Rotary evaporator

[Kent Wang]

This article from the French Culinary Institute goes into detail about the rotary evaporator that they have.

Highlights:

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We use the rotovap for two main purposes: 1) to concentrate non-volatile components in a mixture (for example, concentrating the purest and freshest flavors from a blood orange by removing the water), and 2) to extract the volatile aroma and flavor molecules from mixtures gently and at low temperatures (for example, extracting the desired flavors from a blend of alcohol, herbs, and fruit without heating the mixture up).

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In January 2006 I went to Madrid Fusion and saw Joan and Jordi Roca do a demo with their rotary evaporator. Those guys are great. I knew some chefs had rotovaps but this was the first time I had ever seen a chef demo one. I was amazed by how quiet it was (even our current model is loud because of all the pumps we have running). One of the dishes they demoed rotovapped dirt from their local forest into a clear, dirt-scented water that they put on oysters—surf and turf with literal local terroir. Very poetic.

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If you had to buy my rotovap using all new parts you’d end up spending $18,000. Ouch. Even so, I love the rotovap. It is my favorite piece of kitchen equipment. It allows me to create flavors that would otherwise be impossible.

An initial question I have is that for doing something fairly simple like reducing pomegranate juice to make grenadine, could I just put the juice in a pan and put it in a food dehydrator, which is much cheaper? How about stock?

Sure, you would lose some of the aromatics, while the rotary evaporator, based on my cursory understanding, would capture all of it. But that's a compromise I'm willing to make. I could see something like making brandy and syrup from wine (as detailed towards of the bottom of the above article) to absolutely require a rotovap.

Edited April 16, 2016 by Smithy
Added tag (log)

[Kerry Beal]

A new toy to add to my jury rigged vacuum microwave and my new to me still! I guess I could just collect the liquid that is vacuumed off from what I'm heating in the microwave - might save the need for another purchase.

I think your idea for reducing the pom juice would probably work well and not boiling would be good, but I think they are collecting the distillate rather than using what's left in the heated part.

[slkinsey]

You're still heating the liquid, you're just not heating it as much. And you're able to more accurately capture either what's driven off or what's left behind.

A similar process (vacuum reduction) is what's used to make most commercially-available concentrates. It's cheaper and faster to do it that way. This is why, for example, tomato paste still tastes somewhat "raw." That's because it hasn't been heated to a very high temperature. Similarly, commercial pomegranate juice concentrates were not concentrated by boiling at 100C, they were reduced under vacuum (juices "from concentrate" were simply made by adding back some of the water).

[sygyzy]

I wish there was a way a home cook could get a Rotovap. Is a distiller similar? I want to be able to make my own extracts for cooking.

[Tri2Cook]

I wish there was a way a home cook could get a Rotovap. Is a distiller similar? I want to be able to make my own extracts for cooking.

There is... if you have $10,000 laying around looking for something to do.

[Kerry Beal]

I wish there was a way a home cook could get a Rotovap. Is a distiller similar? I want to be able to make my own extracts for cooking.

Lots on e-bay, just look up rotary evaporator or Buchi. Quite reasonably priced.

They aren't like a regular still because of the vacuum, which allows them to do their thing at a much lower temperature than a classic still. So less change in volatile flavours due to heat.

[Kent Wang]

I wonder if liquor distilleries would have a use for this.

[sygyzy]

I wish there was a way a home cook could get a Rotovap. Is a distiller similar? I want to be able to make my own extracts for cooking.

Lots on e-bay, just look up rotary evaporator or Buchi. Quite reasonably priced.

They aren't like a regular still because of the vacuum, which allows them to do their thing at a much lower temperature than a classic still. So less change in volatile flavours due to heat.

Would my idea work? Could you use a rotovap to distill herbs or other foodstuffs into concentrates?

[paulraphael]

I wonder if liquor distilleries would have a use for this.

I hope some will play with it. The possibilities are interesting. The resulting liquors might taste especially fresh and three-dimensional. And all kinds of interesting things might be done with the stuff left behind, sinci it won't be deadened by boiling.

[MelissaH]

I wonder if liquor distilleries would have a use for this.

I hope some will play with it. The possibilities are interesting. The resulting liquors might taste especially fresh and three-dimensional. And all kinds of interesting things might be done with the stuff left behind, sinci it won't be deadened by boiling.

But, technically, it is boiling. You're just reducing the atmospheric pressure inside the vessel so you don't have to heat it as much to get to the point where the vapor pressure is equal to the atmospheric pressure. Anything volatile will still come off; presumably, it'll be captured in the solvent reservoir unless it's so volatile that it gets sucked right down the drain or into your vacuum pump.

MelissaH

[Kerry Beal]

I wish there was a way a home cook could get a Rotovap. Is a distiller similar? I want to be able to make my own extracts for cooking.

Lots on e-bay, just look up rotary evaporator or Buchi. Quite reasonably priced.

They aren't like a regular still because of the vacuum, which allows them to do their thing at a much lower temperature than a classic still. So less change in volatile flavours due to heat.

Would my idea work? Could you use a rotovap to distill herbs or other foodstuffs into concentrates?

Yup, I think it would, there would be the distillate - which is the essential oil component of the herb and what ever is left behind in the flask which would be a concentrate of that part.

[paulraphael]

But, technically, it is boiling.

shoulda said: won't be deadened by cooking.

the issue is chemical reactions from the heat, not the phyical state change.

Edited October 16, 2009 by paulraphael (log)

[jk1002]

I am playing with it. I sampled some of the liquors at the FCI during a cocktail class. I recreated their Habanero Vodka and Peanut Brandy.

Obviously I am not using a rotovap but a distillation kit from a lab supply store. Its not as effective but still does the trick.

You could exract herbs into a neutral booze, I don't think you can use it to concentrate. For one as not all flavor compounds will distill you alter the taste. For two, after making peanut brandy I tasted the residue peanut base and it tasted horrible. I would think the same applies to herbs. When you distill wine into brandy it is supposed to work - leaving you with a yummy syrup but I haven't tried that yet.

What got me hooked was the Habanero Vodka ..... the compound in the Habanero doesn't distill so you get a very intense Habanero Taste and smell without the spicyness. Is a very nice party gimmicky shot - haven't figured out how to combine that into a dish but am pretty sure it's possible.

I looked at the Rotovaps on ebay, mostly they miss key parts like the glasware and the vacuum pump which are expensive. Complete rotovaps are somewhat expensive even on ebay.

Cheers

JK

Edited October 21, 2009 by jk1002 (log)

[Pierogi]

OK. Just as a heads up/word to the wise here.

I work for a scientific supply house that sells rotovaps and all the supporting equipment/flasks/controllers/tubing etc.

I work in the compliance area, and my current project is researching how indivual States control so-called "drug apparatus".

Currently, the Feds don't control stuff like this. Any Tom, Dick or Harry can order it without any worries about the Feds sniffing around.

The story is, however, very different in many States. My project isn't complete, and I can't speak for every State, but I do know, FOR ABSOLUTE CERTAIN, that in some States (California for example) this type of equipment is definately controlled as "drug manufacturing apparatus" that can be used to cook meth, crack, PCP and all sorts of other nasties. The definitions of "drug manufacturing apparatus" are deliberately vague. It can include things like "flasks", "tubing", "controllers", "condensers" and "extractors".

Not to say you won't be able to buy this sort of stuff from scientific supply houses, and you probably can score it easily from Ebay, but.....

If you are going to try to buy it from scientific supply houses be prepared for some very pointed questions, and the possibility that if you are not affiliated with a licensed business, they will not sell to you.

If you are trying to buy from Ebay or from another on-line auction/private reseller, be prepared that you may be dealing with an undercover narc.

FYI, I've worked in Regulatory Compliance for about 30 years. I know my stuff, and I know how to read regulations and statutes.

Just sayin'.

[jk1002]

Interesting.

In europe you can find rotovaps already in some restaurant supply stores.

http://www.willequipped.com/rotoVap.html

For US, at the link above. Note the 10K price tag. I just checked ebay, there are a few core systems for under 200$ but the glas bottles and vacuum pump and water bath are quite expensive and the core system doesn't come with that.

Also note that for the FCI applications they modified the rotovap to get better results.

I just don't see this beeing used outside molecular restaurants or as you say, drug manufacturing operations.

Cheers

JK

[sygyzy]

What's interesting is Will Godfarb is an American chef so I don't know if that site is really European, or if it is, why?

I looked briefly into getting a RotoVap used on eBay but soon was overwhelmed with information. I don't really know what a complete RotoVap is supposed to look like, what parts it's supposed to have, and how easy it is to replace missing parts. So while I saw some deals, I didn't make any bids because what might have seemed like a deal at $600 may have needed $1500 worth of parts and I wasn't ready for that.

[jk1002]

What you mention about the 600$ deal is exactly the point. I am guessing over time you could score a complete Buchi on Ebay but that takes patience and some luck ...

http://www.cuisinetechnology.com/RotaryEvaporator.html

Polyscience is selling a rotovap for the kitchen as well. I think the drug posting should be taken seriously but times change and it should be fine for a restaurant to buy one.

For the home, as with all Ebay used lab supplies, who knows what they did with it, I am not touching that stuff and my simple distilling setup works OK for the flavored booze the FCI guys are producing.

The thought of creating herb essence is intriguing not sure though how that would work without using alcohol.

[MelissaH]

What are people using as their vacuum source with their rotovaps? I've used both aspirators and water pumps in lab, and don't see either as ideal in a kitchen setting. (Not to mention the other little issue of needing to somehow cool the condenser.)

MelissaH

[Montreal]

I understand that a Rotary Evaporator can distill.

Anyone out there can give me some concrete example on how a Rotary Evaporator can be used creatively in a kitchen.

It is a lot of money and I would love to have some example of what you might have accomplish with this that makes your experience worth it.

Sometimes just the fact that we can create something impossible to duplicate any other way is the trigger point.

Anyone out there that have one and is willing to share their experience

Tks

Edited November 17, 2010 by Montreal (log)

[Teddy Devico]

take japanero and distil out the actual fruty flavor of the pepper and leave behind the crazy heat. The flavor of the pepper without the heat is extraordinary.

[Chris Hennes]

If you haven't already, make sure you check out the Rotary Evaporation Primer over at the Cooking Issues blog. Dave, Nils and Co. do a fantastic job of convincing people they need this sort of thing .

[Montreal]

Thank you so much this is exactly what I was looking for

[jk1002]

I would probably start with a normal distillation kit for hu dred or 200 bucks from a lab supply store ... The jalapeno vodka one gets done with it, other things as well.

Obviously you could not scale this up to be used commercially but most of the rotovap applications that have been demoed here and there are illegal at this point anyhow.

[Montreal]

Interesting point. So far, I have to admit that most use has been limited to create some kind of illegal or short live product by deconstrcuting / seperating / extracting from one food and re adding it up to( something else) to create something more powerfull or more pronounce.

I am looking into creating essence from different ether in order to add aroma rather than taste or texture to some of the food.

For example.. Can I somehow create( in liquid form ) the smell of fresh loaf of bread and add this to a SV bag while I cook a steak so that when you eat your steak you have the impression of having a fresh loaf of bread right beside you when in fact it does not really exist anywhere but in your imagination because of the aroma that was added to your steak.

Okay, okay... I am probably getting carried away, but I believe that looking into my dream is the only way to be ultimately challenge to progress.

If if ever get there, I will let you know

[pbleic]

It isn't necessary to pay $10,000 for a rotary evaporator. The Yamato RE-200-1-A Rotary Evaporator is sold at many places on the web for ~$2,400 (diagonal condensing tube) or ~$2,900 for a vertical condensing tube which looks and works exactly like the $10,000 variety from Polyscience. It will be one that holds substantially smaller volumes, but has a continuous feed inlet for adding more starting liquid. The setup requires a vacuum pump capable of 30 CFH, and there are many with 6 times that capacity that can be purchased for $100.

$2,500 to $3,000 is still quite expensive for the home cook, but could put this capability in the hands of more restaurants.