Hydrometer
If you are new to home distilling, you may encounter the term “hydrometer” often. A hydrometer is a device used to measure the density of a liquid, which is an essential component in determining the alcohol level in a fermenting mash. Here’s a comprehensive glossary of terms related to hydrometers and home distilling:
What is a Hydrometer?
A tool used to measure the specific gravity or density of liquids. In home distilling, it is primarily used to measure the alcohol content of a brew.
You’ll need to use a hydrometer with a hydrometer jar. This combo pack on Amazon is perfect.
Specific Gravity
The relative density of a liquid compared to water. It is expressed as a ratio, and hydrometers measure it in degrees, usually abbreviated as SG.
Alcohol by Volume (ABV)
The amount of alcohol present in a liquid as a percentage of the total volume. For brewers and distillers, a hydrometer can determine the ABV of a fermented mixture.
Original Gravity (OG)
The specific gravity of the wort or mash before fermentation. This will give the brewer or distiller an idea of the potential alcohol that can be made in their product.
Final Gravity (FG)
The specific gravity of the cooled and fermented liquid. By comparing the OG and FG using a hydrometer, one can determine the ABV and know when to stop the fermentation process.
How to use a hydrometer
Here’s a step-by-step guide on how to use a hydrometer:
- Buy a spirit hydrometer and testing jar. This is exactly what you need. If you buy the Air Still companion pack, it also comes with both.
- Obtain a sample of your brew: Use a sterilised syringe or jar to extract a sample from your fermentation vessel.
- Pour the sample into a hydrometer test jar: Make sure not to overfill the jar – you need displacement space for the hydrometer.
- Take the initial reading: Carefully place your hydrometer into the jar until it floats freely without touching the bottom or sides. Spin the hydrometer to displace any air bubbles.
- Take note of the reading at the meniscus, which is the curved line at the surface of the liquid. In this step, you’re measuring the specific gravity (SG) of your brew before fermentation. This is called the original gravity (OG).
- Ferment your wash!
- Subtract the final reading from the initial reading: After fermentation, but before distillation, take another reading of the liquid in the hydrometer jar using the same method. This time, you’re measuring the specific gravity after fermentation – the final gravity (FG).
- Calculating the alcohol percentage: Subtract the final reading from the initial reading to find the change in specific gravity. Then, use an online alcohol percentage calculator to convert that change in specific gravity to an alcohol percentage.
By following these steps, you can accurately measure the alcohol content of your home-distilled drinks with a hydrometer.
Fermentation
The process by which yeast converts sugars in a mash or wort into alcohol and carbon dioxide.
Yeast
A single-celled fungus that converts sugar into alcohol and carbon dioxide during fermentation. There are various types of yeast used in home distilling that produce different flavors, aromas, and alcohol levels.
See: best yeasts for air stills
Air Still
A compact distillation unit that uses a circulatory system to distill fermented mixture. It’s designed for home distillers who want to distill small amounts of alcohol.
See: best air still for making alcohol at home
Whether you’re a beginner or an experienced distiller, a hydrometer is an essential tool to ensure the quality and consistency of your final product. So, get your hydrometer and start your home distilling journey today!