What is a Hydrometer Used For?

A hydrometer measures the relative density of a solution relative to the density of water. This is referred to as Specific Gravity. Sugar water will have a density that is greater than pure water. Ethanol has a density that is less than water. The hydrometer will sink further into a solution of alcohol and not sink as far into a sugar solution. Specific Gravity is unitless. It defines the ratio of the density of a solution to the density of water. Specific Gravity is calculated like so, Specific Gravity = (Density g/cm³)/(1 g/cm³).
In general a hydrometer is utilized to determine the sugar content of something that can be fermented. This could be wine must, beer or whiskey mash and even things that do not have anything to do with making alcoholic beverages. Hydrometers are scaled and calibrated for each distinct purpose. Such as, a hydrometer used to determine the sugar content and potential alcohol in a whiskey mash will usually measure the Specific Gravity within a range between ~0.990 - 1.180. If you're measuring distilled spirits you must have a liquor hydrometer which will have a proof range from 0-200 or a tralle range from 0-100. Here is some sample data that shows the Specific Gravity of a few popular solutions.

• Pure Water: Specific Gravity = 1.0 
• Pure Ethanol: Specific Gravity = 0.785
• 50% Ethanol: Specific Gravity = 0.8925

To calculate the sugar content and potential alcohol of your mash you need to use a beer and wine hydrometer. Simply take a sample of the mash and pour it into a tall graduated cylinder. The graduated cylinder can be a jar or something that is narrow and tall. Nevertheless, ensure that the cylinder is as tall or taller compared to the hydrometer. Next, lower the hydrometer into the graduated cylinder until it is floating. Give it just a little spin similar to a top to shake loose any air bubbles that might stick to the hydrometer. Now you are prepared to read the hydrometer. Examine the number on the hydrometer that is at the same level as the liquid. You can now determine sugar content and potential alcohol assuming that both measurements are on the hydrometer.

To learn more about using a hydrometer check out the article "What is a Hydrometer?" If you are using the hydrometer in the preparation of a whiskey mash or distilled product go to How To Make Whiskey Headquarters for recipes, techniques and discussion on this facinating subject.

Making the First Whiskey

In the Scottish highlands, several men gather wood and brush, return to their house and stoke the huge fire blazing beneath cauldrons of barley mash. It’s about 1150 A.D. and the men, monks shielded by giant monastery walls, are preparing a high-alcohol drink called “uisge beatha,” the breath of life (aqua vitae in Latin). Around Europe, the extraordinary cathedrals are just being started while using the new technique: the flying buttress. A Remarkable Crusade is underway inside the Holy Land.

The monks, when not distilling the very first known liquor which will be commonly known as Scotch whiskey, were growing food including the ingredients of the mash: barley and the fungi called yeast. The barley is soaked for several days, or “malted,” and after ground (mashed) and fermentation begins. Distilling occurs in copper vats, and the monks pour the distilate into oak casks which would have taken months to build and seal. The casks then sit for six months to many years. The safety and affluence of the monastery, and the frightened reverence the general public would have had for monks, guaranteed this to be one of the few secure places for producing whiskey in the High Middle Ages.

The first commercial distilleries appear at the conclusion of the 15th century, with written receipts for Scotch documented in 1495. As Europe urbanized and materials became more accessible, individuals could design and make more useful stills, those not open to the air and losing the vast majority of product to steam. Coils and other reduction devices for barley distilling came into use, and other grains became popular.


Meanwhile, on which would become the American continent, Native Americans were making alcohol from many native plants, including corn. Europeans arrived to see many foods and grains, and experienced corn whiskey for the first time. In Massachusetts, the Scots-Irish inhabitants settling in and sawing down vast hardwood forests knew how to proceed. They used whatever materials were available to make corn liquor, and as early as 1633 the Massachusetts Colony started demanding a license to distribute it. The struggle between governments seeking revenue and the people who wished to make their own rules about distilleries had commenced.

Of course, people had made wine and ale for much longer than this. Many beverages with alcohol were available, but the private enterprise problems that continue today had started. Before the revolution, still proprietors were left almost entirely alone. Washington and Jefferson ran their own stills. Following the revolution, taxes were applied to all alcohol to help pay war debt and farmers did not approve. Their stills had in large part grown to be their livelihoods.

The Whiskey Rebellion in western Pennsylvania was the greatest and best known of the battles moonshiners had with government agents, but the battles continued, large and small, throughout rural areas in the east. The Appalachian Mountains through Virginia, West Virginia, North Carolina and Tennessee eventually became renowned for moonshine whiskey and the many tales of backwoods distilling.

Now that your interests are peeked maybe it is time to explore the entire process of making whiskey. You ask "how to make whiskey?" The web is a great place to learn and educate yourself on the art. For more details check out How To Make Whiskey Headquarters. There you will find mash recipes, methods and discussions on still types.