I’m struggling (again) to make sense of my Hydrometer. I am brewing an American IPA from a kit. I started on Sunday and before pitching the yeast I took a reading (photo 1), I had 24 hours crazy fermentation, then nothing. Barely a bubble. Today (Thursday - Day 4) I took anther reading (photo 2). Something has definitely happened and it floats a lot lower! I am meant to be adding hops on day 7 and tasting it on day 10. Am I on track with this reading?

Also, sorry for the really basic question, but why does my potential alcohol scale on my hydrometer appear to go in reverse I.e it started at 6% and is now nearer 0% after fermentation?


Original reading

Day 4 reading


I'm not sure how to answer your first question, but I can answer your second question. A hydrometer doesn't measure potential alcohol; that's something we as the user derive from the information. What the hydrometer does do is measure the gravity (density) of the wort. Starting at 1.000 is water, but because sugar is heavier than water, any added sugar raises the density. A hydrometer allows us to quantify how much change in density has occurred, thus telling us how much alcohol has been made and sugar consumed by the yeast. That is why your hydrometer scale appears to go in reverse, because the yeast are making the liquid less dense through consumption of sugar and producing an alcoholic solution.

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  • Aha! I understand now. So my orignal reading had. a reading of 7% and my latest reading is about 1% so my alcohol content is approx 6% (plus or minus the alteration made for temperature etc.)? Thank you for explaining that. – Andrew F Oct 15 at 19:55

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