Importance of Temperature in Hydrometer Use

Hydrometers (also referred to as refractometers or alcohol meters) are indispensable tools for brewers. With them, brewers can quickly determine their wort’s sugar content, monitor fermentation processes and estimate how much alcohol will end up in their final product using simple mathematics. Furthermore, hydrometers allow brewers to monitor yeast health during fermentation by showing how much of their wort is being converted to alcohol during this process.

A standard floating hydrometer consists of a narrow vertical tube equipped with one or more scales to produce numeric readings, and a weighted float which sits atop a glass bulb at its bottom end. As liquid density decreases, its density impacts how much the float sinks; once liquid meets with this intersection point at the top of the float it is taken as indication of specific gravity of that sample.

Temperature fluctuations of wort or beer being tested can have an impactful impact on hydrometer readings, yet this is easily corrected for. Simply keep track of expected sample temperature as specified on your hydrometer and utilize either its manufacturer-supplied correction table or an online calculator to adjust readings accordingly.

Before conducting measurements, it’s crucial to ensure your hydrometer, jar and sample have all been appropriately sanitized. This involves drying out any surface moisture inside of a jar completely before taking measurements as well as clearing away debris or bubbles from its float surface in order to avoid false readings. Twirling an instrument before reading it may help disperse trapped gases more evenly for more accurate results.