How does one know the proper way to use a hydrometer?
As every homebrewer knows, a hydrometer is an essential piece of equipment. It lets you know when fermentation has completed and it can be used as a gauge to determine the alcoholic strength of the final product. But how does one know the proper way to use the hydrometer? Should it be placed directly into the carboy, right smack in the middle of the wort/beer mixture? Or is there a better and more accurate way to use this important device?
First, let’s cover the basics. A hydrometer is an odd- looking, floating device that looks like a thermometer but is used to measure the density (specific gravity) of your homemade beer. It is very important as a tool to gauge when fermentation has completed. As the yeast converst wort to beer, it creates alcohol and carbon dioxide. Alcohol is less dense than water, so as the wort ferments and converts into beer, the specific gravity of the mixture will gradually decline. Water, as you might recall from high school chemistry class, has a specific gravity equal to 1.000 (1 gram per cubic centimeter). Unfermented wort can have a specific gravity somewhere in the 1.020 to 1.080 range, but a typical starting point is around 1.045. The specific gravity will gradually decline as the yeast converts the sugars to alcohol and carbon dioxide and when it stops dropping, the homebrewing knows that fermentation is complete.
The hydrometer’s job is to measure specific gravity, but it should not be placed directly in the wort or beer mixture. Instead, it is best to siphon off a small amount of the mixture into a tall, narrow cylinder (hydrometers come with such a cylinder, but if yours is lost, a narrow bottle will do the trick). The narrower the cylinder, the better because it means you will not waste as much beer/wort when you take your measurement. Not only that, but it will be much easier to read the hydrometer in a tall, thin, cylindrical container. It also lessens the chances for contamination.
One common mistake every homebrewer can/should avoid is checking the specific gravity too frequently. The more you check the gravity, the greater the chances for contamination because you are exposing the wort/beer mixture to the elements. One simple rule of thumb is to never bother checking the specific gravity if you can visibly see bubbles in the wort and/or in the airlock. Obviously, if the wort is still bubbling, it is still fermenting, and checking the specific gravity will be a waste of time. Take your initial specific gravity reading, pitch the yeast, attach the airlock, and don’t check the gravity again until the bubbling stops.
If you use your hydrometer sparingly and properly, you shouldn’t have any problem brewing your beer to perfection. Just remember not to place the hydrometer directly in the wort/beer and not to take excessive readings. Follow these simple steps and you will be on your way to a delicious batch of homemade beer.
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