Why are hydrometers used

In fact, it is usual to have two separate instruments, one for heavy liquids, on which the mark 1. Many industries have more than one set of hydrometers, 1. For measuring density of petroleum products, like fuel oils, the specimen is usually heated in a temperature jacket with a thermometer placed behind it since density is dependent on temperature. Light oils are placed in cooling jackets, typically at 15 o C. Very light oils with many volatile components are measured in a variable volume container using a floating piston sampling device to minimize light end losses.

The function of the hydrometer is based on Archimedes principle that a solid suspended in a liquid will be buoyed up by a force equal to the weight of the liquid displaced. Thus, the lower the density of the substance, the lower the hydrometer will sink. Some historians credit Hypatia of Alexandria with the invention of the hydrometer although there is little evidence to support this.

Because the commercial value of many liquids, including sugar solutions, sulfuric acid , and alcohol beverages such as beer and wine, depends directly on the specific gravity, hydrometers are used extensively. A lactometer is a hydrometer used to test milk. The specific gravity of milk does not give a conclusive test to its composition since milk contains a variety of substances that are either heavier or lighter than water.

Additional tests for fat content are necessary to determine overall composition. An alcoholometer is a hydrometer which is used for determining the alcoholic strength of liquids. How to make jellies. How to bottle fruit. Red White Fruit. Refractometers pH Meters Thermometers Hydrometers. Stills Kits Books Yeasts Botanicals. Funnels Pressing Sundries Straining Bags. Setting up a community group - where to start!

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Elderflower Cordial 10 top tips on planting apple trees! Past Blogs Vinegar. What is a Hydrometer used for and do I need one? Using a hydrometer is an easy, four-step process.

Obtain OG Reading The increments of your hydrometer are there to show you specific gravity points. Calculate with Temperature Hydrometer readings are stated assuming a standard temperature of 15 degrees Celsius.

Repeat process Once the fermentation process is complete, take another gravity reading. Product Search. There is a bulb weighted at the bottom either with lead or mercury to allow it to float upright and lend stability in the water.

There is also a scale printed on its side to measure specific gravity. In order to ensure better accuracy, the reading has to be adjusted according to the temperature of the liquid at the time of measurement.

This scale also varies as per the industry application. For instance, the petroleum industry uses API gravity, chemistry and pharmacology industry use Baume scale, brewing and wine-making industry use Plato and Brix for the sugar-based liquid industry. A hydrometer is specifically used for measuring low-density liquids such as gasoline, alcohol and kerosene as well as high-density ones such as acids, brine and milk.

The only difference is that it will go deeper in high-density whereas it will not be less deep in low-density. During the use, it is placed in the container holding that liquid. The hydrometer is placed in a clear container of liquid, and the value at the surface of the liquid provides the specific gravity for the liquid. For greater accuracy, this reading must be corrected according to the temperature because the density of a liquid changes with temperature.

Use a special type of hydrometer known as a saccharometer and a thermometer to check the sugar content of wine or beer. The amount of solute in a solution may be determined by its specific gravity because the solute increases the density of the solution.

The precise sugar content of grape juice is of critical interest because this directly determines the amount of alcohol that it might eventually contain. The alcohol content of the finished product may also be determined by a specific type of hydrometer called an alcoholometer or proof and traille hydrometer. These types of hydrometers are typically calibrated to room temperature 20 degrees C , and in these cases, the temperature correction factor will usually be small.

Soils may also be graded with a hydrometer.