When you remove the daily post from your mailbox, how often do you find a catalog chock full of shiny new homebrewing toys? Anywhere from four to six of these arrive at my house per month, and although the products remain mostly the same from one issue to the next, I never fail to browse the whole thing cover to cover every time. The siren’s song of new gadgets is simply too beautiful to ignore.
I managed to ignore the refractometer for a long time. After all, a hydrometer is much cheaper and measures wort specific gravity just as well. But refractometers do offer some nice advantages. Only a small wort sample is needed, a couple of drops rather than a test tube’s worth. A refractometer won’t roll off the counter and onto the floor, shattering into countless shards of glass. Also they look cool.
The refractometer operates on the optical principle that light passing through a liquid refracts at different angles according to the density of that liquid. Rephrasing that statement, light passing through a small sample of wort refracts at different angles according to the concentration of dissolved sugar in that wort. The refracted light illuminates a scale, upon which is printed a range of wort densities. You peek through an eyepiece and read the wort density from the scale.