A hydrometer is a tool that of which is used to measure how much fermentation has occurred in a bottle of beer or wine. This does not actually measure how much alcohol is present in the brew, but it can be used to estimate the level by taking a reading both before and after fermentation. The hydrometer measures the density of the liquid. It is an accurate tool, though the accuracy of the alcohol level will only be as accurate as the calculations of he who estimates it.
A hydrometer is only one way that can determine the level of alcohol present in brew. However, several other scientific apparatuses exist to do the same thing, though it is far more costly than a hydrometer. Knowing how to use the hydrometer clearly helps in measuring the alcohol level in brew. It is certainly not the tastiest way to tell, though! Knowing how to use a hydrometer as well as practicing sampling to gain experience will be a good way to enhance future measurements.
When getting a new hydrometer, it is necessary to first test it. In order to test a hydrometer, get a jar and fill it with enough water so that the instrument will float. Spin it so that it will dislodge any bubbles that are present in the water – bubbles might cause the reading in the end to be inaccurate, or too high. The hydrometer reads as 1.000 at 68 degrees Fahrenheit on the specific gravity scale when reading accurately. Whenever measuring brew, the specific gravity should always be at 68 degrees Fahrenheit. Make sure to read the number that is on the paper where the brew crosses the hydrometer’s stem.
Three scales are present on the hydrometer, though a home brewer should only be concerned with two of them: the Potential Alcohol and the Specific Gravity. Knowing the purposes for these scales are essential in learning how to use this instrument. The former of these scales are used in order to read how much alcohol could possibly stand to be brewed in the batch. The latter is used in order to compare the density of the brew with the density of the water.
The first measurement should be done by way of putting the instrument into the test jar with enough room temperature wort such that hydrometer floats. Make sure to take note of the measurements in the home brew journal.
Whenever it appears that fermentation is complete, make sure to repeat this process and take a second reading of the remaining potential alcohol. Subtract this number from the number initially taken, one can easily determine the level of alcohol that is present in the brew. The second reading will, in essence, read how much unfermented sugars, in combination with other unfermentables, remain within the brew. This, in turn, determines how much of the ingredients wound up as starches and dextrins, or it will determine that the beer requires a longer time to ferment.
At this point, as well as several other points throughout the process of brewing, it is perhaps imperative to taste the wort. Knowing the malt flavors, the sweetness and how it develops throughout the process, it will help towards developing a sensory knowledge in regards to brewcraft. This sensory knowledge, used in conjunction with the knowledge of using a hydrometer, will overall enhance one’s ability to both smell and taste the qualities of produced beer.
A hydrometer can also be used to determine whether or not fermentation has completed. In order to do this, readings should be taken two days apart from one another, the results compared. In the event that the results read the same as each other, then the fermentation is completed. However, if there are any changes in the readings, the beer was still in the process of fermenting.