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meerkat

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meerkat last won the day on December 2 2022

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  1. Regarding Golden Beaver's step 5 - weight for weight syrup or honey will reduce the proof by less than water would. The difference in proofing effect between the syrup/honey and water varies with the Brix. As long as you know the Brix of the syrup AlcoDens LQ will calculate for you the exact weight or volume of syrup (or even granular sugar and water) required to achieve a particular target proof. Regardless of how you do the calculation, step 9 of proofing down slowly is probably a good idea.
  2. The unexpectedly low ABV after dilution with the condensate is difficult to explain. The low dissolved solids – which Google estimates as about 2.5% - would cause a decrease of 0.5 – 1% in the ABV, depending on the mass of walnuts in the spirit. A more likely culprit would be moisture extracted from the walnuts if they were freshly harvested and not dried yet. But I don’t think that even this would fully explain the drop in ABV. Do you have any of the original grain spirit left to confirm that it really was 190 proof to start with? If you were to add 375 ml of 66.7 Bx maple syrup to 1 liter of 40% ABV it would decrease the true ABV to about 29% but if you tried to measure it with a hydrometer the apparent ABV would be less than zero because of the extreme obscuration. Measuring ABV and Bx at the same time requires special attention. The official TTB method requires you to distill off all the alcohol and most of the water and then measure the ABV of the distillate. The TTB has produced a good set of videos on this. Part 3 is what you need to watch. A quicker method is to measure the density and the refractive index of the spirit. This allows you to compensate for the obscuration of both the density and the refractive index. I have written up a description of how this works here. It is something like specifying your location by giving the longitude and the latitude and knowing that the lines cross at only one place. You can purchase instruments that perform both the measurements (density and RI) and interpret the results automatically for around $40-50k I think. However, you can get good results with the Anton Paar entry level set of EasyDens plus SmartRef together with my AlcoDens LQ software all for less than $1k. The EasyDens and SmartRef keep their costs low by excluding some of the computational power and the display, and then relying on your smart phone to provide it. This combination would certainly be good enough for your diagnostic work and for product development.
  3. It is probably obvious to those who are working with continuous columns, but just a heads-up to those who are thinking of going that way - the usual way of taking the vapor from the stripping column across to the rectifier is to install the take-off slightly below the top of the stripper. With a continuous stripper there can be some really bad smelling stuff accumulated at the top of the stripper and you don't want to take that over into the rectifier. You need a small sacrificial bleed stream from the condensed heads on the stripper, or by adjusting the condenser temperature to allow the smellies to be vented to atmosphere. It is also general practice to have a reboiler on the rectifier but it would be interesting to see how it would work if the bottoms of the rectifier are taken back to the stripper for reboiling - much like what is done in a craft batch plant. If the rectifier bottoms are taken back to the stripper make sure there is a U-seal in the line to prevent vapor flowing up this line into the base of the rectifier when there should only be liquid flowing from the rectifier back to the stripper.
  4. We always used steel or stainless piping for the dip pipes so I don't know about plastic tubing. The aim was to prevent the alcohol from falling through the air so I would imagine that plastic would be fine if the rest of the piping is plastic. It's a long time ago but I seem to recall there being a limit on the flow velocity to avoid static build up. From what I remember the velocity limits were rather high (> 4 m/s ??) and we never approached them in normal operation. Your fire marshall may be able to advise on this as gasoline would have similar restrictions. This must be a common occurrence in distilleries and hopefully one of the other members can give you current advice for your area.
  5. The LyondellBasell company used to put out a very comprehensive guide to using and storing alcohol but I don't see it on their web page anymore. Copies of useful documents like this do float around the web and if you search for "Equistar Ethyl Alcohol Handbook" you will probably find a copy somewhere. A long time ago when I worked for an NGS supplier we delivered to many backyard vinegar manufacturers with essentially no safety measures in place. Dealing with NGS is not like working with dynamite, but you do need to be careful. Eventually the regulations were changed here and suppliers became responsible to ensure that they did not deliver to unsafe premises and then we would send out technical people to advise the customers. Your supplier may be able to do the same for you. Regarding your specific questions 1. Our staff wore standard overalls and safety shoes. Of course there must be no smoking and no matches or unprotected electrical gear or phones allowed. 2. I have never seen a flame arrester on a pump. The pump discharge should be below the liquid surface in the receiving tank to prevent alcohol from falling through air as this can generate static charges. The vents to atmosphere mostly had flame arresters as far as I remember. 3. Even if you do dilute the NGS the vapors above the liquid can be flammable. I once saw a wine tank explode when the lid was welded while there was wine in the bottom of the tank. 4. I guess flammable liquid cabinets are a good idea in a laboratory, but I have seen plenty of NGS samples standing around on lab benches. It seems to me that you are tackling this matter thoroughly and if you follow the fire marshall's instructions you won't go far wrong.
  6. The small volume and the high ABV make this measurement more difficult. If the maceration is for flavors only (like gin) then you can measure the ABV using an electronic density meter. But with a campari you are probably looking at around 2.5 brix of sugar and you need to take obscuration into account. The small volume rules out precision hydrometers and lab distillation. The NIR and density plus RI methods won't cope with anything above 65 ABV unless you dilute the sample - and therefore decrease the accuracy. If you have an EDM that can give you an accurate density with a small sample you could combine this with the solids content measured by gentle drying to calculate the ABV using software like AlcoDens LQ or similar. At a given temperature the ABV, brix and density are inter-dependent so if you know any two you can calculate the third.
  7. The freezing temperatures given in AlcoDens are for well mixed solutions - as would be the case if the alcohol and water mixture was being pumped around a circuit and used as a very low temperature heat transfer fluid. If the solution is not mixed it can separate on freezing and you would find sections that consist mainly of water that have frozen solid and the liquid portions would contain elevated levels of alcohol. Searching on YouTube for "freeze distillation" should show you some examples. I suppose this is analogous to normal boiling distillation where the vapor that is generated has a higher proportion of the component with the lower boiling point. In freezing, the solid that is generated has a higher proportion of the component with the higher freezing point.
  8. Hi Velten, Welcome from your southern neighbour. I'm in Durban, SA. I wish you all the best with your new venture. Regards meerkat
  9. I hope that @robowop will give some feedback here on his results, but I did receive a DM from him saying that the column is no longer flooding although the leaking agitator seal still needs repair. I understand that he made changes external to the column only. @whiskeytango noted that a possible cause of the flooding could be the downcomer from the bottom tray and certainly in my experience the downcomers are far and away the largest cause of internal problems in a column. But it seems that robowop was lucky here and did not need to make internal changes.
  10. The most important point to understand regarding the control of tray temperatures is that it is not the tray temperature that you really want to control. The tray temperature is just a consequence of the composition on the tray, and it is the composition that you are really trying to control. A liquid with a higher ABV boils at a lower temperature than a liquid with a lower ABV, so the temperature is just an indication of the composition (i.e. ABV). People will say "Of course I can control the temperature - if I put more steam into the boiler the tray temperatures all increase". That is true, but it helps if you understand why the tray temperatures increase. The boiler is the part of the column where you will find the lowest ABV. If you put more steam into the boiler you force this low ABV material up the column and dilute the ABV on all of the trays. And spirit with a lower ABV boils at a higher temperature and so the higher temperatures observed only mean that the ABV on each of the trays has decreased. The opposite effect is when you increase the reflux. Now you are taking the highest ABV material in the column (i.e. the top product) and pouring it down the column increasing the ABV on each plate. Increased ABV means it boils at a lower temperature and we see the tray temperatures decrease when we increase reflux. It's tempting to think that the tray temperatures have decreased because we have added cold reflux, but that is not the true cause. It is the higher ABV resulting in lower boiling points on each of the trays. It is difficult to measure ABV in real time so we use the tray temperature as a proxy for the ABV. Because we are measuring temperatures all the time we come to think of the temperature as the variable that we are controlling, but remember it is actually the ABV that you are controlling and the temperature is just an alias for ABV.
  11. The setup that the Chinese have supplied to you is "fairly similar" to the standard design supplied by Affordable Distillery Equipment which is run be member @Southernhighlander. If anyone can solve your problem it is him. My own impression is that the flow problem is likely caused by air locks in the liquid drain piping. Air locks can occur at any high point where air gets trapped and cannot be flushed out. In particular I suspect the "S" traps which have been installed on the outlets of each of the columns. In many countries these "S" traps are forbidden in the plumbing codes for waste water for exactly this reason. It would be better to use standard "U" traps which eliminate the high points where air collects. The second likely problem point is the "horizontal" section of the drain pipe from the columns back to the pot. No drain pipe that is gravity driven should ever be horizontal because it is so easy to accidentally get a high spot. Horizontal drains should have a slope of at least 1 % ( 1 inch fall per 100 inches of run). This is often difficult to rectify after installation without major reconstruction. The last problem point I have seen is the dip pipe inside the pot. This usually dips down well under the liquid surface to prevent vapor from flowing back up the liquid drain pipe - which would also cause draining issues. However, the dip pipe will be full of air at start up and if the liquid flow down the drain is not high enough it can't flush the air out. The solution is to drill a small hole ( 3mm or 1/8 inch ) in the dip pipe (edit) inside the pot and above the normal liquid level. The small size will prevent a high enough vapor flow to cause problems but will gradually allow any trapped air to escape from the pipe.
  12. Rotavaps often come with vacuum pumps, so if you are pulling a vacuum you must make sure that your cooling water temperature is low enough to condense the alcohol that is evaporated. Generally with rotavaps it is the solids that are left behind that you want, but in this case it is the evaporated alcohol that is the important bit. Turn the vacuum pump off if you can. High solids can also cause problems when working strictly to the TTB method. See my earlier post at
  13. The fermentation yield depends on a host of different variables, but if you know that there was 12% ABV in the wash then the fact that you produced only 25 liters of distillate is not due to anything being wrong with the fermentation yield. 300 liters of wash at 12% ABV distilled to 94% ABV should give you around 38 liters of total distillate (i.e not just the hearts). There are 3 areas where you should start looking for the problem. Firstly, how did you measure the 12% in the wash? This is quite a high level of alcohol for a molasses fermentation and maybe the alcohol was never there to be recovered. The second potential problem would be losses in the distillation process. If you are doing a batch distillation then the only way to lose alcohol is if uncondensed vapors are passing through the condenser. Was your condenser running cold enough? Distillation efficiency should be 98%+. Lastly you should check if any alcohol was left in the pot after distillation.
  14. Thatch, the difference is that the TTB distillation procedure is the officially sanctioned method. But it is only legally necessary to carry out this full procedure on your final product to verify what you are selling. The distillation procedure is very slow and if you had to do this at every step in the blending process you would never get the product out the door. So it makes things much faster if you can calculate or measure (by some easier method) the ABV/Proof at intermediate stages. Also, if you do carry out the full distillation procedure and you find that your proof is slightly out you need calculation procedures to determine what should be added to correct the alcohol and sugar levels. Without the ability to adjust the alcohol and sugar levels correctly it becomes a guessing game that can take ages. These calculations are much the same as those to determine the proof so mastering them also means that you can set your recipe up more accurately from the beginning and are more likely to hit the target proof. There are instrument vendors who claim that their machines produce results that are acceptable to the TTB and you might have read my posts where I have questioned this and stated that the distillation procedure is mandatory. I am still seeking full clarity on this but at this stage it seems to me that unofficially the inspectors will accept the results from these machines if you can show that you have done sufficient checking on your products to prove that the machine gives the same result as the distillation procedure. But I can't guarantee that that is the true situation. In summary, the calculation procedures and the good instruments speed up the process but at the end of the day you must have sufficient distillation results to show that you are shipping on-spec product. Sorry for causing confusion.
  15. You can calculate the ABV, and the way you have done it is correct. The only wrinkle is your factor of 1 kg sugar = 629 ml volume increase. This is not a fixed ratio unfortunately. Sugar dissolving in alcohol and water is similar to mixing alcohol and water in that the volumes are not additive and the volume increase when you add 1 kg of sugar will vary depending on the total quantity of sugar and the proof of the spirit. Based on our previous offline discussions I guess that you somehow extracted this factor from a calculation in AlcoDens LQ. Here is the same calculation shown in the AlcoDens LQ liqueur blending calculator (the half drop of water is just a rounding error!). The way this calculator is set up it expects you to tell it what proof and brix you want in the product and then it will calculate the quantities of spirit and sugar required. You are attacking the problem from the other direction - you are specifying the quantities of the ingredients and wanting to know the final proof. If you are interested, write to me and I will send you a spreadsheet that you can use together with AlcoDens LQ to solve the problem when you already know the quantities and you want to calculate the final proof.
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