Silk City Distillers

Why not change the color? If someone is so wedded to the color, they'll be wedded to a brand. Why not go off an a tangent and use something different? It even works to tie into your marketing, no bugs, no fake stuff. Are you drinking beetle juice? I followed the Starbucks backlash on carmine closely, there aren't many good alternatives. I think someone is trying to use some fancy genetic engineering to create an organism to create the carmine red in a tank. But who knows if it will be listed as natural, and is GMO any better for you? Approved colorings are limited.

Bet that came from the health department, file that one right alongside the requirement for a grease trap on a 3 basin sink.

I wish I had a picture of the still together, but the 12" Stilldragon glass column will remain in hiding up in the office until we finish the rest of the concrete work and construction. Should get final plumbing in the next week or so and can move gear into place. The weight and size of the larger equipment required heavier bolt flanges. While the glass sections are fragile, the rest of the column and still are so overbuilt it's silly. Once together the column will be relatively sturdy and stable.

In the big picture, aren't the ideal or minimal coolant flow rates and temperatures as important as the physical size and design? When everyone is talking sizing here, I understand it's easy to just describe things in terms of height and width, but what's the design coolant flow rate and temp and what's the minimal? Designing a heat exchanger for expensive 75f municipal water is going to be a very different exercise than designing a condenser for a 1500 gallon 50F chilled water reservoir.

We have experience dealing with Stilldragon. All-in-all it's been great and we would do it all over again. Their work is top notch. Larry and Lloyd are stand-up guys, and stand behind their product.

We commissioned the SD team to build us a 12" diameter glass column, 4 plates (pro cap style), 1000 liter steam jacket boiler. End result was better than we'd expected. Yes, it's absolutely eye candy. But then again, so is the engine turning on a german still, I don't know why that would be a criticism.

Stilldragon has a large and active user community, you might want to spend some time there. In addition, if you have some special requirements, just ask Larry, they can build you pretty much anything.

Here is a reference that says prolonged exposure to 5,000ppm is sufficient to create the symptoms associated with intoxication:

https://books.google.com/books?id=e4_S46UcI2AC&pg=PT88&lpg=PT88&dq=ethanol+vapor+concentration+intoxication+ppm&source=bl&ots=owD-vGBc2G&sig=fimnaS0VCPbqF_vU7sQtiC6dYjs&hl=en&sa=X&ei=heqvVJOIKYeegwS77YPIBg&ved=0CFYQ6AEwCTgK#v=onepage&q=ethanol%20vapor%20concentration%20intoxication%20ppm&f=false

Which I suspect means if you at all feel intoxicated by exposure to vapor, you are well over the legal limit per OSHA.

OSHA defines a permissible exposure limit for ethanol vapor, and you can easily find measuring equipment to let you know what it is.

I believe the legal permissible limit is 1000ppm over an 8 hour shift. I think this corresponds to something like 3% of the LEL, but don't quote me.

https://www.osha.gov/dts/chemicalsampling/data/CH_239700.html

http://www.cdc.gov/niosh/idlh/64175.html

How do you deal with cleaning of the condenser if you run vapor through the shell? Do you have some sort of setup that allows for flooding of the exchanger?

Maybe it's irrelevant for a stripping setup, but seems odd to do this in any other situation. I could imagine all sorts of potential negatives. If the shell is baffled, there would be numerous areas to catch distillate resulting in smearing of fractions. I've never seen a tube in shell with a shell side that was condusive to draining. There isn't any position that wouldn't result in some pooling. Running mixed products would be significantly more complex, especially if you are going deep into the tails or running a gin or other infused product. The shell is going to get fouled.

What do you estimate the potential efficiency benefits are of running reverse? 5%? 10%? 50%? What size reduction does that translate to? There isn't any difference in heat exchange at the tube, since the distance between the coolant and the vapor is still the same in either case (the width of the tube wall). Yes you gain some benefits of the outer wall for exchange, but unforced room temperature air is generally a poor cooling medium.

Heat exchanger is a heat exchanger is a heat exchanger.

Thanks for the feedback Joe, good to know.

Went eBay as well, we were able to get a two 2" sanitary positive displacement lobe pumps for a fantastic price. Most high quality sanitary pumps are primarily stainless and are designed to be cleaned, even aggressively so, so I wouldn't worry. In addition, these things are wildly expensive new, so more than likely, they were used in food or pharmaceutical production, as few other uses could justify the price tag new. One of pumps was used to make Aquafresh and Sensodyne toothpaste, the other one was an unused spare. We needed to fabricate a cart and wire up a VFD for speed control, but that's minor, overall we saved a small fortune. All in these two pumps would have probably cost us more than $15k new, I think we're in to them for about $1500.

ASD - I've got to assume that most are running that scale equipment are doing so in a quasi-batch manner, otherwise we're talking about production capacity in the hundreds of thousands of cases annually. Is it safe to assume that a typical user might not even run every day, let alone 8+ hours a day, every day? Or, perhaps, congratulations are in order.

Given that every design must still obey the laws of physics, what's the benefit over large scale batch distillation with the same output? To accomplish a continuous run in the same timeframe as a batch run, the energy and cooling requirements are nearly identical (save for some benefits of using the beer feed for partial cooling). Using a continuous still to strip 500 gallons in an hour is going to require roughly the same energy input as a single 500 gallon strip distillation run in 1 hour. Likewise, it will take the same cooling capacity to condense the distillate output on both systems.

I can understand if you are utilizing a continuous distillation approach to spread the distillation over a larger number of hours, perhaps if there were some restrictions on steam boiler sizing, electrical service, or even floor space. But to run a continuous still as a batch still? Seems like you are adding complexity with little overall benefit.

What am I missing?

If you are brave, you can pick up a 600kbtu stainless steel pool heat exchanger for about $500 bucks on eBay, or the smaller 300kbtu for $300 or so (although the 300k looks pretty small). I would imagine it would be difficult to make it yourself for less money. No experience with how well they work, but I've always wondered. They are either a complete waste or money or they best bargain around. You can probably dig up the specs if you dig hard enough. Other nice thing about most of these is that the tube side runs straight through, so you don't need to push the vapor through the shell. Some of these even have the convoluted tubes.

Seems like a high price to pay for what is essentially a big unheated stainless pot, and only 193 gallons, 1.5" TC output Seems the potential negatives outweigh the potential positives (pretty stainless tooling). And to consider that you might need to modify the tank too? I would say the agitator might be OK for even stiffer mashes, you have a full horsepower geared down to under 100 rpm, and that shaft size looks sizable as well (hollow?). But there seem to be plenty of other options.

I'd first start looking in the surplus market, process tanks from the food industry, under 200 gallons, are readily available and easy to ship. You might also find one with an larger sized agitator as well, and potentially even some other benefits like a steam or water jacket, or insulation.

Open top dairy tanks are also easily modified, and many can be found insulated. If you don't think you'll ever install a steam boiler, and if you live anywhere near dairy country, it's the cheapest way to get a nice sanitary stainless insulated tank

Another option would be a new Stainless IBC tote. While they aren't as pretty, they'll last forever, with a wall thickness of more than double that Letina tank (you can ding the Letina, you'd never ding a tote). A brand new Custom Metalcraft 350 gallon open top tote is only $2000, with jackets about $750 a side. Would require a little bit of fab, but adding a bridge and agitator shouldn't cost you more than $1500. I bet you custom metal craft would probably build the bridge for you too, heck they might be interested in talking, since they appear to be making significant inroads into distillery and brewery hardware. Adding the jacket now would give you a mechanism to cool down in the tank, and if you ever went steam later, you'd have the ability to run the jacket to heat.

Don't get me wrong, the Letina tanks are nice, but you aren't getting a whole lot of bang for your buck.

Geez, a politician? C'mon.

There isn't an easy answer to the question, and the minute somebody posts something that looks like one, two more people are going to jump in with why it's not the answer.

The speed of your still is governed by 3 things, column diameter, reflux ratio, and input power. Think of the column diameter are your speed governor. You can't push faster than the governor without causing all sorts of problems, entrainment flooding, or 'smearing' like Dehner mentions. Input power should be obvious, the more heat input to the boiler, the more vapor you can generate. Reflux ratio, however, is the speed bump. When you don't have enough column height to hit your target ABV, you need to increase the reflux ratio to compensate, and the penalty for this is lower takeoff speed. In your example, you are getting hit by 2 issues, not enough column diameter, and needing to push a higher reflux ratio to hit your vodka. 28 hours is off the charts though. What you don't have a problem with is power, you have more than enough.

On a packed column for a 60 gallon still, I'd go at least 4", for bubble cap trays I'd go either 6 or 8". 6" if I had 10+ trays for vodka/neutral, and 8" for a whiskey/rum column to be able to push for faster run times. That's just what I would do.

Theoretically, given identical design parameters, if you were able to scale your trays from 4" to 8", you would be able to run 4 times faster. 8 trays for a neutral is a bit on the low side, so if you are able to either add additional trays, or potentially a packed section, you should be able to hit your target ABV with less reflux, and potentially drive that time down further.

Adding a packed section to your vodka column will probably let you drive it a little faster, with a little less reflux, if adding additional trays isn't possible.

On the stripping still timing, I've never yet seen a setup that the product condenser wasn't the limiting factor on a strip run.

The downside of a pit is that if you need more than a foot or so, you are probably going to be under your drain/waste plumbing, or without enough slope, so adding a drain to the bottom of the pit is probably going to be a challenge at 2 or 3 feet. Building code might also require a railing and or a step if it's considered part of a working area. This is hardly ideal, and is making the best of a bad situation. I wouldn't think anyone would want to go out of the way and put their still in a hole on purpose.

Adding any kind of ejector pump to this setup is probably going to be a major hassle, since a sump under a still is for certain going to be classified as Group I Division 1 per NFPA 497 (see Roger's comment above). You might want to think twice about breaking out the shop vac to clean up a little spill in the sump. I mean, the shop vac will probably do a great job, but then you've got that whole 3rd degree burn and fire thing to worry about.

My assumption was you would just sit the whole still in the sump, and not just the column, because pumping reflux is a whole 'nother issue, and doing it in a Group 1 Div 1 makes it even more complex.

Lots of unknowns here, what's your target ABV output, what's your product? What kind of time constraints do you have? By "hybrid" do you mean utilizing a packed column and trays? What's the packing material? If trays, how many trays? Bubble Cap or Sieve? Why are you even considering a hybrid approach (I would argue this is unnecessarily complex, since you need to engineer both the packed and tray columns to operate within the same set of design parameters for optimal efficiency).

You are going to get a half a dozen opinions, at least. The hobby community has done a lot of trial-and-error design work on packed columns, and there are a number of rules of thumb with regard to column diameter and power input, column height to diameter ratios, hetp, etc that would probably help you. In the commercial world, much of this is either trade secret or so complex you'd wear out your slide rule.

And … the diameter of the boiler is not relevant to column sizing.

Dig a hole.

I recall the folks over at Koval saying they had one of their big stills in a pit due to height issues. All you need is one foot? Cut the concrete and go down.

Split columns is nice, because they avail some other flexibility a single tall column doesn't, but generally the cost will be higher as the vapor plumbing is more complex, requires more valves to operate, requires dual dephlegmators, etc.

Or, put in a skylight?

Unless your boiler was foaming excessively, and carrying a significant amount mineral laden water out the lyne arm and into the mash, I'd look elsewhere. The steam itself should be generally devoid of metals and minerals, and foaming is rare without other impurities being introduced. Did your low water cutoff trigger? Did you use an excessive amount of water?

I'd look somewhere else regarding the unexpected drop in yield. Potential infection is always my first thought, but if you weren't able to maintain a steady power input into your pot, and were boiling in fits and starts, I can imagine all sorts of potential smearing between heads/tails/hearts. Seems like a long shot though.

As you are producing steam from your boiler (it's a boiler, call a spade a spade), you are leaving behind all the minerals and metals, etc etc that are not volatile. These will eventually build up to the point that you see, and will continue to concentrate until you start getting scale build up on your boiler walls and elements. If you have elements, you might notice them getting build up as well.

This is why process boilers have blow down systems on them, to replace the mineral/metal laden water with water of a lower concentration. You should dump and refill. If you don't want to, you can use distilled water as well. If you have a reverse osmosis system, you can use that water as well. The higher the water purity, the longer it will take for the mineral level to build up.

Careful with your homegrown boiler.

You'll still want to confirm allowable discharge temperature and pH with your local sewerage authority.

Let me know if you are interested in doing something with a less distinctive bottle type, we're only about 15 miles apart. That's an awfully nice jug style bottle though.

What always made sense to me from a workflow perspective was matching your mash tun and fermenters in a 1:1, and sizing your mash tun as a multiple of your still batch size. Our mash tun is sized for a double sized batch.

1000l batch sizes are nice because you can use IBC totes as holding tanks. Should you mash and ferment a double batch, it would be relatively easy to move half the batch to the still, and the remainder into the tote, so you wouldn't be keeping your fermenter in use a day longer than necessary.

I've heard similar challenges from the brewers around here, so the analogy approach could be double edged. In fact, we had to go out of our way to explain the differences between brewing and distilling, because the board had the perception that breweries of any scale produced nuisance odor in the neighborhood. We had to propose installing a carbon-based adsorptive dry scrubber on our fermenters as part of our odor control strategy. Anyone else using carbon dry scrubbers on their fermenters? I'd love to know if we're the first. Even the engineers at the big carbon houses were scratching their heads.

Hinging your plan on the local government to change the zoning and law carries with it risk. Not only timeline risk, since those guys move at the pace of cold molasses, but also risk that the change be denied. Zoning and master plan changes are generally not fast actions, at least around here they are not. In addition, there is huge risk of the unknown, since once they open the door to allow it, approvals are no longer on a case by case basis. While we might think it's great, the local community might see this as opening the door to dozens of problem businesses.

The biggest issue we faced from the local governments and zoning was a fear of the unknown.

Not following, are you trying to get the city to change the zoning to accommodate you, or are you going before the planing board for a variance to allow you to operate in a zone other than permitted?

Similar story in our area, distilleries classified as permitted in the heaviest of heavy industrial districts. However, none of these areas are suited to our type of business.

We found an ideally suited property in a Business/Commercial zone, and because of the zoning we needed to petition the board for a variance to allow us to operate. It required an Attorney, an Architect, and a Planner, as well as expert testimony from a distillery owner in another township. As expected, the major hurdles were potential negative impacts to the area, and we had to provide additional testimony on the positive critera of allowing us to operate.

Recipe approvals aside, it sounds like an interesting experiment.

My first question isn't around whether or not you can ferment it, you'll be able to ferment it, the question is whether or not it will be worth your time once you've factored in the total cost. You'll need to understand the yield very well, and I'm not sold on whether or not it's economical, even if it's free.

Second issue is fat content, you are talking about a serious amount of fat. Generally this isn't an issue in the distillery, this may be an expensive issue when dealing with wastewater. Realistically, will you need grease traps to deal with the waste?

Third, what kind of volumes are you talking about there, 100 pounds a week? 1,000? Again, this is going to factor into whether or not we're talking about viable business or fun experiment.

I'd say at a minimum from a process perspective, heat, agitate, adjust pH, use both an Alpha Amylase and a Glucoamylase enzyme to try to break down additional fermentables from the carbohydrates. At that point you'll be able to run a few trials to determine the yield. I strongly suspect you will not be able to easily measure the gravity post "mashing", due to everything else in the mix.

Read up on the history of Kvas, Kvass, or Kwas Chlebowy for some insight into a potential process. This was common in Eastern Europe.