be within the range 1 to 80 mg/kg. It is likely that these low levels are the result of using fuel oils, which contain variable amounts of sulphur, to dry the hops. 相似文献