Silk City Distillers

Sometimes it helps to alternate acid and caustic cleaners.  Especially in the tun or still kettle, where it's easy to start getting build up deposits.

Do you have a port for a spray ball and a pump to run it at high enough pressures?

Sure, that's an option, there many commercial gin stills setup in that fashion.

The reason for the Carter Head as a device are exactly as you state - ease of operation for vapor-extracted botanicals.  Secondary to this, some feel that draining the Carter Head "tea" back to the alcohol in the boiler can cause off-flavors, bitterness, earthiness, astringency (based on the botanical type).  Instead, the carter head allows for the draining of that condensate separately.

Keep in mind, there is sometimes the need to change baskets multiple times during a run.  The carter head facilitates the change out.  In your model, it would be very difficult to juggle the hot  column, condenser, parrot, etc to swap the basket.  Make the basket big enough so that you don't need to change out, problem solved (just don't blow your self up).

Suspension of a bag works, but is less efficient than an in-line basket - as vapor is forced through the basket, ensuring high contact, versus in suspension, where it's much more passive contact.

High solids = sugar or sweetners?

If so, invest in Alcodens LQ and take the time to do the work up-front,  to ensure your final proof is on target.

Trial and error proofing (why so many people do this, I don't know) would be an absolute disaster if you are proofing via distillation.

Your final proofing should only be a confirmation of the proof you expected out of whatever processing operations you were doing.

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.

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.

I feel like there is enough drift on the handheld Anton Paar units that you need to recalibrate with distilled water every day.

Wondering if anyone else has had the same experience.  We use the DMA35 for quick, intermediate measurements, and we use Alcodens for all proofing/dilution calculations.  More than once I've gone through proofing (which may extend more  than a day) with Alcodens only to realize the DMA35 was off by a few tenths.  Alcodens calcs are always laser precise, the density meter, not so much.  Nearly every time when the measured proof had a deviation from the calc, it's just that the meter was off.

Glass rules.

If you are working with sugar additions (honey),  start honing your lab skills, a digital density meter is not going to save you any material amount of time.

We find that from a flavor perspective, batch to batch consistency is improved by recycling heads and early tails.  Single pass whiskey on plates.

We don’t commingle distillate from numerous batch runs before barreling, but lay down barrels on a run-by-run basis.  We did a number of barrels without prior run feints, and they tend to have a wider flavor variance and are generally less complex than the barrels that immediately follow, which do have feints.  We are incredibly obsessive about following process, so there is typically very little other variation introduced.

For a stretch, we did not recycle, the flavor profile of that finished product is significantly less complex. It’s good, makes a wonderful barrel strength, but proofed down, it’s pretty “basic”.

But, Devil in the details, and there are lots of details for those devils to hide in.

Sounds fun.

Lavender oil is traditionally produced via steam distillation - where your outputs are lavender oil and lavender hydrosol.  You will need the ability to pass steam through a large volume of lavender plants.  The  condense the vapor, and depart the oils fro  the water (hydrosol).

Lavender extracts can be produced by solvent extraction, but the process is very different.

Rinnai has done a nice job partnering up to meet brewers needs.  I'm not talking about big setups either, but the little guys.  So you know it's cost effective.

https://www.rinnai.us/sites/default/files/marketing_materials/R-CSWH-E-29.pdf

On the straight malt side, meaning no cookers, I've seen a few guys do pretty well using the Rinnai on demand commercial gas heaters in parallel.  I think they are 299k BTU per unit.  Just add up as many as you need.

Just need to run the sizing calcs to understand the maximum flow rates at the temperature you need.

From an operating cost perspective, hard to beat.  Footprint, tiny.  Most plumbers know what to do with them, and most inspectors are pretty comfortable with them.

Being able to adjust your reflux condenser temps on the fly makes exploring whiskey heads technique fairly interesting, especially if you have a few plates to play with.

For example, running high reflux to stack heads, slow take off >190pf, then flipping off the reflux condenser entirely and shifting to quasi-pot mode.  You can get the product yield efficiency of a column, and the flavor profile of a pot.

Yeah, moving to roof-mounted dry coolers is going to be a big shift for us.  We would need to do closed-loop glycol and HX to the existing water system, or bite the bullet and shift.

Our chillers are inside - great during the winter.  Awful during the summer, especially with 100f degrees expected this weekend.

Don't mind me, I like to argue.

If I'm running my chillers at 50f set points - what's the difference between water and glycol?

Both cause corrosion without inhibitors - arguable that uninhibited glycol is far worse due to decomposition.  Yet, I know plenty of brewers running uninhibited glycol.  Every day we talk about people using their condensers to heat straight water, or just use city water for cooling.

What's the benefit of running sub-freezing temperatures and using glycol?  My jackets and condensers all operate just fine with 50f coolant.

Good luck controlling a dephlegmator with sub-freezing coolant - all it takes it a tiny PID/Control upset, and the column goes full reflux with  sub-cooled reflux - a serious PITA.  Having to feed the dephleg coolant through the product condenser to temper it seems like a major compromise, because it links control of both condensers.  Trying to run high reflux and slow product rate will almost always result in overcooled product (wasted energy).

Sure, warmer coolant likely needs higher flow rates, get it.  But water is a better coolant than glycol mix, so it's got slightly better heat transfer, which likely reduces the necessary flow rate.

I have city water plumbed into my cooling system, so if my chillers fail, or I run out of capacity, I can just backup with regular water, with no worry about losing glycol down the drain.

I mean, if I was running lagering tanks, I get it.  If I was using the chillers to cool a cold box, I get it.  If I had an undersized coolant reservoir, thus need to run a lower temperature to increase my cooling capacity, I get it.  If my fermenter jackets were minimal, I get it.

My Rotovap chiller runs at -25c fixed, so that's running glycol/water, so I get it.

What am I missing?

Poly Tank - chillers directly cooling the water.  We only cool to 50f, so no need for glycol.  We get some condensation on hot humid days, but 50f is a good balance for us.  

We run roughly in the same ballpark.

Our tank is a little more than 2x the still volume, we run 4.5 tons.

As long as we pre-chill the tank to 50f, we can make it through a run.  If the tank starts warm, say 75f, we can not make it through a run, even with the chillers on.  The tank and chiller can not keep up with a fast strip - but this might be due to our product condenser size (need to be significantly larger with a slower flow rate).  The chillers easily re-cool the tank by early morning.  

On the mash cooling, I think you are optimistic, the delta-t is significantly smaller.  As soon as the tank starts to warm, the cooling time will start dragging out substantially (unless you have a massive heat exchanger).  I would imagine you'd need 3x the mash tun volume, just to keep the coolant temperature low.

Our fermenter chillers are separate from our still chillers, for exactly the reason MG mentions.

We would have went larger, but we don't have 3 phase.  We'll eventually put dry coolers on the roof, since we live far enough North to be able to cool air temperatures for half the year.

We do anywhere from 1000 to 3000 pounds of hammer milled corn/rye and roller milled wheat/barley a week using a half a large (36") rotomold tank with a #6 stainless mesh screen and a squeegee.

Our liquid is not completely devoid of solids, but the resulting liquid is reasonably cleared, and the resulting solids are reasonably dry.

500 gallons of wash that contained 1000 pounds of grain will fill 8 20-30 gallon lock ring barrels (or about 3 55g lock top drums) - just to give you an idea of the overall solids capture and overall volume reduction post distillation/separation.

Screening in this fashion, it is critical that the stillage be very hot.  Once the stillage falls below 100F, the viscosity makes it nearly impossible to screen with this method.  You may need to add cold water to the outflow to reduce the temperature to meet your discharge reqs.

The squeegee and it's operator are a critical part of this operation.  The screen will blind very quickly otherwise.

It takes about 20 minutes to separate a 1000l batch (~265g/~500lb).

Roller milling the barley helps keep enough husk in the mash to aid separation post distillation, but this is not entirely necessary.  Our rye is 100% hammer milled rye and will separate pretty well without massive solids bleed through.  The husk from whole oats is awesome in this regard as well.

We've been considering ponying up the $15-20k for an asian-sourced separator unit, screw press or centrifugal screener - but considering the effectiveness of this very, very, low tech approach, it's a tough decision.  I don't think a machine will end up saving any time over this process, since the clean up will likely take the same time.  However, it would make things much easier, as the separation process is hot, steamy, wet, messy.  We do it over our floor drain area, which makes clean up relatively painless.  Trying to do it without the ability to wash down floors, good luck.

Brewers pasteurize for microbiological stability, as well as to ensure enzymes are denatured and do not remain active in fermentation and bottling.  Distillers generally don't care about either of these two, as our "beer" is an intermediate product, and is not directly consumed.  Therefore like @vsaks says, many of the techniques used by brewers to ensure a beer has good body, head retention, residual dextrin, isn't a cesspool, etc - these are all generally negative or irrelevant to a distiller.  Ok, maybe not the cesspool part, which is why you see distillers purposefully acidify their mashes with direct acid additions, something you rarely see in beer (although I hear some cheater sour techniques are becoming popular, using lactic, malic, etc).  While a brewer might hate lactic acid bacteria, the fact is, a typical malt barley wash is teeming with LAB, and there is plenty to indicate that it's beneficial.

You can find plenty of similarities, and differences.  For example, look at the ideal single infusion mash temp for beer.  It's around 152, right in the ballpark you mentioned.  But for whiskey, you might instead sit 145-148 for 90 minutes, emphasizing beta and ensuring a more complete conversion (if not using glucoamylase).

And like I said above, if you are using glucoamylase, you never want to pasteurize and denature, you want that glucoamylase active throughout fermentation.  If you did that in a beer, you'd have a pretty dry, thin, brut-style beer.  Probably awful.

Being a great whiskey distiller absolutely requires a thorough understanding of brewing technique, however, it doesn't mean that you'll execute your process in a way that's ideal for brewing over distilling.  That understanding and expertise is absolutely necessary to understand that difference.

Keep in mind that you can really only use a refractometer for your starting gravity, and ideally you would have calibrated it against a known hydrometer for your type of wash (grain, fruit, sugar, etc).

The irony of arguing about a heads cut in a topic started by a brandy distiller.

Heads?  That's not heads, that's flavor.

Oversimplifying, the closed cup temperature represents the minimum amount of vapor to sustain a "flash" burn in a closed container.  It will not burn, but will flash.  The fire point is the temperature at which the distillate will sustain combustion for at least a few seconds.

The initial question, 'what temperature will begin to lose alcohol to vapor' - that's the closed cup point.  It might be a tiny amount of vapor, and not enough to be an issue from a hazard perspective (lots of factors in play there), but it's still losing alcohol as vapor.

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I want to know what is the hottest water temperature we can use in our condenser before we start to lose alcohol vapor that will not condensate?

 

Since you asked.  The hottest temperature you can use is the hottest temperature that will keep the distillate temperature under the closed cup flash point listed in this chart.

Suspect many will be surprised by this, since you get to some fairly cold temperatures as you approach azeo.  Are we talking about large losses if you go over these numbers?  No, but that's not what you asked.

80f input water to a condenser means that in most cases, vapor is going to be generated.

Consider buying a Porsche or Ferrari instead, the resale is better.

Ok I was just joking around, but that’s just crazy.

I use alcohol sometimes when cooking chicken, but not the other way around.

I need to try this.

Too bad it wasn’t heavy rum, people pay extra for dead rodent.

Have you inspected the grain closely?  Maybe some mold?  What's the flavor of the low wines?  If it's earthy, potato, mushroomy - that's indication of mold.

Friend of ours showed us an easy way to test grain.  Put it between two wet paper towels and microwave it until it's hot.  Take a good smell.  We got some grain from a local guy once that we suspect got rained on, we didn't use it for a few days, ran the test and it was very musty.  Ended up having him take it all back.