Comments on: Big Pimpin: My New Buchi, and the Buchi-Cooking Issues Summit

By: davearnold

davearnold — Thu, 05 May 2011 18:02:18 +0000

Howdy! I use the Polyscience chiller, which will do -20 or better. The one thing I don’t like about it is it can’t take too much back pressure on the system so you can’t chill two items in series with it. I run alcohol as low as I can. Usually, by the time you are distilling water, the amount of energy required for condensing the steam onto the coils is so large that you won’t get freezing problems unless your distillation stalls. If you start getting freezing (wich isn’t the end of the world you can raise the temp a bit and the ice will disappear real fast.

By: Matthew

Matthew — Tue, 26 Apr 2011 11:22:36 +0000

Dave,

Greetings from Munich ! We use another rotovap model at http://www.derraum.com.au but I’m thinking of buying a Buchi for a new project in Munich. What chiller would you recommend? I noticed their big chiller only goes to -10. The system we have in Melbourne ( although it’s been worked on) can achieve much lower temps but I don’t have those lab rats here at my disposal in Germany so I need to buy a commercial system. I normally cook at around 35-65 but to be honest there is a lot of guess work involved and lots of wasted stock. The results are great but there is probably a better way, what reference point do you use when determining temp and pressure for herbs and other flavouring agents? Anyway continue to love reading about your work and look forward to running into you again on the speaking circuit. All the best Matt

By: Steven in Santa Fe

Steven in Santa Fe — Fri, 03 Dec 2010 17:45:59 +0000

Hey, Dave.
Great posting. Very interesting thread. You have given me a lot of new ideas for independent, out-of -the-box ideas for extractors/evaporators.
I think Sigma-Aldrich makes an adapter that might work for your residue removal: part #Z153141. It could be inserted between the vapor tube and your evaporation vessel, and draw the residue out of the flask/beaker/jar, whatever. But you would have to stop rotation and attach a hose to the side arm drain vent to use it. And I have not looked closely enough to see if it would be compatible with a continuous feed set up.
They also make an adapter for standard jars, part #Z723169, that is very reasonably priced when compared to the $500-750 that Buchi charges for their beaker-flasks. I believe they can be used with a wide range of shapes and sizes of jars. I am just about to go and check them out. How nice to be able to finish evaporating a concoction right in its storage/sales container!
Thanks for all of your great ideas. Very inspired and inspiring. Hope you keep it up. Although I imagine you are like me, in that with this kind of creative/inventive endeavor you cannot be deterred…
With my best from sunny Santa Fe, NM
Steven

By: Merlin Griffiths

Merlin Griffiths — Fri, 06 Aug 2010 12:45:25 +0000

Dave, Sounds like things have really moved fast since Manhattan in May! Excellent news. Maybe the Buchi guys in the UK can add more fuel to your fire… Look forward to seeing you again soon in London.
BTW, on the subject of cold-finger probes, for Oxley we use Polycold to chill at -100C, LN proving too cold for our distillation process.
Best, M

By: davearnold

davearnold — Thu, 05 Aug 2010 13:17:40 +0000

Mostly Water and EtOH

By: chambe

chambe — Wed, 04 Aug 2010 19:19:22 +0000

a water aspirator is ideal for low bioling point organics like DCM or EtOAc – but it will never remove water without a significant amount of heating. i figure in the kitchen water is the only solvent you’re really looking to remove. yeeee.

By: Galen

Galen — Fri, 30 Jul 2010 16:12:15 +0000

The traditional is dry ice and acetone. Although with your near limitless supply of liquid nitrogen….

By: schinderhannes

schinderhannes — Fri, 30 Jul 2010 14:12:26 +0000

Dry ice in the cold fingers in plenty sufficient, commercial lyos cool the reciever side to -60 to -70..

4 mbar is prolly borderline but I´d give it a try.
Good luck.

By: davearnold

davearnold — Fri, 30 Jul 2010 13:44:40 +0000

Will try. Do you think dry ice is good enough for the cold finger as well? My pump gets down to 4 mbar.

By: schinderhannes

schinderhannes — Fri, 30 Jul 2010 07:43:11 +0000

Hi Dave,

it really looks like you are darn close to an ghetto lyo with this on.
You have a new and well sealing rota, you have a cold finger chiller, and you have an awesome flask for food stuff. Only thing I don´t know is how good a pump you have, but maybe the following is worth a try:

Take some clarified juice, lime, rasberry whatever. Put like 4-5 ounce into your flask.

Make a dry ice bath (a bowl large enough to put you flask in, filled with chips of dry ice and some booze.)

Rotate by hand your flask in said bath till you have a even thin layer of frozen juice on the inside. (as cold as possible, take your time.)

Put the flask on the rotavap, wrap it with aluminum foil, a layer of insulation (paper towels) and a second layer of aluminum (leave some place to peek inside….)

Pull as much vakuum as you can with coldfinger full of LN, as small a collection flask as you have (nothing will go in there anyways), no rotation and of course no waterbath.

See if the chilling by sublimation of the ice is sufficient to keep it frozen as you freeze dry.

Will take several hours….

Good luck!

If you succed you will get a layer of very light fluffy foam tasting like rasberry juice.

Put this as decoration on a nice desert and enjoy!