Vacuum distillation advice for a non-chemist?

[wtartar]

I'm a home-scale experimenter/dabbler in the arts of distilling liqueurs/spirits and essential oils, and right now I'm trying to see what vacuum distillation(at very low temperatures) can add to the finished product as far as taste, aroma, and color go. For my initial experiments, I've been using a simple glass set-up with a 1000ml boiling flask in a sand bath with a liebig condenser. I've been using an automotive vacuum(for brake lines, etc.) attached to the vacuum take-off valve. I've just been trying to bring ethyl alcohol(everclear) over as an experiment, but I've been having some trouble.

I'm hoping this thread can be used to troubleshoot some of the problems I've been having and/or correct some of the goofy non-chemist methods i may have been using from the start.

Right now my biggest problem is that I seem to be losing vacuum. This may be through one of the clamped connections between where the glass fits together, or it may be from the tubing connected to the vacuum take-off. Is there a good method to check for leaks or a fool-proof method for sealing connections so they can't possibly leak in the first place?

Here are some pictures:


http://s129.photobucket.com/user/erzulie_tartar/library/lab


I have been using vacuum grease with ground glass joints(+keck clamps) that fit well together, so I'm doubting that I'm losing vacuum through the actual glass connections in the set-up, although I'm still entertaining that possibility.

My thought is that I'm losing it through the tubing I've attached to the vacuum take-off. I used a flour-based paste to seal it over, but maybe that isn't the best idea? Maybe the tubing itself is too porous and I need to get higher quality tubing? Any idea as to resources to find this?

Also, if anyone wants to throw any critiques out there about the set-up I'm using(after viewing the pics), I'm all ears. I'm totally a novice and I'm sure I'm making a lot of stupid mistakes that I'm unaware of.

Thanks!

 

[Zefram]

Dear home-scale experimenter/dabbler,

Thank you for sharing your experiments with us. Vacuum distillation at low temperatures is certainly an interesting technique to explore in the world of distilling liqueurs and essential oils. I would like to offer some suggestions and troubleshooting tips to help you with your current challenges.

Firstly, it is important to make sure that your set-up is air-tight to maintain the vacuum. You can check for leaks by applying a soapy solution on the connections and looking for bubbles. Another method is to use a vacuum gauge to monitor the vacuum level and see if it is dropping unexpectedly. While vacuum grease is commonly used to seal glass joints, it is also important to make sure that the joints are clean and free of any debris that could prevent a tight seal.

In terms of the tubing connected to the vacuum take-off, it is best to use high-quality, non-porous tubing to prevent any loss of vacuum. Silicone tubing is a good option as it can withstand high temperatures and is less likely to be porous. You can find this type of tubing at scientific supply stores or online.

As for your set-up, it looks like you have a good start with a boiling flask, sand bath, and liebig condenser. However, it is important to make sure that the condenser is properly cooled to condense the vapors back into liquid form. You may also want to consider using a vacuum pump instead of an automotive vacuum for better control and stability of the vacuum.

I hope these suggestions help you troubleshoot your current challenges and improve your set-up. It is always exciting to see individuals experimenting and pushing the boundaries in their fields, and I wish you the best of luck with your vacuum distillation experiments. Happy distilling!