PeteB Posted July 12, 2011 Share Posted July 12, 2011 My official status on this forum is "Advanced Member" but I am just a beginner. I only had limited experience in other distilleries before starting production in my own distillery 7 months ago. Despite having a science degree and having spent countless hours in a lab, I was becoming very frustrated with variable readings on my hydrometers when measuring the same batch. I eventually noticed liquid droplets sticking to the sides of the hydrometer stem above the liquid level. This would slightly increase the weight, incorrectly indicating higher alcohol. Even though I regularly wipe the hydrometers after use, there was still an oily film preventing liquid running off. I had to thoroughly clean with detergent to get rid of the oil film. With a bit of experimenting I found I was getting up to 0.3 ABV variation (0.6 Proof) caused by the liquid droplets. I now also lower the hydrometer carefully so it won't go much below the assumed reading, that way there is no liquid film on the glass above the meniscus. It is probably very obvious I did not attend distilling school! Are these things taught at distilling school? And here is another trap I found the hard way. When diluting spirit I was finding problems hitting the target. Someome on this forum recently said "blending is a bitch" I WAS in agreement. I know how to do the calculations so I was sure that was not the problem. Recently I added the correct amount of water, I stirred thoroughly and re-tested immediately with thermometer and clean hydrometer. The alcohol concentration was still too high which meant I needed to add more water. Did another calculation and added a small amount of water to correct. When I checked a few days later the alcohol strength was too low! Too much water added. The proof was probably correct the first time. Has anyone else found this problem? Initial enquires suggest the mixture does not stabilise for some time. I now add the calculated amount (by mass) of water and leave for a day or so. I am hitting the target dead centre. Link to comment Share on other sites More sharing options...
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