patent-pending vacuum distillation and infusion still

[Thatch]

I'm not generally impressed when I visit distilleries but low and behold what I found in Ohio farm country East of Cleveland.  Although the inventor was not present, I believe these are back to back continuous column vacuum stills.  Both seem to have infusion abilities.  His nephew told me that the inventor built his first still at age 12.  There are a couple of additional photos on their FB page.  I have no additional information.   https://www.facebook.com/SevenBrothersDistillingCo/

[Foreshot]

Bad link

[Thatch]

16 minutes ago, Foreshot said:

Bad link

Worked for me.  Go to their FB page and click on photos

[Silk City Distillers]

Was really excited by vacuum distillation for a while.  I still rotovap nearly everything when I get a free minute to do it.  But, I think people put vacuum distillation up on some kind of pedestal as a pinnacle of distilling engineering, when it's really not the case.  Vacuum distillation is just a tool, not necessarily better or worse than atmospheric distillation, just different.  It's like the difference between SAE and Metric sockets, flat vs Phillips screwdrivers.  They aren't so different, but why you might use one or the other certainly is different.

Better to think of it as low pressure distillation, it's a continuum, from very low pressures to very high pressures.  The pressure you would use in your low-pressure distillation would be based on what you are trying to accomplish by reducing the pressure.  It becomes a little less magic when you realize it's still the exact same process, you are just varying the pressure of the process.

The single biggest benefit for us, as beverage distillers, is the potential to reduce thermal decomposition of temperature sensitive compounds.  It's the reason I still like using the rotovap to extract botanicals.  Reduce the pressure, reduce the boiling point, reduce the vapor temperature, and reduce the impact of thermal decomposition - but only if what you are distilling is temperature sensitive. 

Also keep in mind that thermal decomposition isn't discriminate.  It's just as probable that decomposition impacts bad flavors as well as good ones.  So don't automatically jump to the assumption that by distilling in a vacuum, you get a better tasting product.  Yes, for the most part, when distilling botanicals, you get a "Truer" extract.  But it's not always the case, and it certainly isn't the case when distilling from a fermented wash (as opposed to running straight solvent extracts with neutral alcohol).  Also keep in mind thermal decomposition is a factor of temperature and time.  Which is the reason that most vacuum distillations are not carried out under periods of long reflux.  Good example of this is the short-path distillation technique - the goal being the reduce the time under temperature as well.  (Realize this means no columns, no plates).

The other factor when it comes to temperature, is that higher temperatures aren't necessarily bad.  Consider the fact that under the kinds of distillations we do, they are not straight/pure separations, but are reactive distillations.  We are creating new compounds as part of the distillation process, and a major factor of that is heat.  You can find lots of examples of products that utilize flame-heated stills in a very beneficial way, Maillard products, etc etc.  Esterification of acids in a column or thumpers.  Too much to dive in to here, just keep in mind that temperature isn't bad.

Take those two factors together, and you can see how it's not necessarily a better/worse process anymore, but different.

Now, also consider the fact that as your reduce pressure, vapor speed in the column begins to increase significantly.  Column diameter needs to increase significantly to compensate for the high vapor speed.  Plates begin to become less effective, because the higher differential pressures make it difficult for reflux to drain through the downcomers.  Typically why you only see packed columns used for low-pressure distillations.  I'll post the math once I have some time to show it, but you end up in a situation where the vapor speeds are so high that entrainment and flooding become major issues.  You begin to require some fairly massively sized columns to reduce vapor speed. 

As you reduce pressure, control issues start to become big problems.  Bumping, surging, stability of vacuum control, etc.  The lower the pressure, the faster and easier it is to upset the system.  For example, completely vaporizing all the held-up liquid in the column, puking up the boiler contents through the column in about 1 second time.  As you reduce pressure, the equipment begins to get very expensive as the design pressures and material thicknesses increase.  It's fairly easy to spend a small fortune building a system that has absolutely zero benefit over an atmospheric system.

Love it for gin, I rotovap gin components all the time.  You want a beautiful cucumber flavor?  Vacuum distillation all the way.  Sorry, but distilling cucumber at atmospheric, the end result is stewed sh!t in comparison.  You want to emphasize light, delicate aromas?  Flowers?  Totally.  Love big gin?  Don't bother, heavy flavors act like a sledgehammer to your taste buds, you'll never taste the difference.  Solvent extractions of botanicals are where low-pressure distillation really shines.

Want to talk really low pressure distillation?  I have the dry ice bath condenser for my Buchi.  I can run acetone and dry ice in the condenser at about -70c.  I've got a pretty wicked three stage lab pump that can pull single digit torr, and a really good vacuum controller than can hold it there without disaster.  I've done botanical extractions as low as 10 torr.  That's boiling at room temperature.  No water bath at all, just heated by the air in the room.  Just breathing on the boiling flask is enough to almost make it surge out.  Super cool stuff, being able to extract the aroma of a flower at a temperature no greater than it would see on a warm spring day.  I can distill even cooler, but it's a pain in the ass, since you need to cool the boiling flask, immerse it in cool water, and hope it doesn't warm up faster than you can finish the distillation.  Sound awesome?  Yeah, it makes great marketing, but really, the end result even distilled warmer is the same.  Wah wah.

As much as I love this stuff, I've played around with it to know that it's just a tool, not better, not worse, but can certainly yield a product better, or worse, depending on the situation.

Can you rebuild a european motor using only SAE tools?  Maybe, but it's going to suck.

[Southernhighlander]

 We already have vacuum stills for sale if anyone is interested, including the flavor infusers, except ours are a lot prettier than 7 brothers. Except for our vacuum stripping stills and vacuum stills for hemp to CDB processing and our short path vac stills and our glass laboratory vac stills, they look just like our regular stills.  In fact we have a design for a unit that is contained in a case that looks like and oversized computer tower that will connect to any stills parrot connection so that it becomes a vacuum still. Our first model 5-150 is good for stills up to 150 gallon.  Our 2nd model 200-800 will be good for stills up to 800 gallons. 

Unlike some other vacuum stills we have a continuous output from the still.  We are able to do this without breaking vacuum.  This allows the cuts to be made using smell and taste.

Vacuum beverage ethanol distillation has advantages and disadvantages.  One of the disadvantages is that copper vapor interaction is reduced under vacuum.  If you pull -29.5 inHg gauge so that you are distilling at around 80 F then you will get very little sulfur removal.  At least this is what our lab tests showed.  If we pull enough vacuum to distill at around 150 F and we increased the amount of copper surface area inside the still by a certain percentage, we are able to get the same amount of sulfur removal as running under no vacuum.  Another disadvantage is that you need more chilling capacity for the condensers.  If you are distilling at -29.5 inHg gauge then the temp of the coolant going into your condensers must be -20 to -30 C.  Distilling at 122 F (50 C) means your incoming coolant temp must be at least as low as 10 C.  If you distill at 150F under vacuum then a standard chiller can be used.  Well water can be used if it is below 55F when distilling at 155F

The advantages of vacuum distilling are many.  Higher proofs with less column.  Hot water can be used to great advantage as a heat source so you don't need to buy that expensive steam boiler.  A 100 gallon commercial hot water heater can be used to heat a 100 gallon vacuum still.  Less heating BTUs are needed.  Our lab tests showed that we were getting up to 90% less methanol under vacuum, so the heads cuts are smaller.  We had faster run times as well.  There are other advantages including spirit flavor improvements due to less volatilizations of positive flavor compounds.  In my opinion flavor infusions come off better as well.

   Continuous column vacuum stills have been around for over 100 years.  Below is a picture of a really huge industrial one.  Any of our vacuum stills can be set up for continuous feed and our vacuum stripping stills are really fast.

[Silk City Distillers]

By the way, looking at the photos, I don't see what in that would be eligible for patent protection, looks like a fairly typical vacuum setup.  There is a tremendous amount of prior art in this area.

If you think you've come up with something brand new, the flavor and fragrance crew probably did it 50 years ago.

 

[Southernhighlander]

4 minutes ago, Silk City Distillers said:

By the way, looking at the photos, I don't see what in that would be eligible for patent protection, looks like a fairly typical vacuum setup.  There is a tremendous amount of prior art in this area.

If you think you've come up with something brand new, the flavor and fragrance crew probably did it 50 years ago.

 

I agree.

 

[Southernhighlander]

6 hours ago, Silk City Distillers said:

 

Now, also consider the fact that as your reduce pressure, vapor speed in the column begins to increase significantly.  Column diameter needs to increase significantly to compensate for the high vapor speed.  Plates begin to become less effective, because the higher differential pressures make it difficult for reflux to drain through the downcomers.  Typically why you only see packed columns used for low-pressure distillations.  I'll post the math once I have some time to show it, but you end up in a situation where the vapor speeds are so high that entrainment and flooding become major issues.  You begin to require some fairly massively sized columns to reduce vapor speed. 

As you reduce pressure, control issues start to become big problems.  Bumping, surging, stability of vacuum control, etc.  The lower the pressure, the faster and easier it is to upset the system.  For example, completely vaporizing all the held-up liquid in the column, puking up the boiler contents through the column in about 1 second time.  As you reduce pressure, the equipment begins to get very expensive as the design pressures and material thicknesses increase.  It's fairly easy to spend a small fortune building a system that has absolutely zero benefit over an atmospheric system.

 

We do not have flooding/puking issues in our beverage ethanol vacuum stills because we are only pulling enough vacuum to distill at 150F.  Also because of this our column functionality is preserved.  Also our beverage ethanol vacuum stills are inexpensive when compared to most of our competitors stills that operate at 1 atmosphere.

Our vacuum stills that operate at higher vacuum for producing CBD and other cannabinoids are also inexpensive.  In fact our  solvent reclamation vac stills are as little as 1/10th the cost of our competitors equipment and our quality is better.  Equipment to create cannabis concentrates such as CBD are massively over priced, with some equipment being sold for as much as 2000% over production costs.  I am already taking advantage of this, in a huge way.  The growth curve in our business is incredible right now but we are dealing with it with very good results.

  We have gotten the run times on our high vacuum, solvent reclamation stills down to 1 hr.  When we started the run times were 6.5 hrs.  This really fast distillation does cause some bumping and surging and the still pot will shake a little, however we have never had to bolt our prototypes to the floor.  We state that the ones that we sell must be bolted to the floor.  I don't think they will walk or anything but better safe than sorry. 

 We had some puking issues with our high vacuum stills during the original design phase and that is absolutely unacceptable for a solvent reclaim still but I solved that issue right away.  The newest ones are set up like short paths with no columns and we have zero puking issues.  The ethanol in the reclaim tank is free of any oils.  Also with our new semi short path design we are staying above 188 proof for 10 to 15 runs re using the same solvent which starts at slightly above 190 proof. 

Edited August 4, 2019 by Southernhighlander

[bluestar]

This is a great discussion, really provides excellent overview of pros/cons and underlying process of a vacuum distillation for spirit production! Kudos to @Silk City Distillers and @Southernhighlander for taking the time to do so...

[Southernhighlander]

One of the great things about vacuum stills is that they can be wood fired by a hydronic boiler.  Hydronic hot water boilers are relatively inexpensive to buy compared to steam boilers.  Also wood waste costs a great deal less than nat gas in many areas.  Here you can buy a 17 yard dump truck load of end trim blocks from railroad ties and pallet squares that are 80% oak for $160.00 I have my own dump truck so it costs me around $75.00 per 17 cubic yard  load from sawmills.  Also these boilers go outdoors which can make things easier concerning compliance.  Of course they are not allowed in some areas.

 I applied for and received a government grant to help pay for my last hydronic boiler which I used to fire one of my lumber drying kilns.  The government considers wood a renewable resource, which is how I got the grant.

https://earthoutdoorfurnaces.com/

[seventh son]

On 8/3/2019 at 5:42 PM, Thatch said:

I'm not generally impressed when I visit distilleries but low and behold what I found in Ohio farm country East of Cleveland.  Although the inventor was not present, I believe these are back to back continuous column vacuum stills.  Both seem to have infusion abilities.  His nephew told me that the inventor built his first still at age 12.  There are a couple of additional photos on their FB page.  I have no additional information.   https://www.facebook.com/SevenBrothersDistillingCo/

Thanks for the praise and sorry that I missed you, but my walleye fishing expedition went much longer than planned, so I was late to our open-house! My nephew was a little off, my first attempt at making alcohol was at the age of 13, but I didn't build my first vacuum still until a dozen years ago!

The equipment pics on our website and FB page are not current. I just finished an upgrade. I do have a continuous vacuum stripping still and batch vacuum stills for finishing and infusion. All designed and built in-house from sourced or locally fabricated components. 

[seventh son]

On 8/4/2019 at 11:12 AM, Silk City Distillers said:

 Vacuum distillation is just a tool, not necessarily better or worse than atmospheric distillation, just different.

As the founder of Seven Brothers and a guy who has been building and using small scale vacuum stills commercially for a decade, I agree that it is just different. Vacuum stills will allow you to manipulate variables to achieve different results. That has always been my goal, not to make a vodka just like the big guys make, but to make products that stand out as different from the herd. Ultimately, the consumer decides if they are better or worse than products made in conventional stills!

As far as running a vacuum still goes, they can be temperamental and they are not always as efficient as conventional stills. Mine are set up to sample without breaking vacuum, but making correct cuts is more challenging because the boiling point of each component changes under vacuum and you don't have traditional temperature benchmarks to rely on. It's not the easy way to make spirits.

On 8/4/2019 at 11:26 AM, Southernhighlander said:

In fact we have a design for a unit that is contained in a case that looks like and oversized computer tower that will connect to any stills parrot connection so that it becomes a vacuum still.

Southernhighlander, I have some experience imploding non-vacuum-rated vessels. It's relatively easy to convert a large, shiny, expensive still into a crumpled mass. I wouldn't pull even a modest vacuum on any vessel that is not engineered for it (again). 

[Southernhighlander]

2 minutes ago, seventh son said:

As the founder of Seven Brothers and a guy who has been building and using small scale vacuum stills commercially for a decade, I agree that it is just different. Vacuum stills will allow you to manipulate variables to achieve different results. That has always been my goal, not to make a vodka just like the big guys make, but to make products that stand out as different from the herd. Ultimately, the consumer decides if they are better or worse than products made in conventional stills!

As far as running a vacuum still goes, they can be temperamental and they are not always as efficient as conventional stills. Mine are set up to sample without breaking vacuum, but making correct cuts is more challenging because the boiling point of each component changes under vacuum and you don't have traditional temperature benchmarks to rely on. It's not the easy way to make spirits.

Southernhighlander, I have some experience imploding non-vacuum-rated vessels. It's relatively easy to convert a large, shiny, expensive still into a crumpled mass. I wouldn't pull even a modest vacuum on any vessel that is not engineered for it (again). 

Sorry to hear that you have imploded some of your vacuum stills and about your challenges concerning cuts and efficiency.  The info that you need to do the proper design calcs for your vacuum stills so that they won't implode is online, so there was no reason for that. Out of the 50 or so vacuum stills of various designs that we have built, none have ever imploded.   Two of them are 500 gallon capacity and are currently being ran 2 shifts per day by a nutraceuticals company.

Our beverage ethonal vacuum still 5-150 kits require a 300 series stainless vessel that has wall thicknesses of at least 1.65mm for vessels  smaller than 48" in diameter and for vessels larger the requirement is 2mm.  Our 5-150 beverage ethanol vacuum kits only pull enough vacuum to distill at 150 F at the lowest.  They are not capable of pulling any more vacuum than that.  They don't even use vacuum pumps.    If the stills columns are copper a 2mm wall thickness is fine for up to an 8" column. If your still meets those requirements we will supply you a new still if yours implodes using our kit, but that will never happen.

 

Our kit connects to the parrot connection of the still and the parrot connects to the output on the kit.  Output comes right out of the parrot as it normally does  I recommend doing the cuts by taste and smell for the first few runs while recording the proof then use that info but still taste and smell to be sure.

   We are currently selling 1 to 2 vacuum stills to the hemp to CBD processing facilities per week.  Those stills have 3 mm and greater wall thicknesses and distill at  as low as 80 F.  They are incredibly fast with run times of 1hr for the smaller ones and 1.5hrs for a 500 gallon at 50 C (122 F).   Our falling films will be even faster. 

[seventh son]

16 minutes ago, Southernhighlander said:

Sorry to hear that you have imploded some of your vacuum stills and about your challenges concerning cuts and efficiency.

The tanks I imploded wore more or less expendable. That was years ago during Some trials and experiments. I wasn't trying to scare anyone away from vacuum distillation, my point was that you can't operate any still under vacuum. Obviously, you sell units that are designed for vacuum operation. I like what you're doing.

The challenges of making cuts and the inefficiencies are just a couple of the trade-offs of vacuum distillation. If it wasn't worth the trade-offs I wouldn't still be distilling that way!

[Southernhighlander]

1 minute ago, seventh son said:

The tanks I imploded wore more or less expendable.....

The challenges of making cuts and the inefficiencies are just a couple of the trade-offs of vacuum distillation. If it wasn't worth the trade-offs I wouldn't still be distilling that way!

I hear you.  We have destroyed some vessels in other types of testing. 

 

I agree that the trade offs are worth it depending on what you are doing.  Good job and good luck moving forward.

[Galapadoc]

On 8/4/2019 at 9:26 AM, Southernhighlander said:

We already have vacuum stills for sale if anyone is interested, including the flavor infusers, except ours are a lot prettier than 7 brothers.

Hi Paul. I don't see these on your website. Am I missing something?

[Southernhighlander]

Galapadoc,

 

They aren't on the web site.  For information and or a quote email: paul@distillery-equipment.com.  We have several sizes of vacuum stripping stills in stock.  We also have short path stills and rotary evaporators that operate under vacuum as well as lab chillers that go down to -40 C, heat sources and vacuum pumps.

[SlickFloss]

• This is one of my all time favorite threads of all time.

[CountySeat]

For botanical extractions, what vacuum pressure is recommended? We are starting to run some experiments with a basic set up but I don't think we have enough vacuum from the vacuum pump to distill at low temperatures. I've been poking around for resources and calculators for boiling points of ethanol/water mixtures, but am not finding a clear resources. We are looking to do some basic extractions of botanicals in a roughly 40% ABV mixture with lower temperature distillation. We have a basic water vacuum pump.