September 4, 2015 by fhsteinbart
About every month or so I get a customer who wants to know what the alcohol content of their wine, beer, kombucha, etc. is. So I usually ask what their original (OG) and terminal (TG) gravity readings were from their hydrometer. Usually what happens is that they either forgot to take a reading, or their hydrometer was broken at the time. Well, no fear folks, science has come to your rescue! You can actually determine your own alcohol by volume or weight (ABV/ABW) by using some good old fashioned high school chemistry items like a 250ml Erlenmeyer flask, 5~10ml burette, 5ml beaker or glass vials, 1ml and 10ml pipettes, (which we sell at FHS), sample to be tested, and optionally a heat source such as an incubator, or even your oven (set to 200°) can be used! Then you’ll need a few chemicals (like potassium dichromate, potassium iodide, and sodium thiosulfate) that you can obtain from Nurnberg Scientific. This process takes time, and may require and overnight hiatus to completely react all the ethanol with the dichromate. While this does involve some basic algebraic math, it still will give you an accurate assessment of the total amount of ethanol to a high degree of accuracy.