r/ChemicalEngineering • u/[deleted] • 1d ago

Chemistry Distillation of alcohol beverage not working.

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For context, I’m a chemical engineering student currently taking organic chemistry, and my group recently performed a distillation of an alcoholic beverage (wine, ~15 mL sample). We used a small distilling flask, a vertical column, a thermometer at the head, and a condenser connected through an adaptor (the connector between the column and condenser, which I’ll call #2). Cooling water was run at a moderate rate (bottom-in, top-out), we added boiling chips, and greased all joints to prevent vapor leaks. At the start, we observed a short forerun of 2–3 drops, during which adaptor #2 became hot and the thermometer climbed to about ~70 °C. But after that, the adaptor suddenly cooled down drastically, the thermometer reading dropped, and no further ethanol distillate came over, even though the column itself stayed hot. This confused us because we expected that if the column was hot, vapors should have continued into the adaptor and condenser (with ethanol boiling around 78 °C). Could this cooling be due to premature condensation inside the column before the vapor reached the head, or does this suggest an issue with the adaptor itself? I’d appreciate any insights on why this happened and what adjustments (heat input, condenser water rate, etc.) we should try to maintain a steady ethanol distillation. (Attached is our set up)

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u/ChemSciGuy 1d ago

Use more wine. Starting with only 15 mL means you will get 1.5 mL if you had an ABV of 10%. Your glassware has too much surface area for such a small volume of distillate.

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u/Ok_Path8613 1d ago

This. 15 ml wine is roughly 1,5 ml ethanol. Depending on the setup not enough to even fill the columb completely with vapor.

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u/SauceyMerchant 1d ago

Agreed with the above comments. One thing to add is to consider making the column shorter. One lesson learned from hobby distilling is you want just a little more head space (20-30%) than what is necessary to keep from boiling over. Extra unnecessary space will ultimately mess with your yield towards the end.

Make fine, slow temp increases as you approach the BP of water. I only increase the temp by a degree once I stop seeing distillate. It's a long and slow process, but if the goal is to have something potable at a significant yield that's what it takes.

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u/_Estimated_Prophet_ 1d ago

This is the answer