Must hydrometer

Alcoholometer. This hydrometer is used in determining the density of aqueous ethyl alcohol solutions the reading in degrees is numerically the same as the percentage of alcohol by volume. The scale known as Tralle gives the percentage by volume. Wine and Must hydrometer relations are given below. 

See also below under Wine and Must Hydrometer. 

Wine and Must Hydrometer. This instrument has three scales. One scale shows readings of 0° to 15° Brix for sugar (see Brix Hydrometer above) another scale from 0° to 15° Tralle is used for sweet wines to indicate the percentage of alcohol by volume and a third scale from 0° to 20° Tralle is used for tart wines to indicate the percentage of alcohol by volume. 

Most-sirup, m. arrope (boiled-down must). -wa(a)ge, /, must hydrometer, -wein, m. a lightly fermented fruit juice, motivieren, v.t. give the reason for motivate. 

The general layout of work benches, including hoods, was described in Chapter 2. Now comes the decision about where there should be drawers, cupboards, or other features. Small, shallow drawers, for instance, are just right for storing hydrometers and similar pieces of equipment and should be close to where these are to be used. Burets also need shallow drawers, but they must be wide. Certain pieces of glassware need fairly deep drawers. Much equipment calls for cupboards of certain sizes. 

For solid and semisolid materials, a pycnometer is generally used (ASTM D70), and a hydrometer is applicable to liquid materials (ASTM D3142). It is worthy of note at this point that the density (hence, the API gravity) of residua show pronounced changes due to the effects of temperature and pressure (Table 11.1). Therefore, isolation of the sample after leakage or spillage must also allow for equilibration to ambient conditions before measurements are made. 

To use a hydrometer, simply float it in the solution to be evaluated and note the level. Temperature control is imperative. Also, the hydrometer must be cleaned and dried prior to immersion, so as to avoid contamination of the sample. 

These are typically based on the principle of the hydrometer. For automatic measurement and control an inductance bridge may be employed to detect the position of the hydrometer. The level of the liquid in which the hydrometer is floating must be maintained constant. The float or displacer may be partially or totally immersed in the liquid (similar to the float systems used to measure level—Section 6.5.1 and Fig. 6.28). A schematic diagram of an instrument using a totally immersed displacer is shown in Fig. 6.35. 

Introduction. Air becomes incorporated into juice during processing or upon reconstitution of concentrates. The incorporated air must be removed if the Brix of the juice is to be determined by hydrometer. It is essential to deaerate juice when determining the color with a colorimeter. The color is slightly less affected by air when visual comparisons are made. 

In using the hydrometer, it must be remembered that the change of density recorded by the hydrometer is not of a particular cross section of the sedimentation cylinder, but depends upon the depth to which the hydrometer is immersed. The hydrometer method can be applied only to suspensions which are of very small size since rapid changes in density of the suspension cannot be read on the hydrometer. ... 

For accurate work it is necessary to take into account certain correction factors, namely the meniscus correction and the change in suspended material, it is necessary to make readings at the top of the meniscus. Hence, there must be added to the latter a small quantity to correct for the procedure. In the case of water suspensions this correction is about 0.0003, and this figure is generally used. 

Baume hydrometers for use with this table must be graduated by the above formula, which should always be printed on the scale. 

Prior to electrowirniing zinc, all zinc plants must purify the electrolyte, and in particular cobalt has to be removed, usually by cementation with zinc powder. Such a cement can be re-processed to recover its metal values, in particular cobalt. Hydrometal S.A. a subsidiary of Jean Goldschmidt Int. S.A. (JGI) processes such cobalt-containing cements at its plant in Engis, Belgium (31). Cements from various sources are treated, with typical content of 15-20% Cu, 2-5% Ni, 20-30% Zn and 5-7% Co. A simplified process flowsheet is presented in Figure 16. 

---