Avak

Distillers are at a disadvantage because they can't see inside their still as it is operating... except peaking through a sight glass. A puke doesn't happen suddenly. In my glassware still, foam builds slowly in the pot, then fills the column, then across to the condenser. Its only when it hits the condenser that things happen suddenly. The foam condenses into liquid, which is much more dense than the foam in the column, and the difference in density siphons more foam into the condenser, creating a chain reaction. Some large commercial stills have a vacuum breaker on the still head to prevent this. If the vacuum breaker doesn't work, the pot "flash boils" in the partial vacuum (it can get as high as 5 PSI in a big pot still puke) and the entire boiling contents of the stillpot ends up on the gallery floor. From what I've seen, foam doesn't "climb walls". It just fills volumes. It is denser than vapor, so gravity pulls it down. High vapor velocity in the column can push it "uphill". Its not like foam is evil. But controlling it is part of running a good operation. If I don't need to worry about puking, if I can run my still at its full capacity and if I make a bit more product in a workday, I'm happy. I've not invented anything. Distilling lore is full of anecdotal use of many things to control foaming. I did a controlled comparison of accepted defoaming agents. It's nice to know what works. And it is interesting that some stuff works better than simethicone. I don't have anything against simethicone. Other than I have to source it from a supplier instead of my grocery store. But some customers get wierded out when there are "chemicals" in the hootch.

Doing separate distillations sounds like a rational, systematic approach. But it doesn't work. Flavours are very fickle and short lived unless they are "fixed" with oris or angelica. What tastes magical on Monday may be insipid by Wednesday. Avak

It is very difficult to rig a Carter Head from standard laboratory glassware. The closest I've been able to jury rig is a Soxhlet Extractor topped with a 24/29 reducing adapter. This is more like a gin basket than a Carter head. Avak

You're right. It isn't a quality issue. it is a productivity issue. Leaving 15% more pot capacity as headroom means 15% less product at the end of the day. Its like running a 15% smaller still. However, if a cup of olive oil increases production by 15%, that's a pretty good return. In the tests of different defoaming agents, my little test still had 22% higher output when foam was controlled. The benefit would likely be less on a production still. Foam blocks vapor and heat flow, decreasing effective volume of pot or column. It decreases the effective diameter of a packed column. If there is no sight glass, the operator never knows if there is foam inside. Not so big a deal with a plated column.

I tried soap. It didn't work as well as simethicone so I didn't include it in the formal test. The problem may have been that I am adding defoaming ingredients to cold wash, not a hot still pot. It may be the soap was not dissolving, so not getting to the job site. Recipes are given per liter of input wash. For instance, my favorite is 100ml olive oil + 1tsp DWLD (dish washing liquid detergent) per 10 gallons of wash. I have read foaming blamed on CO2 in the wash, accompanied by recommendations to "de-gas" the wash. My test still pre-heats the wash and runs it through a separator to eliminate CO2 before injecting wash into the column. It still foams like crazy. I think the gas inside foam bubbles is water/ethanol vapor, not CO2. At the beginning of a batch run, there are heads vapors as well. I think head vapors are responsible for the rush of foaming seen with a puke, just before the still comes to operating temperature. The reason a spray of cold water kills foam is because it condenses these vapors, not because it makes CO2 disappear. Received wisdom says protein is the surfactant that cause foaming. I have tried to reduce protein with a protein rest and boil-out during the mash, proteolytic enzyme (Papain) after fermentation, double racking and pre-heating to 97C with filtering before injecting wash into the column. All this made my column and still much cleaner, but didn't help reduce foaming. I wonder if the villain is something other than protein. Avak

I recently tried some defoaming additives because I was having trouble with foaming while stripping barley malt mashes. I had previously used simethicon (silicon oil) with success but I was looking for a DIY defoamer, preferably made from grocery store ingredients. The test still I used was a continuous still made of laboratory glassware. This was a good opportunity for testing defoamers since I could see what was happening inside the pot and column. The still pot was a 2 liter glass flask in an 800 watt heating mantle. The column was a 500mm “thorn” column with the wash injection point 2/3 of the way up the column. The set-up is particularly prone to foaming due to its small volume. The still was warmed up and brought to a steady state with wash, fed by a digitally controlled stepper motor peristaltic pump. Each defoamer was mixed into a liter of wash with a blender-on-a-stick. A liter of wash with the test defoaming agent was run through the still. I observed how well it knocked down existing foam, and the new steady-state foam level. I measured how much of the column was blocked by foam as well as how full of foam the reboiler pot was. After the 1 liter test, the feed was switched back to wash with no defoamer until the still returned to steady state. Then the next test would begin. For silicon oil, I used “Five Star Defoamer 105”, 2 drops per liter. This is 1:100,000 dilution, or half the maximum recommended by the FDA. The other defoamers were various strengths and combinations of olive oil, butter and dishwashing liquid detergent. Results: BEST (No foam in column, surface of boiling Reboiler wash visible) 1 tsp olive oil or ½ tsp olive oil + 1 drop dishwashing liquid detergent (DWLD) OK (foam blocking 2” to 6 “of column) ½ tsp olive oil or 2 drops DWLD Ineffective (Reboiler full of foam, column full of foam) 1 tsp butter or 1:100,000 simethicon The olive oil, alone or with DWLD, was the clear winner. I was surprised at how poorly the simethicon performed since it is so effective at “knocking down” foam in an open mash tun. Adding DWLD to olive oil keeps the oil in suspension if the mixture is stirred up with a “blender-on-a-stick”.

Here is a picture of a dry fired element. Hmmm...... Avak

The specific heat of 20% ethanol is roughly 10% lower than water. Not so bad. I think the pond is a better heat dump than the ground, but thermodynamics was never my strong suit. The waste heat is also used for in-floor heating in the office and lab areas. With the present counterflow cooler, the system works well if the mash pump speed is kept slow. We have tried recirculating the mash through the cooler at higher flow rate, but the total cooling time was the same... about 15 minutes. I never bothered measuring temperatures of anything except the mash, because the system worked perfectly from day 1, even in the summer. Plug and play. Avak

Hi. I have a similar problem. My plan is to re-purpose a small SS conical fermentor to make a press. I plan to cut a circle of perforated SS sheet just a bit smaller than the inside diameter. This is dropped inside, making a self-centering false bottom. Pump the mash into this filter/fermentor slowly and let it drain through on its way to the chiller. Once the mash tun is empty, drop a circle of SS sheet on top of the wet grain. Rig the pump to suck from the bottom of the filter/fermentor and pump. Atmospheric pressure on top of the non-perforated sheet squishes the grain like a grape press. I can see potential problems if your pump generates a crushing vacuum. Check out the pump specs first. It will say the height the pump will prime itself. This can be 5 meters (7.5 psi) for a FIT pump. This is serious pressure. Over the area of a 24 inch disc, that is over 1000 lbs. A "T" in the suction line hooked to a water vacuum break should prevent "squashed beer can" surprises. Another potential problem is a poor seal around the non-perforated disc. A circle of polyfilm 2" larger than the disc laid between disc and grain should provide a seal. If it works as planned, you still need to get the compressed grain out. A floating rope (Spectra, Dyneema) attached to the center of the perforated disc should end up on top of the grain "cookie" when the non-perforated disc is removed. This hasn't made it to the top of my project list, but i will keep you posted. Avak

OPENING POST: Hi folks, I've been distilling as a hobby for quite some years and have decided to try my end at a bigger and more "legal' operation. I want to make a grain based vodka and use it as well to make some gin. From what I've been researching I need to cook my mash, through a jacqueted mash tun so as to prevent scorching. I am looking at this item right now https://shop.distillery-equipment.com/collections/stills/products/200-gallon-mash-tun-stripping-still and my question is, can I strip my mash and then transfer it to another still like this one to finish my vodka ? https://milehidistilling.com/product/53-gallon-copper-6-inch-diameter-mile-hi-flute-6-sections/ Would it work, or am I missing something? Just so you are aware, the mixing motor on the mash tun has a 3 phase motor. Great if 3 phase is available on your site. An added expense if it isn't. Avak

Re: the 20% ethanol geothermal system. Explosion is not an issue since the pumps and controls are in the mechanical room. Only cooling lines enter the (explosion proof) distillery area. A coolant spill is treated the same as a spill of product. The system is only serviced by a commercial geothermal company. The system works so well there is no heat pump, only heat exchange coils in the pond. If cooling requirements increase with production, a heat pump could be added. Avak

We use a geothermal closed loop cooling system which runs through coils in a pond. The system is filled with denatured ethanol solution. I believe it is 20%. The distillery is on the Pacific Coast so there is little need for antifreeze effect. The pond seldom even gets a skiff of ice in winter. Avak

I use cheapo panel mount digital thermometers from AliExpress $1.85 each. They are available with 3 or 10 foot chords. You might find them with longer chords. I always use them in pairs because I just can't trust anything that cheap, even if they have never malfunctioned. Stuff both probes into the same thermometer well and the readings are always within 0.2C . They are much more accurate than the stainless steel analogue thermometers the still came with. I stick all the readouts together on a vertical panel about eye height, using double faced foam sticky tape. They run on 2 button batteries (included). There is no on/off switch... they are always on. I haven't had a battery go dead in the 1 1/2 year I've been using them. They are not advertised as waterproof, but they survive regular splashing. I buy them by the dozen. They get used in the yogurt maker, the refirgerator, the beehives etc. Avak

The column is 4" X 6' packed with ceramic rings over a 3.5Kw bain Marie. It is now operating as a batch still since our distillery does not have fermentation capacity to run this size continuous still. And with just an 8 hour shift, we are not keen to try. Other posts have been very perceptive about balancing fermentation, manpower, cooling, etc. A continuous still is a demanding mistress. There is no substitute for experienced advice before signing the check for a new still. My interest in continuous distillation is to design a recovery still to recover low concentrations of ethanol from backset and tails. Better the hootch ends up in my inventory than down the drain ! One small scale still with a Vigreux column recovered 89%ABV from 1%ABV backset. But it was a slow process. It would need to run unattended overnight and we know what this forum thinks of unattended stills ! Is a recovery still a dumb idea? I've never heard of anyone doing it so I wonder if I'm out to lunch on this. The purpose of my previous post on conversion of a batch still to a continuous still was to suggest a low cost way to re-purpose existing equipment. If the result did not fit in the operation, little would be lost and fun would be had. Avak

At the risk of inviting a flaming, here is a suggestion from a newbie: modify your existing still to run continuously. 1) You will need a well-functioning column (either plates or packing). Tap into the column 1/3 of the way up for the beer input. Having a flow gauge on the dephegmator coolant is desirable. 2) You need a level control on the "pot" (now the reboiler). A simple overflow with "P-trap" and vent will do. If there is appropriate existing access, great. The reboiler level can be as low as about 15% of the pot capacity. It could be anything higher, so chose a level compatable with your heater. If you must make a siphon, remember you can't siphon a boiling liquid. The siphon tube needs a cooling jacket to prevent vapor lock. If you use incoming beer as the cooling liquid for the siphon, it serves as a pre-heater for the input. Otherwise, use reboiler discharge and a heat exchanger as a beer pre-heater. 3) Install lots of digital thermometers.You want to know reboiler temperature to 0.1C (since this will tell you how much ethanol you are losing in the discharge), input beer temperature, column temperature at the input level, below the dephlegmator, and at the head. 4) Turn down the kilowatts. The reboiler has a much smaller liquid volume than the pot did. It will flash up to operating temperature fast. Once stabilized in a run, it will require about the same power as when the the still was operating as a pot still. 5) The beer input feed needs a positive displacement pump (like a peristaltic pump) with a speed control and flow meter. 6) To operate, run the beer feed pump to bring the reboiler to operating level. Turn off the feed pump. Turn on the dephlegmator cooling flow. Turn on the reboiler power. Allow reflux to fill the plates. Turn down the 'phluger flow and juggle beer inflow rate + power level to maintain desired output ABV (I strip to 85% with my packed column). If reboiler temperature drops, turn down beer flow or turn up power. If output ABV drops, turn down beer flow. A continuous still like this will not separate out the heads. This will need to be done on the spirit run. Production rate will be about the same as when operating as a pot still. However, it heats up faster and this only needs to be done once. The longer you run it, the more the time savings adds up. If you need to take a beak, it will restart rapidly. If the beer is pre-heated by the siphon cooling jacket, it will boil and make percolator noises as it burps its way up to the input. No worries. Like any still, you can't turn your back on it while it is running. After lulling you to sleep with hours at the same settings, it will surprise you. Avak