A hydrometer is perhaps THE most important piece of brewing kit you'll ever own, yet some homebrewers never even use them. \n\n\n\nIt's the measurement device that 99% of all your post-fermentation calculations are based on, so having an accurate tool is really important.\n\n\n\nA hydrometer's accuracy relies on calibration, temperature, its correct usage, and lack of damage to the instrument. Taking a reading from the correct place on the scale and in wort free of obstructions or solid matter increases accuracy. A poorly disolved wort sample or unsuitable measurement jar is also a factor.\n\n\n\nAs there is a little bit to know concerning this topic, I've gone into even more detail in the rest of this article so please feel free to read on.\n\n\n\nHow does a hydrometer actually work?\n\n\n\nAll variants of hydrometers, incorporate the physical law of buoyancy (Archimedes' principle) where a solid object displaces its weight in liquid. Saccharometers, used in homebrewing, measure sugar content in wort and are calibrated to 1.000 in distilled water. The specific gravity is shown on the scale at the surface of the wort.\n\n\n\nAll hydrometers have a similar design. They are long with a thinner arm, where the scale is shown, and a bulbous bottom which contains metal shot as a counterweight.\n\n\n\nWhen immersed in enough water, they float and by displacing their own weight they will show the specific gravity of the wort they are in.\n\n\n\nAs long as they read 1.000 in distilled water they will be accurate when placed in sugary wort.\n\n\n\n\nhttps:\/\/youtu.be\/GCyqBNV6u48\n\n\n\n\nWhat can affect a hydrometer reading?\n\n\n\n\n\n\n\nIn terms of why a hydrometer will show a reading of above 1.000, it's simply due to the amount of sugar dissolved in the wort it is placed in. \n\n\n\nThe more sugar present in your wort, the higher your specific gravity will go. \n\n\n\nAfter fermentation, that sugar is digested by yeast and so your final specific gravity reading (final gravity) will be lower than the initial reading (original gravity).\n\n\n\nTalking of what can make your hydrometer inaccurate, well there are a few things to consider.\n\n\n\nA hydrometer will be inaccurate if it or the measurement jar is dirty, has a lot of organic matter in it, or bubbles present. Also, if sugar in the wort hasn't dissolved enough or been blended well the reading will be off. The temperature of the wort also affects the reading, which should always be taken from below the meniscus.\n\n\n\nWhat does that mean in less robotic language? Well let's go over those point in more detail.\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n Plan your next Beer Creation?