FoodNet

Experimental cookery

1932

Page 134

Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
When to add sugar in jelly making. As previously stated, Tarr has found that the jellying strength of the pectin is lessened if boiled before the addition of sugar. Yet, if the sugar is added to the pectin and PROPORTION OF SUGAR AND JELLY YIELD 165 acid prior to boiling, the jelly strength is not decreased even when boiled as long as 42.8 minutes. Directions for making jelly often state to boil the juice for a certain number of minutes before the sugar is added. From Tarr's results it would seem a much better practise to add the sugar to the juice and concentrate it after the sugar is added. Long boiling of the sugar and fruit juice produces a darker-colored jelly, the extent of the darkening depending upon the juice and the length of time of boiling. With dark fruit juices this is not desirable, but it may improve the appearance of light-colored ones. To prevent darkening after the sugar is added, the jelly can be made in small lots so that boiling to the desired concentration can be accomplished quickly. In extracting the fruit juice too much water should not be added, as a large quantity of water only dilutes the pectin, and then boiling is required to concentrate it. Concentration o£ sugar in finished jell. Jelly can be made with a wide range or proportion of sugar to juice, from about 40 to 70 per cent in the finished jell. From the reports in the literature, the average per- centage of sugar in commercial jelly, unless acidity or pectin is abnormally high, varies from 60 to 65 per cent. The concentration of sugar desirable in the finished jelly varies somewhat with the juice from which the jelly is made. Thus gooseberry juice, which usually has a pH 2.6 to 2.8 and also has a high pectin content, is usually of better texture if the final concen- tration of sugar is short of or about 60 per cent. Cox states that for cran- berry sauce too stiff a jelly can be prevented by stopping the boiling process when the sugar concentration is somewhat below 60 per cent. Cox states that premature gelation can be brought about by too much pectin, acid, or sugar, or all three. For some fruit juices Tarr and Baker have found that 70 per cent of sugar in the finished product gives a jelly of good tex- ture. With higher concentrations than 75 per cent the sugar may crystallize from the jelly. Proportion of sugar and jelly yield in illustrations. In general, other factors remaining constant, the yield of jelly parallels the amount of sugar added. The gooseberry juice for the jellies in the illustrations is from the same source, so that the pectin content and viscosity of the juice were the same. The percentage of sugar in the finished jell is about 60, since all were boiled to 103°C. In Experiment 24 the yield of" jelly parallels the sugar added. See Figs. 15 and 16. The firmness of the different jellies varies. The 2 cups of juice boiled down yield less than ^ cup of jelly. It is very firm, hard, and difficult to pull apart. The percentage of sugar in it is not known, but both the pectin and acid have been enormously concen- trated. With }i cup of sugar to a cup of juice the yield is a little more than 34 cup of jelly. This jelly is very firm, solid, and hard. With ^ cup of sugar to a cup of juice the yield is a little more than ^ cup of jelly.